diff options
Diffstat (limited to 'tools/plink/sshdes.c')
| -rw-r--r-- | tools/plink/sshdes.c | 2119 |
1 files changed, 1088 insertions, 1031 deletions
diff --git a/tools/plink/sshdes.c b/tools/plink/sshdes.c index 0beb273ce..f54990e7c 100644 --- a/tools/plink/sshdes.c +++ b/tools/plink/sshdes.c @@ -1,1031 +1,1088 @@ -#include <assert.h>
-#include "ssh.h"
-
-
-/* des.c - implementation of DES
- */
-
-/*
- * Description of DES
- * ------------------
- *
- * Unlike the description in FIPS 46, I'm going to use _sensible_ indices:
- * bits in an n-bit word are numbered from 0 at the LSB to n-1 at the MSB.
- * And S-boxes are indexed by six consecutive bits, not by the outer two
- * followed by the middle four.
- *
- * The DES encryption routine requires a 64-bit input, and a key schedule K
- * containing 16 48-bit elements.
- *
- * First the input is permuted by the initial permutation IP.
- * Then the input is split into 32-bit words L and R. (L is the MSW.)
- * Next, 16 rounds. In each round:
- * (L, R) <- (R, L xor f(R, K[i]))
- * Then the pre-output words L and R are swapped.
- * Then L and R are glued back together into a 64-bit word. (L is the MSW,
- * again, but since we just swapped them, the MSW is the R that came out
- * of the last round.)
- * The 64-bit output block is permuted by the inverse of IP and returned.
- *
- * Decryption is identical except that the elements of K are used in the
- * opposite order. (This wouldn't work if that word swap didn't happen.)
- *
- * The function f, used in each round, accepts a 32-bit word R and a
- * 48-bit key block K. It produces a 32-bit output.
- *
- * First R is expanded to 48 bits using the bit-selection function E.
- * The resulting 48-bit block is XORed with the key block K to produce
- * a 48-bit block X.
- * This block X is split into eight groups of 6 bits. Each group of 6
- * bits is then looked up in one of the eight S-boxes to convert
- * it to 4 bits. These eight groups of 4 bits are glued back
- * together to produce a 32-bit preoutput block.
- * The preoutput block is permuted using the permutation P and returned.
- *
- * Key setup maps a 64-bit key word into a 16x48-bit key schedule. Although
- * the approved input format for the key is a 64-bit word, eight of the
- * bits are discarded, so the actual quantity of key used is 56 bits.
- *
- * First the input key is converted to two 28-bit words C and D using
- * the bit-selection function PC1.
- * Then 16 rounds of key setup occur. In each round, C and D are each
- * rotated left by either 1 or 2 bits (depending on which round), and
- * then converted into a key schedule element using the bit-selection
- * function PC2.
- *
- * That's the actual algorithm. Now for the tedious details: all those
- * painful permutations and lookup tables.
- *
- * IP is a 64-to-64 bit permutation. Its output contains the following
- * bits of its input (listed in order MSB to LSB of output).
- *
- * 6 14 22 30 38 46 54 62 4 12 20 28 36 44 52 60
- * 2 10 18 26 34 42 50 58 0 8 16 24 32 40 48 56
- * 7 15 23 31 39 47 55 63 5 13 21 29 37 45 53 61
- * 3 11 19 27 35 43 51 59 1 9 17 25 33 41 49 57
- *
- * E is a 32-to-48 bit selection function. Its output contains the following
- * bits of its input (listed in order MSB to LSB of output).
- *
- * 0 31 30 29 28 27 28 27 26 25 24 23 24 23 22 21 20 19 20 19 18 17 16 15
- * 16 15 14 13 12 11 12 11 10 9 8 7 8 7 6 5 4 3 4 3 2 1 0 31
- *
- * The S-boxes are arbitrary table-lookups each mapping a 6-bit input to a
- * 4-bit output. In other words, each S-box is an array[64] of 4-bit numbers.
- * The S-boxes are listed below. The first S-box listed is applied to the
- * most significant six bits of the block X; the last one is applied to the
- * least significant.
- *
- * 14 0 4 15 13 7 1 4 2 14 15 2 11 13 8 1
- * 3 10 10 6 6 12 12 11 5 9 9 5 0 3 7 8
- * 4 15 1 12 14 8 8 2 13 4 6 9 2 1 11 7
- * 15 5 12 11 9 3 7 14 3 10 10 0 5 6 0 13
- *
- * 15 3 1 13 8 4 14 7 6 15 11 2 3 8 4 14
- * 9 12 7 0 2 1 13 10 12 6 0 9 5 11 10 5
- * 0 13 14 8 7 10 11 1 10 3 4 15 13 4 1 2
- * 5 11 8 6 12 7 6 12 9 0 3 5 2 14 15 9
- *
- * 10 13 0 7 9 0 14 9 6 3 3 4 15 6 5 10
- * 1 2 13 8 12 5 7 14 11 12 4 11 2 15 8 1
- * 13 1 6 10 4 13 9 0 8 6 15 9 3 8 0 7
- * 11 4 1 15 2 14 12 3 5 11 10 5 14 2 7 12
- *
- * 7 13 13 8 14 11 3 5 0 6 6 15 9 0 10 3
- * 1 4 2 7 8 2 5 12 11 1 12 10 4 14 15 9
- * 10 3 6 15 9 0 0 6 12 10 11 1 7 13 13 8
- * 15 9 1 4 3 5 14 11 5 12 2 7 8 2 4 14
- *
- * 2 14 12 11 4 2 1 12 7 4 10 7 11 13 6 1
- * 8 5 5 0 3 15 15 10 13 3 0 9 14 8 9 6
- * 4 11 2 8 1 12 11 7 10 1 13 14 7 2 8 13
- * 15 6 9 15 12 0 5 9 6 10 3 4 0 5 14 3
- *
- * 12 10 1 15 10 4 15 2 9 7 2 12 6 9 8 5
- * 0 6 13 1 3 13 4 14 14 0 7 11 5 3 11 8
- * 9 4 14 3 15 2 5 12 2 9 8 5 12 15 3 10
- * 7 11 0 14 4 1 10 7 1 6 13 0 11 8 6 13
- *
- * 4 13 11 0 2 11 14 7 15 4 0 9 8 1 13 10
- * 3 14 12 3 9 5 7 12 5 2 10 15 6 8 1 6
- * 1 6 4 11 11 13 13 8 12 1 3 4 7 10 14 7
- * 10 9 15 5 6 0 8 15 0 14 5 2 9 3 2 12
- *
- * 13 1 2 15 8 13 4 8 6 10 15 3 11 7 1 4
- * 10 12 9 5 3 6 14 11 5 0 0 14 12 9 7 2
- * 7 2 11 1 4 14 1 7 9 4 12 10 14 8 2 13
- * 0 15 6 12 10 9 13 0 15 3 3 5 5 6 8 11
- *
- * P is a 32-to-32 bit permutation. Its output contains the following
- * bits of its input (listed in order MSB to LSB of output).
- *
- * 16 25 12 11 3 20 4 15 31 17 9 6 27 14 1 22
- * 30 24 8 18 0 5 29 23 13 19 2 26 10 21 28 7
- *
- * PC1 is a 64-to-56 bit selection function. Its output is in two words,
- * C and D. The word C contains the following bits of its input (listed
- * in order MSB to LSB of output).
- *
- * 7 15 23 31 39 47 55 63 6 14 22 30 38 46
- * 54 62 5 13 21 29 37 45 53 61 4 12 20 28
- *
- * And the word D contains these bits.
- *
- * 1 9 17 25 33 41 49 57 2 10 18 26 34 42
- * 50 58 3 11 19 27 35 43 51 59 36 44 52 60
- *
- * PC2 is a 56-to-48 bit selection function. Its input is in two words,
- * C and D. These are treated as one 56-bit word (with C more significant,
- * so that bits 55 to 28 of the word are bits 27 to 0 of C, and bits 27 to
- * 0 of the word are bits 27 to 0 of D). The output contains the following
- * bits of this 56-bit input word (listed in order MSB to LSB of output).
- *
- * 42 39 45 32 55 51 53 28 41 50 35 46 33 37 44 52 30 48 40 49 29 36 43 54
- * 15 4 25 19 9 1 26 16 5 11 23 8 12 7 17 0 22 3 10 14 6 20 27 24
- */
-
-/*
- * Implementation details
- * ----------------------
- *
- * If you look at the code in this module, you'll find it looks
- * nothing _like_ the above algorithm. Here I explain the
- * differences...
- *
- * Key setup has not been heavily optimised here. We are not
- * concerned with key agility: we aren't codebreakers. We don't
- * mind a little delay (and it really is a little one; it may be a
- * factor of five or so slower than it could be but it's still not
- * an appreciable length of time) while setting up. The only tweaks
- * in the key setup are ones which change the format of the key
- * schedule to speed up the actual encryption. I'll describe those
- * below.
- *
- * The first and most obvious optimisation is the S-boxes. Since
- * each S-box always targets the same four bits in the final 32-bit
- * word, so the output from (for example) S-box 0 must always be
- * shifted left 28 bits, we can store the already-shifted outputs
- * in the lookup tables. This reduces lookup-and-shift to lookup,
- * so the S-box step is now just a question of ORing together eight
- * table lookups.
- *
- * The permutation P is just a bit order change; it's invariant
- * with respect to OR, in that P(x)|P(y) = P(x|y). Therefore, we
- * can apply P to every entry of the S-box tables and then we don't
- * have to do it in the code of f(). This yields a set of tables
- * which might be called SP-boxes.
- *
- * The bit-selection function E is our next target. Note that E is
- * immediately followed by the operation of splitting into 6-bit
- * chunks. Examining the 6-bit chunks coming out of E we notice
- * they're all contiguous within the word (speaking cyclically -
- * the end two wrap round); so we can extract those bit strings
- * individually rather than explicitly running E. This would yield
- * code such as
- *
- * y |= SPboxes[0][ (rotl(R, 5) ^ top6bitsofK) & 0x3F ];
- * t |= SPboxes[1][ (rotl(R,11) ^ next6bitsofK) & 0x3F ];
- *
- * and so on; and the key schedule preparation would have to
- * provide each 6-bit chunk separately.
- *
- * Really we'd like to XOR in the key schedule element before
- * looking up bit strings in R. This we can't do, naively, because
- * the 6-bit strings we want overlap. But look at the strings:
- *
- * 3322222222221111111111
- * bit 10987654321098765432109876543210
- *
- * box0 XXXXX X
- * box1 XXXXXX
- * box2 XXXXXX
- * box3 XXXXXX
- * box4 XXXXXX
- * box5 XXXXXX
- * box6 XXXXXX
- * box7 X XXXXX
- *
- * The bit strings we need to XOR in for boxes 0, 2, 4 and 6 don't
- * overlap with each other. Neither do the ones for boxes 1, 3, 5
- * and 7. So we could provide the key schedule in the form of two
- * words that we can separately XOR into R, and then every S-box
- * index is available as a (cyclically) contiguous 6-bit substring
- * of one or the other of the results.
- *
- * The comments in Eric Young's libdes implementation point out
- * that two of these bit strings require a rotation (rather than a
- * simple shift) to extract. It's unavoidable that at least _one_
- * must do; but we can actually run the whole inner algorithm (all
- * 16 rounds) rotated one bit to the left, so that what the `real'
- * DES description sees as L=0x80000001 we see as L=0x00000003.
- * This requires rotating all our SP-box entries one bit to the
- * left, and rotating each word of the key schedule elements one to
- * the left, and rotating L and R one bit left just after IP and
- * one bit right again just before FP. And in each round we convert
- * a rotate into a shift, so we've saved a few per cent.
- *
- * That's about it for the inner loop; the SP-box tables as listed
- * below are what I've described here (the original S value,
- * shifted to its final place in the input to P, run through P, and
- * then rotated one bit left). All that remains is to optimise the
- * initial permutation IP.
- *
- * IP is not an arbitrary permutation. It has the nice property
- * that if you take any bit number, write it in binary (6 bits),
- * permute those 6 bits and invert some of them, you get the final
- * position of that bit. Specifically, the bit whose initial
- * position is given (in binary) as fedcba ends up in position
- * AcbFED (where a capital letter denotes the inverse of a bit).
- *
- * We have the 64-bit data in two 32-bit words L and R, where bits
- * in L are those with f=1 and bits in R are those with f=0. We
- * note that we can do a simple transformation: suppose we exchange
- * the bits with f=1,c=0 and the bits with f=0,c=1. This will cause
- * the bit fedcba to be in position cedfba - we've `swapped' bits c
- * and f in the position of each bit!
- *
- * Better still, this transformation is easy. In the example above,
- * bits in L with c=0 are bits 0x0F0F0F0F, and those in R with c=1
- * are 0xF0F0F0F0. So we can do
- *
- * difference = ((R >> 4) ^ L) & 0x0F0F0F0F
- * R ^= (difference << 4)
- * L ^= difference
- *
- * to perform the swap. Let's denote this by bitswap(4,0x0F0F0F0F).
- * Also, we can invert the bit at the top just by exchanging L and
- * R. So in a few swaps and a few of these bit operations we can
- * do:
- *
- * Initially the position of bit fedcba is fedcba
- * Swap L with R to make it Fedcba
- * Perform bitswap( 4,0x0F0F0F0F) to make it cedFba
- * Perform bitswap(16,0x0000FFFF) to make it ecdFba
- * Swap L with R to make it EcdFba
- * Perform bitswap( 2,0x33333333) to make it bcdFEa
- * Perform bitswap( 8,0x00FF00FF) to make it dcbFEa
- * Swap L with R to make it DcbFEa
- * Perform bitswap( 1,0x55555555) to make it acbFED
- * Swap L with R to make it AcbFED
- *
- * (In the actual code the four swaps are implicit: R and L are
- * simply used the other way round in the first, second and last
- * bitswap operations.)
- *
- * The final permutation is just the inverse of IP, so it can be
- * performed by a similar set of operations.
- */
-
-typedef struct {
- word32 k0246[16], k1357[16];
- word32 iv0, iv1;
-} DESContext;
-
-#define rotl(x, c) ( (x << c) | (x >> (32-c)) )
-#define rotl28(x, c) ( ( (x << c) | (x >> (28-c)) ) & 0x0FFFFFFF)
-
-static word32 bitsel(word32 * input, const int *bitnums, int size)
-{
- word32 ret = 0;
- while (size--) {
- int bitpos = *bitnums++;
- ret <<= 1;
- if (bitpos >= 0)
- ret |= 1 & (input[bitpos / 32] >> (bitpos % 32));
- }
- return ret;
-}
-
-static void des_key_setup(word32 key_msw, word32 key_lsw, DESContext * sched)
-{
-
- static const int PC1_Cbits[] = {
- 7, 15, 23, 31, 39, 47, 55, 63, 6, 14, 22, 30, 38, 46,
- 54, 62, 5, 13, 21, 29, 37, 45, 53, 61, 4, 12, 20, 28
- };
- static const int PC1_Dbits[] = {
- 1, 9, 17, 25, 33, 41, 49, 57, 2, 10, 18, 26, 34, 42,
- 50, 58, 3, 11, 19, 27, 35, 43, 51, 59, 36, 44, 52, 60
- };
- /*
- * The bit numbers in the two lists below don't correspond to
- * the ones in the above description of PC2, because in the
- * above description C and D are concatenated so `bit 28' means
- * bit 0 of C. In this implementation we're using the standard
- * `bitsel' function above and C is in the second word, so bit
- * 0 of C is addressed by writing `32' here.
- */
- static const int PC2_0246[] = {
- 49, 36, 59, 55, -1, -1, 37, 41, 48, 56, 34, 52, -1, -1, 15, 4,
- 25, 19, 9, 1, -1, -1, 12, 7, 17, 0, 22, 3, -1, -1, 46, 43
- };
- static const int PC2_1357[] = {
- -1, -1, 57, 32, 45, 54, 39, 50, -1, -1, 44, 53, 33, 40, 47, 58,
- -1, -1, 26, 16, 5, 11, 23, 8, -1, -1, 10, 14, 6, 20, 27, 24
- };
- static const int leftshifts[] =
- { 1, 1, 2, 2, 2, 2, 2, 2, 1, 2, 2, 2, 2, 2, 2, 1 };
-
- word32 C, D;
- word32 buf[2];
- int i;
-
- buf[0] = key_lsw;
- buf[1] = key_msw;
-
- C = bitsel(buf, PC1_Cbits, 28);
- D = bitsel(buf, PC1_Dbits, 28);
-
- for (i = 0; i < 16; i++) {
- C = rotl28(C, leftshifts[i]);
- D = rotl28(D, leftshifts[i]);
- buf[0] = D;
- buf[1] = C;
- sched->k0246[i] = bitsel(buf, PC2_0246, 32);
- sched->k1357[i] = bitsel(buf, PC2_1357, 32);
- }
-
- sched->iv0 = sched->iv1 = 0;
-}
-
-static const word32 SPboxes[8][64] = {
- {0x01010400, 0x00000000, 0x00010000, 0x01010404,
- 0x01010004, 0x00010404, 0x00000004, 0x00010000,
- 0x00000400, 0x01010400, 0x01010404, 0x00000400,
- 0x01000404, 0x01010004, 0x01000000, 0x00000004,
- 0x00000404, 0x01000400, 0x01000400, 0x00010400,
- 0x00010400, 0x01010000, 0x01010000, 0x01000404,
- 0x00010004, 0x01000004, 0x01000004, 0x00010004,
- 0x00000000, 0x00000404, 0x00010404, 0x01000000,
- 0x00010000, 0x01010404, 0x00000004, 0x01010000,
- 0x01010400, 0x01000000, 0x01000000, 0x00000400,
- 0x01010004, 0x00010000, 0x00010400, 0x01000004,
- 0x00000400, 0x00000004, 0x01000404, 0x00010404,
- 0x01010404, 0x00010004, 0x01010000, 0x01000404,
- 0x01000004, 0x00000404, 0x00010404, 0x01010400,
- 0x00000404, 0x01000400, 0x01000400, 0x00000000,
- 0x00010004, 0x00010400, 0x00000000, 0x01010004L},
-
- {0x80108020, 0x80008000, 0x00008000, 0x00108020,
- 0x00100000, 0x00000020, 0x80100020, 0x80008020,
- 0x80000020, 0x80108020, 0x80108000, 0x80000000,
- 0x80008000, 0x00100000, 0x00000020, 0x80100020,
- 0x00108000, 0x00100020, 0x80008020, 0x00000000,
- 0x80000000, 0x00008000, 0x00108020, 0x80100000,
- 0x00100020, 0x80000020, 0x00000000, 0x00108000,
- 0x00008020, 0x80108000, 0x80100000, 0x00008020,
- 0x00000000, 0x00108020, 0x80100020, 0x00100000,
- 0x80008020, 0x80100000, 0x80108000, 0x00008000,
- 0x80100000, 0x80008000, 0x00000020, 0x80108020,
- 0x00108020, 0x00000020, 0x00008000, 0x80000000,
- 0x00008020, 0x80108000, 0x00100000, 0x80000020,
- 0x00100020, 0x80008020, 0x80000020, 0x00100020,
- 0x00108000, 0x00000000, 0x80008000, 0x00008020,
- 0x80000000, 0x80100020, 0x80108020, 0x00108000L},
-
- {0x00000208, 0x08020200, 0x00000000, 0x08020008,
- 0x08000200, 0x00000000, 0x00020208, 0x08000200,
- 0x00020008, 0x08000008, 0x08000008, 0x00020000,
- 0x08020208, 0x00020008, 0x08020000, 0x00000208,
- 0x08000000, 0x00000008, 0x08020200, 0x00000200,
- 0x00020200, 0x08020000, 0x08020008, 0x00020208,
- 0x08000208, 0x00020200, 0x00020000, 0x08000208,
- 0x00000008, 0x08020208, 0x00000200, 0x08000000,
- 0x08020200, 0x08000000, 0x00020008, 0x00000208,
- 0x00020000, 0x08020200, 0x08000200, 0x00000000,
- 0x00000200, 0x00020008, 0x08020208, 0x08000200,
- 0x08000008, 0x00000200, 0x00000000, 0x08020008,
- 0x08000208, 0x00020000, 0x08000000, 0x08020208,
- 0x00000008, 0x00020208, 0x00020200, 0x08000008,
- 0x08020000, 0x08000208, 0x00000208, 0x08020000,
- 0x00020208, 0x00000008, 0x08020008, 0x00020200L},
-
- {0x00802001, 0x00002081, 0x00002081, 0x00000080,
- 0x00802080, 0x00800081, 0x00800001, 0x00002001,
- 0x00000000, 0x00802000, 0x00802000, 0x00802081,
- 0x00000081, 0x00000000, 0x00800080, 0x00800001,
- 0x00000001, 0x00002000, 0x00800000, 0x00802001,
- 0x00000080, 0x00800000, 0x00002001, 0x00002080,
- 0x00800081, 0x00000001, 0x00002080, 0x00800080,
- 0x00002000, 0x00802080, 0x00802081, 0x00000081,
- 0x00800080, 0x00800001, 0x00802000, 0x00802081,
- 0x00000081, 0x00000000, 0x00000000, 0x00802000,
- 0x00002080, 0x00800080, 0x00800081, 0x00000001,
- 0x00802001, 0x00002081, 0x00002081, 0x00000080,
- 0x00802081, 0x00000081, 0x00000001, 0x00002000,
- 0x00800001, 0x00002001, 0x00802080, 0x00800081,
- 0x00002001, 0x00002080, 0x00800000, 0x00802001,
- 0x00000080, 0x00800000, 0x00002000, 0x00802080L},
-
- {0x00000100, 0x02080100, 0x02080000, 0x42000100,
- 0x00080000, 0x00000100, 0x40000000, 0x02080000,
- 0x40080100, 0x00080000, 0x02000100, 0x40080100,
- 0x42000100, 0x42080000, 0x00080100, 0x40000000,
- 0x02000000, 0x40080000, 0x40080000, 0x00000000,
- 0x40000100, 0x42080100, 0x42080100, 0x02000100,
- 0x42080000, 0x40000100, 0x00000000, 0x42000000,
- 0x02080100, 0x02000000, 0x42000000, 0x00080100,
- 0x00080000, 0x42000100, 0x00000100, 0x02000000,
- 0x40000000, 0x02080000, 0x42000100, 0x40080100,
- 0x02000100, 0x40000000, 0x42080000, 0x02080100,
- 0x40080100, 0x00000100, 0x02000000, 0x42080000,
- 0x42080100, 0x00080100, 0x42000000, 0x42080100,
- 0x02080000, 0x00000000, 0x40080000, 0x42000000,
- 0x00080100, 0x02000100, 0x40000100, 0x00080000,
- 0x00000000, 0x40080000, 0x02080100, 0x40000100L},
-
- {0x20000010, 0x20400000, 0x00004000, 0x20404010,
- 0x20400000, 0x00000010, 0x20404010, 0x00400000,
- 0x20004000, 0x00404010, 0x00400000, 0x20000010,
- 0x00400010, 0x20004000, 0x20000000, 0x00004010,
- 0x00000000, 0x00400010, 0x20004010, 0x00004000,
- 0x00404000, 0x20004010, 0x00000010, 0x20400010,
- 0x20400010, 0x00000000, 0x00404010, 0x20404000,
- 0x00004010, 0x00404000, 0x20404000, 0x20000000,
- 0x20004000, 0x00000010, 0x20400010, 0x00404000,
- 0x20404010, 0x00400000, 0x00004010, 0x20000010,
- 0x00400000, 0x20004000, 0x20000000, 0x00004010,
- 0x20000010, 0x20404010, 0x00404000, 0x20400000,
- 0x00404010, 0x20404000, 0x00000000, 0x20400010,
- 0x00000010, 0x00004000, 0x20400000, 0x00404010,
- 0x00004000, 0x00400010, 0x20004010, 0x00000000,
- 0x20404000, 0x20000000, 0x00400010, 0x20004010L},
-
- {0x00200000, 0x04200002, 0x04000802, 0x00000000,
- 0x00000800, 0x04000802, 0x00200802, 0x04200800,
- 0x04200802, 0x00200000, 0x00000000, 0x04000002,
- 0x00000002, 0x04000000, 0x04200002, 0x00000802,
- 0x04000800, 0x00200802, 0x00200002, 0x04000800,
- 0x04000002, 0x04200000, 0x04200800, 0x00200002,
- 0x04200000, 0x00000800, 0x00000802, 0x04200802,
- 0x00200800, 0x00000002, 0x04000000, 0x00200800,
- 0x04000000, 0x00200800, 0x00200000, 0x04000802,
- 0x04000802, 0x04200002, 0x04200002, 0x00000002,
- 0x00200002, 0x04000000, 0x04000800, 0x00200000,
- 0x04200800, 0x00000802, 0x00200802, 0x04200800,
- 0x00000802, 0x04000002, 0x04200802, 0x04200000,
- 0x00200800, 0x00000000, 0x00000002, 0x04200802,
- 0x00000000, 0x00200802, 0x04200000, 0x00000800,
- 0x04000002, 0x04000800, 0x00000800, 0x00200002L},
-
- {0x10001040, 0x00001000, 0x00040000, 0x10041040,
- 0x10000000, 0x10001040, 0x00000040, 0x10000000,
- 0x00040040, 0x10040000, 0x10041040, 0x00041000,
- 0x10041000, 0x00041040, 0x00001000, 0x00000040,
- 0x10040000, 0x10000040, 0x10001000, 0x00001040,
- 0x00041000, 0x00040040, 0x10040040, 0x10041000,
- 0x00001040, 0x00000000, 0x00000000, 0x10040040,
- 0x10000040, 0x10001000, 0x00041040, 0x00040000,
- 0x00041040, 0x00040000, 0x10041000, 0x00001000,
- 0x00000040, 0x10040040, 0x00001000, 0x00041040,
- 0x10001000, 0x00000040, 0x10000040, 0x10040000,
- 0x10040040, 0x10000000, 0x00040000, 0x10001040,
- 0x00000000, 0x10041040, 0x00040040, 0x10000040,
- 0x10040000, 0x10001000, 0x10001040, 0x00000000,
- 0x10041040, 0x00041000, 0x00041000, 0x00001040,
- 0x00001040, 0x00040040, 0x10000000, 0x10041000L}
-};
-
-#define f(R, K0246, K1357) (\
- s0246 = R ^ K0246, \
- s1357 = R ^ K1357, \
- s0246 = rotl(s0246, 28), \
- SPboxes[0] [(s0246 >> 24) & 0x3F] | \
- SPboxes[1] [(s1357 >> 24) & 0x3F] | \
- SPboxes[2] [(s0246 >> 16) & 0x3F] | \
- SPboxes[3] [(s1357 >> 16) & 0x3F] | \
- SPboxes[4] [(s0246 >> 8) & 0x3F] | \
- SPboxes[5] [(s1357 >> 8) & 0x3F] | \
- SPboxes[6] [(s0246 ) & 0x3F] | \
- SPboxes[7] [(s1357 ) & 0x3F])
-
-#define bitswap(L, R, n, mask) (\
- swap = mask & ( (R >> n) ^ L ), \
- R ^= swap << n, \
- L ^= swap)
-
-/* Initial permutation */
-#define IP(L, R) (\
- bitswap(R, L, 4, 0x0F0F0F0F), \
- bitswap(R, L, 16, 0x0000FFFF), \
- bitswap(L, R, 2, 0x33333333), \
- bitswap(L, R, 8, 0x00FF00FF), \
- bitswap(R, L, 1, 0x55555555))
-
-/* Final permutation */
-#define FP(L, R) (\
- bitswap(R, L, 1, 0x55555555), \
- bitswap(L, R, 8, 0x00FF00FF), \
- bitswap(L, R, 2, 0x33333333), \
- bitswap(R, L, 16, 0x0000FFFF), \
- bitswap(R, L, 4, 0x0F0F0F0F))
-
-static void des_encipher(word32 * output, word32 L, word32 R,
- DESContext * sched)
-{
- word32 swap, s0246, s1357;
-
- IP(L, R);
-
- L = rotl(L, 1);
- R = rotl(R, 1);
-
- L ^= f(R, sched->k0246[0], sched->k1357[0]);
- R ^= f(L, sched->k0246[1], sched->k1357[1]);
- L ^= f(R, sched->k0246[2], sched->k1357[2]);
- R ^= f(L, sched->k0246[3], sched->k1357[3]);
- L ^= f(R, sched->k0246[4], sched->k1357[4]);
- R ^= f(L, sched->k0246[5], sched->k1357[5]);
- L ^= f(R, sched->k0246[6], sched->k1357[6]);
- R ^= f(L, sched->k0246[7], sched->k1357[7]);
- L ^= f(R, sched->k0246[8], sched->k1357[8]);
- R ^= f(L, sched->k0246[9], sched->k1357[9]);
- L ^= f(R, sched->k0246[10], sched->k1357[10]);
- R ^= f(L, sched->k0246[11], sched->k1357[11]);
- L ^= f(R, sched->k0246[12], sched->k1357[12]);
- R ^= f(L, sched->k0246[13], sched->k1357[13]);
- L ^= f(R, sched->k0246[14], sched->k1357[14]);
- R ^= f(L, sched->k0246[15], sched->k1357[15]);
-
- L = rotl(L, 31);
- R = rotl(R, 31);
-
- swap = L;
- L = R;
- R = swap;
-
- FP(L, R);
-
- output[0] = L;
- output[1] = R;
-}
-
-static void des_decipher(word32 * output, word32 L, word32 R,
- DESContext * sched)
-{
- word32 swap, s0246, s1357;
-
- IP(L, R);
-
- L = rotl(L, 1);
- R = rotl(R, 1);
-
- L ^= f(R, sched->k0246[15], sched->k1357[15]);
- R ^= f(L, sched->k0246[14], sched->k1357[14]);
- L ^= f(R, sched->k0246[13], sched->k1357[13]);
- R ^= f(L, sched->k0246[12], sched->k1357[12]);
- L ^= f(R, sched->k0246[11], sched->k1357[11]);
- R ^= f(L, sched->k0246[10], sched->k1357[10]);
- L ^= f(R, sched->k0246[9], sched->k1357[9]);
- R ^= f(L, sched->k0246[8], sched->k1357[8]);
- L ^= f(R, sched->k0246[7], sched->k1357[7]);
- R ^= f(L, sched->k0246[6], sched->k1357[6]);
- L ^= f(R, sched->k0246[5], sched->k1357[5]);
- R ^= f(L, sched->k0246[4], sched->k1357[4]);
- L ^= f(R, sched->k0246[3], sched->k1357[3]);
- R ^= f(L, sched->k0246[2], sched->k1357[2]);
- L ^= f(R, sched->k0246[1], sched->k1357[1]);
- R ^= f(L, sched->k0246[0], sched->k1357[0]);
-
- L = rotl(L, 31);
- R = rotl(R, 31);
-
- swap = L;
- L = R;
- R = swap;
-
- FP(L, R);
-
- output[0] = L;
- output[1] = R;
-}
-
-static void des_cbc_encrypt(unsigned char *blk,
- unsigned int len, DESContext * sched)
-{
- word32 out[2], iv0, iv1;
- unsigned int i;
-
- assert((len & 7) == 0);
-
- iv0 = sched->iv0;
- iv1 = sched->iv1;
- for (i = 0; i < len; i += 8) {
- iv0 ^= GET_32BIT_MSB_FIRST(blk);
- iv1 ^= GET_32BIT_MSB_FIRST(blk + 4);
- des_encipher(out, iv0, iv1, sched);
- iv0 = out[0];
- iv1 = out[1];
- PUT_32BIT_MSB_FIRST(blk, iv0);
- PUT_32BIT_MSB_FIRST(blk + 4, iv1);
- blk += 8;
- }
- sched->iv0 = iv0;
- sched->iv1 = iv1;
-}
-
-static void des_cbc_decrypt(unsigned char *blk,
- unsigned int len, DESContext * sched)
-{
- word32 out[2], iv0, iv1, xL, xR;
- unsigned int i;
-
- assert((len & 7) == 0);
-
- iv0 = sched->iv0;
- iv1 = sched->iv1;
- for (i = 0; i < len; i += 8) {
- xL = GET_32BIT_MSB_FIRST(blk);
- xR = GET_32BIT_MSB_FIRST(blk + 4);
- des_decipher(out, xL, xR, sched);
- iv0 ^= out[0];
- iv1 ^= out[1];
- PUT_32BIT_MSB_FIRST(blk, iv0);
- PUT_32BIT_MSB_FIRST(blk + 4, iv1);
- blk += 8;
- iv0 = xL;
- iv1 = xR;
- }
- sched->iv0 = iv0;
- sched->iv1 = iv1;
-}
-
-static void des_3cbc_encrypt(unsigned char *blk,
- unsigned int len, DESContext * scheds)
-{
- des_cbc_encrypt(blk, len, &scheds[0]);
- des_cbc_decrypt(blk, len, &scheds[1]);
- des_cbc_encrypt(blk, len, &scheds[2]);
-}
-
-static void des_cbc3_encrypt(unsigned char *blk,
- unsigned int len, DESContext * scheds)
-{
- word32 out[2], iv0, iv1;
- unsigned int i;
-
- assert((len & 7) == 0);
-
- iv0 = scheds->iv0;
- iv1 = scheds->iv1;
- for (i = 0; i < len; i += 8) {
- iv0 ^= GET_32BIT_MSB_FIRST(blk);
- iv1 ^= GET_32BIT_MSB_FIRST(blk + 4);
- des_encipher(out, iv0, iv1, &scheds[0]);
- des_decipher(out, out[0], out[1], &scheds[1]);
- des_encipher(out, out[0], out[1], &scheds[2]);
- iv0 = out[0];
- iv1 = out[1];
- PUT_32BIT_MSB_FIRST(blk, iv0);
- PUT_32BIT_MSB_FIRST(blk + 4, iv1);
- blk += 8;
- }
- scheds->iv0 = iv0;
- scheds->iv1 = iv1;
-}
-
-static void des_3cbc_decrypt(unsigned char *blk,
- unsigned int len, DESContext * scheds)
-{
- des_cbc_decrypt(blk, len, &scheds[2]);
- des_cbc_encrypt(blk, len, &scheds[1]);
- des_cbc_decrypt(blk, len, &scheds[0]);
-}
-
-static void des_cbc3_decrypt(unsigned char *blk,
- unsigned int len, DESContext * scheds)
-{
- word32 out[2], iv0, iv1, xL, xR;
- unsigned int i;
-
- assert((len & 7) == 0);
-
- iv0 = scheds->iv0;
- iv1 = scheds->iv1;
- for (i = 0; i < len; i += 8) {
- xL = GET_32BIT_MSB_FIRST(blk);
- xR = GET_32BIT_MSB_FIRST(blk + 4);
- des_decipher(out, xL, xR, &scheds[2]);
- des_encipher(out, out[0], out[1], &scheds[1]);
- des_decipher(out, out[0], out[1], &scheds[0]);
- iv0 ^= out[0];
- iv1 ^= out[1];
- PUT_32BIT_MSB_FIRST(blk, iv0);
- PUT_32BIT_MSB_FIRST(blk + 4, iv1);
- blk += 8;
- iv0 = xL;
- iv1 = xR;
- }
- scheds->iv0 = iv0;
- scheds->iv1 = iv1;
-}
-
-static void des_sdctr3(unsigned char *blk,
- unsigned int len, DESContext * scheds)
-{
- word32 b[2], iv0, iv1, tmp;
- unsigned int i;
-
- assert((len & 7) == 0);
-
- iv0 = scheds->iv0;
- iv1 = scheds->iv1;
- for (i = 0; i < len; i += 8) {
- des_encipher(b, iv0, iv1, &scheds[0]);
- des_decipher(b, b[0], b[1], &scheds[1]);
- des_encipher(b, b[0], b[1], &scheds[2]);
- tmp = GET_32BIT_MSB_FIRST(blk);
- PUT_32BIT_MSB_FIRST(blk, tmp ^ b[0]);
- blk += 4;
- tmp = GET_32BIT_MSB_FIRST(blk);
- PUT_32BIT_MSB_FIRST(blk, tmp ^ b[1]);
- blk += 4;
- if ((iv1 = (iv1 + 1) & 0xffffffff) == 0)
- iv0 = (iv0 + 1) & 0xffffffff;
- }
- scheds->iv0 = iv0;
- scheds->iv1 = iv1;
-}
-
-static void *des3_make_context(void)
-{
- return snewn(3, DESContext);
-}
-
-static void *des3_ssh1_make_context(void)
-{
- /* Need 3 keys for each direction, in SSH-1 */
- return snewn(6, DESContext);
-}
-
-static void *des_make_context(void)
-{
- return snew(DESContext);
-}
-
-static void *des_ssh1_make_context(void)
-{
- /* Need one key for each direction, in SSH-1 */
- return snewn(2, DESContext);
-}
-
-static void des3_free_context(void *handle) /* used for both 3DES and DES */
-{
- sfree(handle);
-}
-
-static void des3_key(void *handle, unsigned char *key)
-{
- DESContext *keys = (DESContext *) handle;
- des_key_setup(GET_32BIT_MSB_FIRST(key),
- GET_32BIT_MSB_FIRST(key + 4), &keys[0]);
- des_key_setup(GET_32BIT_MSB_FIRST(key + 8),
- GET_32BIT_MSB_FIRST(key + 12), &keys[1]);
- des_key_setup(GET_32BIT_MSB_FIRST(key + 16),
- GET_32BIT_MSB_FIRST(key + 20), &keys[2]);
-}
-
-static void des3_iv(void *handle, unsigned char *key)
-{
- DESContext *keys = (DESContext *) handle;
- keys[0].iv0 = GET_32BIT_MSB_FIRST(key);
- keys[0].iv1 = GET_32BIT_MSB_FIRST(key + 4);
-}
-
-static void des_key(void *handle, unsigned char *key)
-{
- DESContext *keys = (DESContext *) handle;
- des_key_setup(GET_32BIT_MSB_FIRST(key),
- GET_32BIT_MSB_FIRST(key + 4), &keys[0]);
-}
-
-static void des3_sesskey(void *handle, unsigned char *key)
-{
- DESContext *keys = (DESContext *) handle;
- des3_key(keys, key);
- des3_key(keys+3, key);
-}
-
-static void des3_encrypt_blk(void *handle, unsigned char *blk, int len)
-{
- DESContext *keys = (DESContext *) handle;
- des_3cbc_encrypt(blk, len, keys);
-}
-
-static void des3_decrypt_blk(void *handle, unsigned char *blk, int len)
-{
- DESContext *keys = (DESContext *) handle;
- des_3cbc_decrypt(blk, len, keys+3);
-}
-
-static void des3_ssh2_encrypt_blk(void *handle, unsigned char *blk, int len)
-{
- DESContext *keys = (DESContext *) handle;
- des_cbc3_encrypt(blk, len, keys);
-}
-
-static void des3_ssh2_decrypt_blk(void *handle, unsigned char *blk, int len)
-{
- DESContext *keys = (DESContext *) handle;
- des_cbc3_decrypt(blk, len, keys);
-}
-
-static void des3_ssh2_sdctr(void *handle, unsigned char *blk, int len)
-{
- DESContext *keys = (DESContext *) handle;
- des_sdctr3(blk, len, keys);
-}
-
-static void des_ssh2_encrypt_blk(void *handle, unsigned char *blk, int len)
-{
- DESContext *keys = (DESContext *) handle;
- des_cbc_encrypt(blk, len, keys);
-}
-
-static void des_ssh2_decrypt_blk(void *handle, unsigned char *blk, int len)
-{
- DESContext *keys = (DESContext *) handle;
- des_cbc_decrypt(blk, len, keys);
-}
-
-void des3_decrypt_pubkey(unsigned char *key, unsigned char *blk, int len)
-{
- DESContext ourkeys[3];
- des_key_setup(GET_32BIT_MSB_FIRST(key),
- GET_32BIT_MSB_FIRST(key + 4), &ourkeys[0]);
- des_key_setup(GET_32BIT_MSB_FIRST(key + 8),
- GET_32BIT_MSB_FIRST(key + 12), &ourkeys[1]);
- des_key_setup(GET_32BIT_MSB_FIRST(key),
- GET_32BIT_MSB_FIRST(key + 4), &ourkeys[2]);
- des_3cbc_decrypt(blk, len, ourkeys);
- memset(ourkeys, 0, sizeof(ourkeys));
-}
-
-void des3_encrypt_pubkey(unsigned char *key, unsigned char *blk, int len)
-{
- DESContext ourkeys[3];
- des_key_setup(GET_32BIT_MSB_FIRST(key),
- GET_32BIT_MSB_FIRST(key + 4), &ourkeys[0]);
- des_key_setup(GET_32BIT_MSB_FIRST(key + 8),
- GET_32BIT_MSB_FIRST(key + 12), &ourkeys[1]);
- des_key_setup(GET_32BIT_MSB_FIRST(key),
- GET_32BIT_MSB_FIRST(key + 4), &ourkeys[2]);
- des_3cbc_encrypt(blk, len, ourkeys);
- memset(ourkeys, 0, sizeof(ourkeys));
-}
-
-void des3_decrypt_pubkey_ossh(unsigned char *key, unsigned char *iv,
- unsigned char *blk, int len)
-{
- DESContext ourkeys[3];
- des_key_setup(GET_32BIT_MSB_FIRST(key),
- GET_32BIT_MSB_FIRST(key + 4), &ourkeys[0]);
- des_key_setup(GET_32BIT_MSB_FIRST(key + 8),
- GET_32BIT_MSB_FIRST(key + 12), &ourkeys[1]);
- des_key_setup(GET_32BIT_MSB_FIRST(key + 16),
- GET_32BIT_MSB_FIRST(key + 20), &ourkeys[2]);
- ourkeys[0].iv0 = GET_32BIT_MSB_FIRST(iv);
- ourkeys[0].iv1 = GET_32BIT_MSB_FIRST(iv+4);
- des_cbc3_decrypt(blk, len, ourkeys);
- memset(ourkeys, 0, sizeof(ourkeys));
-}
-
-void des3_encrypt_pubkey_ossh(unsigned char *key, unsigned char *iv,
- unsigned char *blk, int len)
-{
- DESContext ourkeys[3];
- des_key_setup(GET_32BIT_MSB_FIRST(key),
- GET_32BIT_MSB_FIRST(key + 4), &ourkeys[0]);
- des_key_setup(GET_32BIT_MSB_FIRST(key + 8),
- GET_32BIT_MSB_FIRST(key + 12), &ourkeys[1]);
- des_key_setup(GET_32BIT_MSB_FIRST(key + 16),
- GET_32BIT_MSB_FIRST(key + 20), &ourkeys[2]);
- ourkeys[0].iv0 = GET_32BIT_MSB_FIRST(iv);
- ourkeys[0].iv1 = GET_32BIT_MSB_FIRST(iv+4);
- des_cbc3_encrypt(blk, len, ourkeys);
- memset(ourkeys, 0, sizeof(ourkeys));
-}
-
-static void des_keysetup_xdmauth(unsigned char *keydata, DESContext *dc)
-{
- unsigned char key[8];
- int i, nbits, j;
- unsigned int bits;
-
- bits = 0;
- nbits = 0;
- j = 0;
- for (i = 0; i < 8; i++) {
- if (nbits < 7) {
- bits = (bits << 8) | keydata[j];
- nbits += 8;
- j++;
- }
- key[i] = (bits >> (nbits - 7)) << 1;
- bits &= ~(0x7F << (nbits - 7));
- nbits -= 7;
- }
-
- des_key_setup(GET_32BIT_MSB_FIRST(key), GET_32BIT_MSB_FIRST(key + 4), dc);
-}
-
-void des_encrypt_xdmauth(unsigned char *keydata, unsigned char *blk, int len)
-{
- DESContext dc;
- des_keysetup_xdmauth(keydata, &dc);
- des_cbc_encrypt(blk, 24, &dc);
-}
-
-void des_decrypt_xdmauth(unsigned char *keydata, unsigned char *blk, int len)
-{
- DESContext dc;
- des_keysetup_xdmauth(keydata, &dc);
- des_cbc_decrypt(blk, 24, &dc);
-}
-
-static const struct ssh2_cipher ssh_3des_ssh2 = {
- des3_make_context, des3_free_context, des3_iv, des3_key,
- des3_ssh2_encrypt_blk, des3_ssh2_decrypt_blk,
- "3des-cbc",
- 8, 168, SSH_CIPHER_IS_CBC, "triple-DES CBC"
-};
-
-static const struct ssh2_cipher ssh_3des_ssh2_ctr = {
- des3_make_context, des3_free_context, des3_iv, des3_key,
- des3_ssh2_sdctr, des3_ssh2_sdctr,
- "3des-ctr",
- 8, 168, 0, "triple-DES SDCTR"
-};
-
-/*
- * Single DES in SSH-2. "des-cbc" is marked as HISTORIC in
- * RFC 4250, referring to
- * FIPS-46-3. ("Single DES (i.e., DES) will be permitted
- * for legacy systems only.") , but ssh.com support it and
- * apparently aren't the only people to do so, so we sigh
- * and implement it anyway.
- */
-static const struct ssh2_cipher ssh_des_ssh2 = {
- des_make_context, des3_free_context, des3_iv, des_key,
- des_ssh2_encrypt_blk, des_ssh2_decrypt_blk,
- "des-cbc",
- 8, 56, SSH_CIPHER_IS_CBC, "single-DES CBC"
-};
-
-static const struct ssh2_cipher ssh_des_sshcom_ssh2 = {
- des_make_context, des3_free_context, des3_iv, des_key,
- des_ssh2_encrypt_blk, des_ssh2_decrypt_blk,
- "des-cbc@ssh.com",
- 8, 56, SSH_CIPHER_IS_CBC, "single-DES CBC"
-};
-
-static const struct ssh2_cipher *const des3_list[] = {
- &ssh_3des_ssh2_ctr,
- &ssh_3des_ssh2
-};
-
-const struct ssh2_ciphers ssh2_3des = {
- sizeof(des3_list) / sizeof(*des3_list),
- des3_list
-};
-
-static const struct ssh2_cipher *const des_list[] = {
- &ssh_des_ssh2,
- &ssh_des_sshcom_ssh2
-};
-
-const struct ssh2_ciphers ssh2_des = {
- sizeof(des_list) / sizeof(*des_list),
- des_list
-};
-
-const struct ssh_cipher ssh_3des = {
- des3_ssh1_make_context, des3_free_context, des3_sesskey,
- des3_encrypt_blk, des3_decrypt_blk,
- 8, "triple-DES inner-CBC"
-};
-
-static void des_sesskey(void *handle, unsigned char *key)
-{
- DESContext *keys = (DESContext *) handle;
- des_key(keys, key);
- des_key(keys+1, key);
-}
-
-static void des_encrypt_blk(void *handle, unsigned char *blk, int len)
-{
- DESContext *keys = (DESContext *) handle;
- des_cbc_encrypt(blk, len, keys);
-}
-
-static void des_decrypt_blk(void *handle, unsigned char *blk, int len)
-{
- DESContext *keys = (DESContext *) handle;
- des_cbc_decrypt(blk, len, keys+1);
-}
-
-const struct ssh_cipher ssh_des = {
- des_ssh1_make_context, des3_free_context, des_sesskey,
- des_encrypt_blk, des_decrypt_blk,
- 8, "single-DES CBC"
-};
+#include <assert.h> +#include "ssh.h" + + +/* des.c - implementation of DES + */ + +/* + * Description of DES + * ------------------ + * + * Unlike the description in FIPS 46, I'm going to use _sensible_ indices: + * bits in an n-bit word are numbered from 0 at the LSB to n-1 at the MSB. + * And S-boxes are indexed by six consecutive bits, not by the outer two + * followed by the middle four. + * + * The DES encryption routine requires a 64-bit input, and a key schedule K + * containing 16 48-bit elements. + * + * First the input is permuted by the initial permutation IP. + * Then the input is split into 32-bit words L and R. (L is the MSW.) + * Next, 16 rounds. In each round: + * (L, R) <- (R, L xor f(R, K[i])) + * Then the pre-output words L and R are swapped. + * Then L and R are glued back together into a 64-bit word. (L is the MSW, + * again, but since we just swapped them, the MSW is the R that came out + * of the last round.) + * The 64-bit output block is permuted by the inverse of IP and returned. + * + * Decryption is identical except that the elements of K are used in the + * opposite order. (This wouldn't work if that word swap didn't happen.) + * + * The function f, used in each round, accepts a 32-bit word R and a + * 48-bit key block K. It produces a 32-bit output. + * + * First R is expanded to 48 bits using the bit-selection function E. + * The resulting 48-bit block is XORed with the key block K to produce + * a 48-bit block X. + * This block X is split into eight groups of 6 bits. Each group of 6 + * bits is then looked up in one of the eight S-boxes to convert + * it to 4 bits. These eight groups of 4 bits are glued back + * together to produce a 32-bit preoutput block. + * The preoutput block is permuted using the permutation P and returned. + * + * Key setup maps a 64-bit key word into a 16x48-bit key schedule. Although + * the approved input format for the key is a 64-bit word, eight of the + * bits are discarded, so the actual quantity of key used is 56 bits. + * + * First the input key is converted to two 28-bit words C and D using + * the bit-selection function PC1. + * Then 16 rounds of key setup occur. In each round, C and D are each + * rotated left by either 1 or 2 bits (depending on which round), and + * then converted into a key schedule element using the bit-selection + * function PC2. + * + * That's the actual algorithm. Now for the tedious details: all those + * painful permutations and lookup tables. + * + * IP is a 64-to-64 bit permutation. Its output contains the following + * bits of its input (listed in order MSB to LSB of output). + * + * 6 14 22 30 38 46 54 62 4 12 20 28 36 44 52 60 + * 2 10 18 26 34 42 50 58 0 8 16 24 32 40 48 56 + * 7 15 23 31 39 47 55 63 5 13 21 29 37 45 53 61 + * 3 11 19 27 35 43 51 59 1 9 17 25 33 41 49 57 + * + * E is a 32-to-48 bit selection function. Its output contains the following + * bits of its input (listed in order MSB to LSB of output). + * + * 0 31 30 29 28 27 28 27 26 25 24 23 24 23 22 21 20 19 20 19 18 17 16 15 + * 16 15 14 13 12 11 12 11 10 9 8 7 8 7 6 5 4 3 4 3 2 1 0 31 + * + * The S-boxes are arbitrary table-lookups each mapping a 6-bit input to a + * 4-bit output. In other words, each S-box is an array[64] of 4-bit numbers. + * The S-boxes are listed below. The first S-box listed is applied to the + * most significant six bits of the block X; the last one is applied to the + * least significant. + * + * 14 0 4 15 13 7 1 4 2 14 15 2 11 13 8 1 + * 3 10 10 6 6 12 12 11 5 9 9 5 0 3 7 8 + * 4 15 1 12 14 8 8 2 13 4 6 9 2 1 11 7 + * 15 5 12 11 9 3 7 14 3 10 10 0 5 6 0 13 + * + * 15 3 1 13 8 4 14 7 6 15 11 2 3 8 4 14 + * 9 12 7 0 2 1 13 10 12 6 0 9 5 11 10 5 + * 0 13 14 8 7 10 11 1 10 3 4 15 13 4 1 2 + * 5 11 8 6 12 7 6 12 9 0 3 5 2 14 15 9 + * + * 10 13 0 7 9 0 14 9 6 3 3 4 15 6 5 10 + * 1 2 13 8 12 5 7 14 11 12 4 11 2 15 8 1 + * 13 1 6 10 4 13 9 0 8 6 15 9 3 8 0 7 + * 11 4 1 15 2 14 12 3 5 11 10 5 14 2 7 12 + * + * 7 13 13 8 14 11 3 5 0 6 6 15 9 0 10 3 + * 1 4 2 7 8 2 5 12 11 1 12 10 4 14 15 9 + * 10 3 6 15 9 0 0 6 12 10 11 1 7 13 13 8 + * 15 9 1 4 3 5 14 11 5 12 2 7 8 2 4 14 + * + * 2 14 12 11 4 2 1 12 7 4 10 7 11 13 6 1 + * 8 5 5 0 3 15 15 10 13 3 0 9 14 8 9 6 + * 4 11 2 8 1 12 11 7 10 1 13 14 7 2 8 13 + * 15 6 9 15 12 0 5 9 6 10 3 4 0 5 14 3 + * + * 12 10 1 15 10 4 15 2 9 7 2 12 6 9 8 5 + * 0 6 13 1 3 13 4 14 14 0 7 11 5 3 11 8 + * 9 4 14 3 15 2 5 12 2 9 8 5 12 15 3 10 + * 7 11 0 14 4 1 10 7 1 6 13 0 11 8 6 13 + * + * 4 13 11 0 2 11 14 7 15 4 0 9 8 1 13 10 + * 3 14 12 3 9 5 7 12 5 2 10 15 6 8 1 6 + * 1 6 4 11 11 13 13 8 12 1 3 4 7 10 14 7 + * 10 9 15 5 6 0 8 15 0 14 5 2 9 3 2 12 + * + * 13 1 2 15 8 13 4 8 6 10 15 3 11 7 1 4 + * 10 12 9 5 3 6 14 11 5 0 0 14 12 9 7 2 + * 7 2 11 1 4 14 1 7 9 4 12 10 14 8 2 13 + * 0 15 6 12 10 9 13 0 15 3 3 5 5 6 8 11 + * + * P is a 32-to-32 bit permutation. Its output contains the following + * bits of its input (listed in order MSB to LSB of output). + * + * 16 25 12 11 3 20 4 15 31 17 9 6 27 14 1 22 + * 30 24 8 18 0 5 29 23 13 19 2 26 10 21 28 7 + * + * PC1 is a 64-to-56 bit selection function. Its output is in two words, + * C and D. The word C contains the following bits of its input (listed + * in order MSB to LSB of output). + * + * 7 15 23 31 39 47 55 63 6 14 22 30 38 46 + * 54 62 5 13 21 29 37 45 53 61 4 12 20 28 + * + * And the word D contains these bits. + * + * 1 9 17 25 33 41 49 57 2 10 18 26 34 42 + * 50 58 3 11 19 27 35 43 51 59 36 44 52 60 + * + * PC2 is a 56-to-48 bit selection function. Its input is in two words, + * C and D. These are treated as one 56-bit word (with C more significant, + * so that bits 55 to 28 of the word are bits 27 to 0 of C, and bits 27 to + * 0 of the word are bits 27 to 0 of D). The output contains the following + * bits of this 56-bit input word (listed in order MSB to LSB of output). + * + * 42 39 45 32 55 51 53 28 41 50 35 46 33 37 44 52 30 48 40 49 29 36 43 54 + * 15 4 25 19 9 1 26 16 5 11 23 8 12 7 17 0 22 3 10 14 6 20 27 24 + */ + +/* + * Implementation details + * ---------------------- + * + * If you look at the code in this module, you'll find it looks + * nothing _like_ the above algorithm. Here I explain the + * differences... + * + * Key setup has not been heavily optimised here. We are not + * concerned with key agility: we aren't codebreakers. We don't + * mind a little delay (and it really is a little one; it may be a + * factor of five or so slower than it could be but it's still not + * an appreciable length of time) while setting up. The only tweaks + * in the key setup are ones which change the format of the key + * schedule to speed up the actual encryption. I'll describe those + * below. + * + * The first and most obvious optimisation is the S-boxes. Since + * each S-box always targets the same four bits in the final 32-bit + * word, so the output from (for example) S-box 0 must always be + * shifted left 28 bits, we can store the already-shifted outputs + * in the lookup tables. This reduces lookup-and-shift to lookup, + * so the S-box step is now just a question of ORing together eight + * table lookups. + * + * The permutation P is just a bit order change; it's invariant + * with respect to OR, in that P(x)|P(y) = P(x|y). Therefore, we + * can apply P to every entry of the S-box tables and then we don't + * have to do it in the code of f(). This yields a set of tables + * which might be called SP-boxes. + * + * The bit-selection function E is our next target. Note that E is + * immediately followed by the operation of splitting into 6-bit + * chunks. Examining the 6-bit chunks coming out of E we notice + * they're all contiguous within the word (speaking cyclically - + * the end two wrap round); so we can extract those bit strings + * individually rather than explicitly running E. This would yield + * code such as + * + * y |= SPboxes[0][ (rotl(R, 5) ^ top6bitsofK) & 0x3F ]; + * t |= SPboxes[1][ (rotl(R,11) ^ next6bitsofK) & 0x3F ]; + * + * and so on; and the key schedule preparation would have to + * provide each 6-bit chunk separately. + * + * Really we'd like to XOR in the key schedule element before + * looking up bit strings in R. This we can't do, naively, because + * the 6-bit strings we want overlap. But look at the strings: + * + * 3322222222221111111111 + * bit 10987654321098765432109876543210 + * + * box0 XXXXX X + * box1 XXXXXX + * box2 XXXXXX + * box3 XXXXXX + * box4 XXXXXX + * box5 XXXXXX + * box6 XXXXXX + * box7 X XXXXX + * + * The bit strings we need to XOR in for boxes 0, 2, 4 and 6 don't + * overlap with each other. Neither do the ones for boxes 1, 3, 5 + * and 7. So we could provide the key schedule in the form of two + * words that we can separately XOR into R, and then every S-box + * index is available as a (cyclically) contiguous 6-bit substring + * of one or the other of the results. + * + * The comments in Eric Young's libdes implementation point out + * that two of these bit strings require a rotation (rather than a + * simple shift) to extract. It's unavoidable that at least _one_ + * must do; but we can actually run the whole inner algorithm (all + * 16 rounds) rotated one bit to the left, so that what the `real' + * DES description sees as L=0x80000001 we see as L=0x00000003. + * This requires rotating all our SP-box entries one bit to the + * left, and rotating each word of the key schedule elements one to + * the left, and rotating L and R one bit left just after IP and + * one bit right again just before FP. And in each round we convert + * a rotate into a shift, so we've saved a few per cent. + * + * That's about it for the inner loop; the SP-box tables as listed + * below are what I've described here (the original S value, + * shifted to its final place in the input to P, run through P, and + * then rotated one bit left). All that remains is to optimise the + * initial permutation IP. + * + * IP is not an arbitrary permutation. It has the nice property + * that if you take any bit number, write it in binary (6 bits), + * permute those 6 bits and invert some of them, you get the final + * position of that bit. Specifically, the bit whose initial + * position is given (in binary) as fedcba ends up in position + * AcbFED (where a capital letter denotes the inverse of a bit). + * + * We have the 64-bit data in two 32-bit words L and R, where bits + * in L are those with f=1 and bits in R are those with f=0. We + * note that we can do a simple transformation: suppose we exchange + * the bits with f=1,c=0 and the bits with f=0,c=1. This will cause + * the bit fedcba to be in position cedfba - we've `swapped' bits c + * and f in the position of each bit! + * + * Better still, this transformation is easy. In the example above, + * bits in L with c=0 are bits 0x0F0F0F0F, and those in R with c=1 + * are 0xF0F0F0F0. So we can do + * + * difference = ((R >> 4) ^ L) & 0x0F0F0F0F + * R ^= (difference << 4) + * L ^= difference + * + * to perform the swap. Let's denote this by bitswap(4,0x0F0F0F0F). + * Also, we can invert the bit at the top just by exchanging L and + * R. So in a few swaps and a few of these bit operations we can + * do: + * + * Initially the position of bit fedcba is fedcba + * Swap L with R to make it Fedcba + * Perform bitswap( 4,0x0F0F0F0F) to make it cedFba + * Perform bitswap(16,0x0000FFFF) to make it ecdFba + * Swap L with R to make it EcdFba + * Perform bitswap( 2,0x33333333) to make it bcdFEa + * Perform bitswap( 8,0x00FF00FF) to make it dcbFEa + * Swap L with R to make it DcbFEa + * Perform bitswap( 1,0x55555555) to make it acbFED + * Swap L with R to make it AcbFED + * + * (In the actual code the four swaps are implicit: R and L are + * simply used the other way round in the first, second and last + * bitswap operations.) + * + * The final permutation is just the inverse of IP, so it can be + * performed by a similar set of operations. + */ + +typedef struct { + word32 k0246[16], k1357[16]; + word32 iv0, iv1; +} DESContext; + +#define rotl(x, c) ( (x << c) | (x >> (32-c)) ) +#define rotl28(x, c) ( ( (x << c) | (x >> (28-c)) ) & 0x0FFFFFFF) + +static word32 bitsel(word32 * input, const int *bitnums, int size) +{ + word32 ret = 0; + while (size--) { + int bitpos = *bitnums++; + ret <<= 1; + if (bitpos >= 0) + ret |= 1 & (input[bitpos / 32] >> (bitpos % 32)); + } + return ret; +} + +static void des_key_setup(word32 key_msw, word32 key_lsw, DESContext * sched) +{ + + static const int PC1_Cbits[] = { + 7, 15, 23, 31, 39, 47, 55, 63, 6, 14, 22, 30, 38, 46, + 54, 62, 5, 13, 21, 29, 37, 45, 53, 61, 4, 12, 20, 28 + }; + static const int PC1_Dbits[] = { + 1, 9, 17, 25, 33, 41, 49, 57, 2, 10, 18, 26, 34, 42, + 50, 58, 3, 11, 19, 27, 35, 43, 51, 59, 36, 44, 52, 60 + }; + /* + * The bit numbers in the two lists below don't correspond to + * the ones in the above description of PC2, because in the + * above description C and D are concatenated so `bit 28' means + * bit 0 of C. In this implementation we're using the standard + * `bitsel' function above and C is in the second word, so bit + * 0 of C is addressed by writing `32' here. + */ + static const int PC2_0246[] = { + 49, 36, 59, 55, -1, -1, 37, 41, 48, 56, 34, 52, -1, -1, 15, 4, + 25, 19, 9, 1, -1, -1, 12, 7, 17, 0, 22, 3, -1, -1, 46, 43 + }; + static const int PC2_1357[] = { + -1, -1, 57, 32, 45, 54, 39, 50, -1, -1, 44, 53, 33, 40, 47, 58, + -1, -1, 26, 16, 5, 11, 23, 8, -1, -1, 10, 14, 6, 20, 27, 24 + }; + static const int leftshifts[] = + { 1, 1, 2, 2, 2, 2, 2, 2, 1, 2, 2, 2, 2, 2, 2, 1 }; + + word32 C, D; + word32 buf[2]; + int i; + + buf[0] = key_lsw; + buf[1] = key_msw; + + C = bitsel(buf, PC1_Cbits, 28); + D = bitsel(buf, PC1_Dbits, 28); + + for (i = 0; i < 16; i++) { + C = rotl28(C, leftshifts[i]); + D = rotl28(D, leftshifts[i]); + buf[0] = D; + buf[1] = C; + sched->k0246[i] = bitsel(buf, PC2_0246, 32); + sched->k1357[i] = bitsel(buf, PC2_1357, 32); + } + + sched->iv0 = sched->iv1 = 0; +} + +static const word32 SPboxes[8][64] = { + {0x01010400, 0x00000000, 0x00010000, 0x01010404, + 0x01010004, 0x00010404, 0x00000004, 0x00010000, + 0x00000400, 0x01010400, 0x01010404, 0x00000400, + 0x01000404, 0x01010004, 0x01000000, 0x00000004, + 0x00000404, 0x01000400, 0x01000400, 0x00010400, + 0x00010400, 0x01010000, 0x01010000, 0x01000404, + 0x00010004, 0x01000004, 0x01000004, 0x00010004, + 0x00000000, 0x00000404, 0x00010404, 0x01000000, + 0x00010000, 0x01010404, 0x00000004, 0x01010000, + 0x01010400, 0x01000000, 0x01000000, 0x00000400, + 0x01010004, 0x00010000, 0x00010400, 0x01000004, + 0x00000400, 0x00000004, 0x01000404, 0x00010404, + 0x01010404, 0x00010004, 0x01010000, 0x01000404, + 0x01000004, 0x00000404, 0x00010404, 0x01010400, + 0x00000404, 0x01000400, 0x01000400, 0x00000000, + 0x00010004, 0x00010400, 0x00000000, 0x01010004L}, + + {0x80108020, 0x80008000, 0x00008000, 0x00108020, + 0x00100000, 0x00000020, 0x80100020, 0x80008020, + 0x80000020, 0x80108020, 0x80108000, 0x80000000, + 0x80008000, 0x00100000, 0x00000020, 0x80100020, + 0x00108000, 0x00100020, 0x80008020, 0x00000000, + 0x80000000, 0x00008000, 0x00108020, 0x80100000, + 0x00100020, 0x80000020, 0x00000000, 0x00108000, + 0x00008020, 0x80108000, 0x80100000, 0x00008020, + 0x00000000, 0x00108020, 0x80100020, 0x00100000, + 0x80008020, 0x80100000, 0x80108000, 0x00008000, + 0x80100000, 0x80008000, 0x00000020, 0x80108020, + 0x00108020, 0x00000020, 0x00008000, 0x80000000, + 0x00008020, 0x80108000, 0x00100000, 0x80000020, + 0x00100020, 0x80008020, 0x80000020, 0x00100020, + 0x00108000, 0x00000000, 0x80008000, 0x00008020, + 0x80000000, 0x80100020, 0x80108020, 0x00108000L}, + + {0x00000208, 0x08020200, 0x00000000, 0x08020008, + 0x08000200, 0x00000000, 0x00020208, 0x08000200, + 0x00020008, 0x08000008, 0x08000008, 0x00020000, + 0x08020208, 0x00020008, 0x08020000, 0x00000208, + 0x08000000, 0x00000008, 0x08020200, 0x00000200, + 0x00020200, 0x08020000, 0x08020008, 0x00020208, + 0x08000208, 0x00020200, 0x00020000, 0x08000208, + 0x00000008, 0x08020208, 0x00000200, 0x08000000, + 0x08020200, 0x08000000, 0x00020008, 0x00000208, + 0x00020000, 0x08020200, 0x08000200, 0x00000000, + 0x00000200, 0x00020008, 0x08020208, 0x08000200, + 0x08000008, 0x00000200, 0x00000000, 0x08020008, + 0x08000208, 0x00020000, 0x08000000, 0x08020208, + 0x00000008, 0x00020208, 0x00020200, 0x08000008, + 0x08020000, 0x08000208, 0x00000208, 0x08020000, + 0x00020208, 0x00000008, 0x08020008, 0x00020200L}, + + {0x00802001, 0x00002081, 0x00002081, 0x00000080, + 0x00802080, 0x00800081, 0x00800001, 0x00002001, + 0x00000000, 0x00802000, 0x00802000, 0x00802081, + 0x00000081, 0x00000000, 0x00800080, 0x00800001, + 0x00000001, 0x00002000, 0x00800000, 0x00802001, + 0x00000080, 0x00800000, 0x00002001, 0x00002080, + 0x00800081, 0x00000001, 0x00002080, 0x00800080, + 0x00002000, 0x00802080, 0x00802081, 0x00000081, + 0x00800080, 0x00800001, 0x00802000, 0x00802081, + 0x00000081, 0x00000000, 0x00000000, 0x00802000, + 0x00002080, 0x00800080, 0x00800081, 0x00000001, + 0x00802001, 0x00002081, 0x00002081, 0x00000080, + 0x00802081, 0x00000081, 0x00000001, 0x00002000, + 0x00800001, 0x00002001, 0x00802080, 0x00800081, + 0x00002001, 0x00002080, 0x00800000, 0x00802001, + 0x00000080, 0x00800000, 0x00002000, 0x00802080L}, + + {0x00000100, 0x02080100, 0x02080000, 0x42000100, + 0x00080000, 0x00000100, 0x40000000, 0x02080000, + 0x40080100, 0x00080000, 0x02000100, 0x40080100, + 0x42000100, 0x42080000, 0x00080100, 0x40000000, + 0x02000000, 0x40080000, 0x40080000, 0x00000000, + 0x40000100, 0x42080100, 0x42080100, 0x02000100, + 0x42080000, 0x40000100, 0x00000000, 0x42000000, + 0x02080100, 0x02000000, 0x42000000, 0x00080100, + 0x00080000, 0x42000100, 0x00000100, 0x02000000, + 0x40000000, 0x02080000, 0x42000100, 0x40080100, + 0x02000100, 0x40000000, 0x42080000, 0x02080100, + 0x40080100, 0x00000100, 0x02000000, 0x42080000, + 0x42080100, 0x00080100, 0x42000000, 0x42080100, + 0x02080000, 0x00000000, 0x40080000, 0x42000000, + 0x00080100, 0x02000100, 0x40000100, 0x00080000, + 0x00000000, 0x40080000, 0x02080100, 0x40000100L}, + + {0x20000010, 0x20400000, 0x00004000, 0x20404010, + 0x20400000, 0x00000010, 0x20404010, 0x00400000, + 0x20004000, 0x00404010, 0x00400000, 0x20000010, + 0x00400010, 0x20004000, 0x20000000, 0x00004010, + 0x00000000, 0x00400010, 0x20004010, 0x00004000, + 0x00404000, 0x20004010, 0x00000010, 0x20400010, + 0x20400010, 0x00000000, 0x00404010, 0x20404000, + 0x00004010, 0x00404000, 0x20404000, 0x20000000, + 0x20004000, 0x00000010, 0x20400010, 0x00404000, + 0x20404010, 0x00400000, 0x00004010, 0x20000010, + 0x00400000, 0x20004000, 0x20000000, 0x00004010, + 0x20000010, 0x20404010, 0x00404000, 0x20400000, + 0x00404010, 0x20404000, 0x00000000, 0x20400010, + 0x00000010, 0x00004000, 0x20400000, 0x00404010, + 0x00004000, 0x00400010, 0x20004010, 0x00000000, + 0x20404000, 0x20000000, 0x00400010, 0x20004010L}, + + {0x00200000, 0x04200002, 0x04000802, 0x00000000, + 0x00000800, 0x04000802, 0x00200802, 0x04200800, + 0x04200802, 0x00200000, 0x00000000, 0x04000002, + 0x00000002, 0x04000000, 0x04200002, 0x00000802, + 0x04000800, 0x00200802, 0x00200002, 0x04000800, + 0x04000002, 0x04200000, 0x04200800, 0x00200002, + 0x04200000, 0x00000800, 0x00000802, 0x04200802, + 0x00200800, 0x00000002, 0x04000000, 0x00200800, + 0x04000000, 0x00200800, 0x00200000, 0x04000802, + 0x04000802, 0x04200002, 0x04200002, 0x00000002, + 0x00200002, 0x04000000, 0x04000800, 0x00200000, + 0x04200800, 0x00000802, 0x00200802, 0x04200800, + 0x00000802, 0x04000002, 0x04200802, 0x04200000, + 0x00200800, 0x00000000, 0x00000002, 0x04200802, + 0x00000000, 0x00200802, 0x04200000, 0x00000800, + 0x04000002, 0x04000800, 0x00000800, 0x00200002L}, + + {0x10001040, 0x00001000, 0x00040000, 0x10041040, + 0x10000000, 0x10001040, 0x00000040, 0x10000000, + 0x00040040, 0x10040000, 0x10041040, 0x00041000, + 0x10041000, 0x00041040, 0x00001000, 0x00000040, + 0x10040000, 0x10000040, 0x10001000, 0x00001040, + 0x00041000, 0x00040040, 0x10040040, 0x10041000, + 0x00001040, 0x00000000, 0x00000000, 0x10040040, + 0x10000040, 0x10001000, 0x00041040, 0x00040000, + 0x00041040, 0x00040000, 0x10041000, 0x00001000, + 0x00000040, 0x10040040, 0x00001000, 0x00041040, + 0x10001000, 0x00000040, 0x10000040, 0x10040000, + 0x10040040, 0x10000000, 0x00040000, 0x10001040, + 0x00000000, 0x10041040, 0x00040040, 0x10000040, + 0x10040000, 0x10001000, 0x10001040, 0x00000000, + 0x10041040, 0x00041000, 0x00041000, 0x00001040, + 0x00001040, 0x00040040, 0x10000000, 0x10041000L} +}; + +#define f(R, K0246, K1357) (\ + s0246 = R ^ K0246, \ + s1357 = R ^ K1357, \ + s0246 = rotl(s0246, 28), \ + SPboxes[0] [(s0246 >> 24) & 0x3F] | \ + SPboxes[1] [(s1357 >> 24) & 0x3F] | \ + SPboxes[2] [(s0246 >> 16) & 0x3F] | \ + SPboxes[3] [(s1357 >> 16) & 0x3F] | \ + SPboxes[4] [(s0246 >> 8) & 0x3F] | \ + SPboxes[5] [(s1357 >> 8) & 0x3F] | \ + SPboxes[6] [(s0246 ) & 0x3F] | \ + SPboxes[7] [(s1357 ) & 0x3F]) + +#define bitswap(L, R, n, mask) (\ + swap = mask & ( (R >> n) ^ L ), \ + R ^= swap << n, \ + L ^= swap) + +/* Initial permutation */ +#define IP(L, R) (\ + bitswap(R, L, 4, 0x0F0F0F0F), \ + bitswap(R, L, 16, 0x0000FFFF), \ + bitswap(L, R, 2, 0x33333333), \ + bitswap(L, R, 8, 0x00FF00FF), \ + bitswap(R, L, 1, 0x55555555)) + +/* Final permutation */ +#define FP(L, R) (\ + bitswap(R, L, 1, 0x55555555), \ + bitswap(L, R, 8, 0x00FF00FF), \ + bitswap(L, R, 2, 0x33333333), \ + bitswap(R, L, 16, 0x0000FFFF), \ + bitswap(R, L, 4, 0x0F0F0F0F)) + +static void des_encipher(word32 * output, word32 L, word32 R, + DESContext * sched) +{ + word32 swap, s0246, s1357; + + IP(L, R); + + L = rotl(L, 1); + R = rotl(R, 1); + + L ^= f(R, sched->k0246[0], sched->k1357[0]); + R ^= f(L, sched->k0246[1], sched->k1357[1]); + L ^= f(R, sched->k0246[2], sched->k1357[2]); + R ^= f(L, sched->k0246[3], sched->k1357[3]); + L ^= f(R, sched->k0246[4], sched->k1357[4]); + R ^= f(L, sched->k0246[5], sched->k1357[5]); + L ^= f(R, sched->k0246[6], sched->k1357[6]); + R ^= f(L, sched->k0246[7], sched->k1357[7]); + L ^= f(R, sched->k0246[8], sched->k1357[8]); + R ^= f(L, sched->k0246[9], sched->k1357[9]); + L ^= f(R, sched->k0246[10], sched->k1357[10]); + R ^= f(L, sched->k0246[11], sched->k1357[11]); + L ^= f(R, sched->k0246[12], sched->k1357[12]); + R ^= f(L, sched->k0246[13], sched->k1357[13]); + L ^= f(R, sched->k0246[14], sched->k1357[14]); + R ^= f(L, sched->k0246[15], sched->k1357[15]); + + L = rotl(L, 31); + R = rotl(R, 31); + + swap = L; + L = R; + R = swap; + + FP(L, R); + + output[0] = L; + output[1] = R; +} + +static void des_decipher(word32 * output, word32 L, word32 R, + DESContext * sched) +{ + word32 swap, s0246, s1357; + + IP(L, R); + + L = rotl(L, 1); + R = rotl(R, 1); + + L ^= f(R, sched->k0246[15], sched->k1357[15]); + R ^= f(L, sched->k0246[14], sched->k1357[14]); + L ^= f(R, sched->k0246[13], sched->k1357[13]); + R ^= f(L, sched->k0246[12], sched->k1357[12]); + L ^= f(R, sched->k0246[11], sched->k1357[11]); + R ^= f(L, sched->k0246[10], sched->k1357[10]); + L ^= f(R, sched->k0246[9], sched->k1357[9]); + R ^= f(L, sched->k0246[8], sched->k1357[8]); + L ^= f(R, sched->k0246[7], sched->k1357[7]); + R ^= f(L, sched->k0246[6], sched->k1357[6]); + L ^= f(R, sched->k0246[5], sched->k1357[5]); + R ^= f(L, sched->k0246[4], sched->k1357[4]); + L ^= f(R, sched->k0246[3], sched->k1357[3]); + R ^= f(L, sched->k0246[2], sched->k1357[2]); + L ^= f(R, sched->k0246[1], sched->k1357[1]); + R ^= f(L, sched->k0246[0], sched->k1357[0]); + + L = rotl(L, 31); + R = rotl(R, 31); + + swap = L; + L = R; + R = swap; + + FP(L, R); + + output[0] = L; + output[1] = R; +} + +static void des_cbc_encrypt(unsigned char *blk, + unsigned int len, DESContext * sched) +{ + word32 out[2], iv0, iv1; + unsigned int i; + + assert((len & 7) == 0); + + iv0 = sched->iv0; + iv1 = sched->iv1; + for (i = 0; i < len; i += 8) { + iv0 ^= GET_32BIT_MSB_FIRST(blk); + iv1 ^= GET_32BIT_MSB_FIRST(blk + 4); + des_encipher(out, iv0, iv1, sched); + iv0 = out[0]; + iv1 = out[1]; + PUT_32BIT_MSB_FIRST(blk, iv0); + PUT_32BIT_MSB_FIRST(blk + 4, iv1); + blk += 8; + } + sched->iv0 = iv0; + sched->iv1 = iv1; +} + +static void des_cbc_decrypt(unsigned char *blk, + unsigned int len, DESContext * sched) +{ + word32 out[2], iv0, iv1, xL, xR; + unsigned int i; + + assert((len & 7) == 0); + + iv0 = sched->iv0; + iv1 = sched->iv1; + for (i = 0; i < len; i += 8) { + xL = GET_32BIT_MSB_FIRST(blk); + xR = GET_32BIT_MSB_FIRST(blk + 4); + des_decipher(out, xL, xR, sched); + iv0 ^= out[0]; + iv1 ^= out[1]; + PUT_32BIT_MSB_FIRST(blk, iv0); + PUT_32BIT_MSB_FIRST(blk + 4, iv1); + blk += 8; + iv0 = xL; + iv1 = xR; + } + sched->iv0 = iv0; + sched->iv1 = iv1; +} + +static void des_3cbc_encrypt(unsigned char *blk, + unsigned int len, DESContext * scheds) +{ + des_cbc_encrypt(blk, len, &scheds[0]); + des_cbc_decrypt(blk, len, &scheds[1]); + des_cbc_encrypt(blk, len, &scheds[2]); +} + +static void des_cbc3_encrypt(unsigned char *blk, + unsigned int len, DESContext * scheds) +{ + word32 out[2], iv0, iv1; + unsigned int i; + + assert((len & 7) == 0); + + iv0 = scheds->iv0; + iv1 = scheds->iv1; + for (i = 0; i < len; i += 8) { + iv0 ^= GET_32BIT_MSB_FIRST(blk); + iv1 ^= GET_32BIT_MSB_FIRST(blk + 4); + des_encipher(out, iv0, iv1, &scheds[0]); + des_decipher(out, out[0], out[1], &scheds[1]); + des_encipher(out, out[0], out[1], &scheds[2]); + iv0 = out[0]; + iv1 = out[1]; + PUT_32BIT_MSB_FIRST(blk, iv0); + PUT_32BIT_MSB_FIRST(blk + 4, iv1); + blk += 8; + } + scheds->iv0 = iv0; + scheds->iv1 = iv1; +} + +static void des_3cbc_decrypt(unsigned char *blk, + unsigned int len, DESContext * scheds) +{ + des_cbc_decrypt(blk, len, &scheds[2]); + des_cbc_encrypt(blk, len, &scheds[1]); + des_cbc_decrypt(blk, len, &scheds[0]); +} + +static void des_cbc3_decrypt(unsigned char *blk, + unsigned int len, DESContext * scheds) +{ + word32 out[2], iv0, iv1, xL, xR; + unsigned int i; + + assert((len & 7) == 0); + + iv0 = scheds->iv0; + iv1 = scheds->iv1; + for (i = 0; i < len; i += 8) { + xL = GET_32BIT_MSB_FIRST(blk); + xR = GET_32BIT_MSB_FIRST(blk + 4); + des_decipher(out, xL, xR, &scheds[2]); + des_encipher(out, out[0], out[1], &scheds[1]); + des_decipher(out, out[0], out[1], &scheds[0]); + iv0 ^= out[0]; + iv1 ^= out[1]; + PUT_32BIT_MSB_FIRST(blk, iv0); + PUT_32BIT_MSB_FIRST(blk + 4, iv1); + blk += 8; + iv0 = xL; + iv1 = xR; + } + scheds->iv0 = iv0; + scheds->iv1 = iv1; +} + +static void des_sdctr3(unsigned char *blk, + unsigned int len, DESContext * scheds) +{ + word32 b[2], iv0, iv1, tmp; + unsigned int i; + + assert((len & 7) == 0); + + iv0 = scheds->iv0; + iv1 = scheds->iv1; + for (i = 0; i < len; i += 8) { + des_encipher(b, iv0, iv1, &scheds[0]); + des_decipher(b, b[0], b[1], &scheds[1]); + des_encipher(b, b[0], b[1], &scheds[2]); + tmp = GET_32BIT_MSB_FIRST(blk); + PUT_32BIT_MSB_FIRST(blk, tmp ^ b[0]); + blk += 4; + tmp = GET_32BIT_MSB_FIRST(blk); + PUT_32BIT_MSB_FIRST(blk, tmp ^ b[1]); + blk += 4; + if ((iv1 = (iv1 + 1) & 0xffffffff) == 0) + iv0 = (iv0 + 1) & 0xffffffff; + } + scheds->iv0 = iv0; + scheds->iv1 = iv1; +} + +static void *des3_make_context(void) +{ + return snewn(3, DESContext); +} + +static void *des3_ssh1_make_context(void) +{ + /* Need 3 keys for each direction, in SSH-1 */ + return snewn(6, DESContext); +} + +static void *des_make_context(void) +{ + return snew(DESContext); +} + +static void *des_ssh1_make_context(void) +{ + /* Need one key for each direction, in SSH-1 */ + return snewn(2, DESContext); +} + +static void des3_free_context(void *handle) /* used for both 3DES and DES */ +{ + sfree(handle); +} + +static void des3_key(void *handle, unsigned char *key) +{ + DESContext *keys = (DESContext *) handle; + des_key_setup(GET_32BIT_MSB_FIRST(key), + GET_32BIT_MSB_FIRST(key + 4), &keys[0]); + des_key_setup(GET_32BIT_MSB_FIRST(key + 8), + GET_32BIT_MSB_FIRST(key + 12), &keys[1]); + des_key_setup(GET_32BIT_MSB_FIRST(key + 16), + GET_32BIT_MSB_FIRST(key + 20), &keys[2]); +} + +static void des3_iv(void *handle, unsigned char *key) +{ + DESContext *keys = (DESContext *) handle; + keys[0].iv0 = GET_32BIT_MSB_FIRST(key); + keys[0].iv1 = GET_32BIT_MSB_FIRST(key + 4); +} + +static void des_key(void *handle, unsigned char *key) +{ + DESContext *keys = (DESContext *) handle; + des_key_setup(GET_32BIT_MSB_FIRST(key), + GET_32BIT_MSB_FIRST(key + 4), &keys[0]); +} + +static void des3_sesskey(void *handle, unsigned char *key) +{ + DESContext *keys = (DESContext *) handle; + des3_key(keys, key); + des3_key(keys+3, key); +} + +static void des3_encrypt_blk(void *handle, unsigned char *blk, int len) +{ + DESContext *keys = (DESContext *) handle; + des_3cbc_encrypt(blk, len, keys); +} + +static void des3_decrypt_blk(void *handle, unsigned char *blk, int len) +{ + DESContext *keys = (DESContext *) handle; + des_3cbc_decrypt(blk, len, keys+3); +} + +static void des3_ssh2_encrypt_blk(void *handle, unsigned char *blk, int len) +{ + DESContext *keys = (DESContext *) handle; + des_cbc3_encrypt(blk, len, keys); +} + +static void des3_ssh2_decrypt_blk(void *handle, unsigned char *blk, int len) +{ + DESContext *keys = (DESContext *) handle; + des_cbc3_decrypt(blk, len, keys); +} + +static void des3_ssh2_sdctr(void *handle, unsigned char *blk, int len) +{ + DESContext *keys = (DESContext *) handle; + des_sdctr3(blk, len, keys); +} + +static void des_ssh2_encrypt_blk(void *handle, unsigned char *blk, int len) +{ + DESContext *keys = (DESContext *) handle; + des_cbc_encrypt(blk, len, keys); +} + +static void des_ssh2_decrypt_blk(void *handle, unsigned char *blk, int len) +{ + DESContext *keys = (DESContext *) handle; + des_cbc_decrypt(blk, len, keys); +} + +void des3_decrypt_pubkey(unsigned char *key, unsigned char *blk, int len) +{ + DESContext ourkeys[3]; + des_key_setup(GET_32BIT_MSB_FIRST(key), + GET_32BIT_MSB_FIRST(key + 4), &ourkeys[0]); + des_key_setup(GET_32BIT_MSB_FIRST(key + 8), + GET_32BIT_MSB_FIRST(key + 12), &ourkeys[1]); + des_key_setup(GET_32BIT_MSB_FIRST(key), + GET_32BIT_MSB_FIRST(key + 4), &ourkeys[2]); + des_3cbc_decrypt(blk, len, ourkeys); + smemclr(ourkeys, sizeof(ourkeys)); +} + +void des3_encrypt_pubkey(unsigned char *key, unsigned char *blk, int len) +{ + DESContext ourkeys[3]; + des_key_setup(GET_32BIT_MSB_FIRST(key), + GET_32BIT_MSB_FIRST(key + 4), &ourkeys[0]); + des_key_setup(GET_32BIT_MSB_FIRST(key + 8), + GET_32BIT_MSB_FIRST(key + 12), &ourkeys[1]); + des_key_setup(GET_32BIT_MSB_FIRST(key), + GET_32BIT_MSB_FIRST(key + 4), &ourkeys[2]); + des_3cbc_encrypt(blk, len, ourkeys); + smemclr(ourkeys, sizeof(ourkeys)); +} + +void des3_decrypt_pubkey_ossh(unsigned char *key, unsigned char *iv, + unsigned char *blk, int len) +{ + DESContext ourkeys[3]; + des_key_setup(GET_32BIT_MSB_FIRST(key), + GET_32BIT_MSB_FIRST(key + 4), &ourkeys[0]); + des_key_setup(GET_32BIT_MSB_FIRST(key + 8), + GET_32BIT_MSB_FIRST(key + 12), &ourkeys[1]); + des_key_setup(GET_32BIT_MSB_FIRST(key + 16), + GET_32BIT_MSB_FIRST(key + 20), &ourkeys[2]); + ourkeys[0].iv0 = GET_32BIT_MSB_FIRST(iv); + ourkeys[0].iv1 = GET_32BIT_MSB_FIRST(iv+4); + des_cbc3_decrypt(blk, len, ourkeys); + smemclr(ourkeys, sizeof(ourkeys)); +} + +void des3_encrypt_pubkey_ossh(unsigned char *key, unsigned char *iv, + unsigned char *blk, int len) +{ + DESContext ourkeys[3]; + des_key_setup(GET_32BIT_MSB_FIRST(key), + GET_32BIT_MSB_FIRST(key + 4), &ourkeys[0]); + des_key_setup(GET_32BIT_MSB_FIRST(key + 8), + GET_32BIT_MSB_FIRST(key + 12), &ourkeys[1]); + des_key_setup(GET_32BIT_MSB_FIRST(key + 16), + GET_32BIT_MSB_FIRST(key + 20), &ourkeys[2]); + ourkeys[0].iv0 = GET_32BIT_MSB_FIRST(iv); + ourkeys[0].iv1 = GET_32BIT_MSB_FIRST(iv+4); + des_cbc3_encrypt(blk, len, ourkeys); + smemclr(ourkeys, sizeof(ourkeys)); +} + +static void des_keysetup_xdmauth(const unsigned char *keydata, DESContext *dc) +{ + unsigned char key[8]; + int i, nbits, j; + unsigned int bits; + + bits = 0; + nbits = 0; + j = 0; + for (i = 0; i < 8; i++) { + if (nbits < 7) { + bits = (bits << 8) | keydata[j]; + nbits += 8; + j++; + } + key[i] = (bits >> (nbits - 7)) << 1; + bits &= ~(0x7F << (nbits - 7)); + nbits -= 7; + } + + des_key_setup(GET_32BIT_MSB_FIRST(key), GET_32BIT_MSB_FIRST(key + 4), dc); +} + +void des_encrypt_xdmauth(const unsigned char *keydata, + unsigned char *blk, int len) +{ + DESContext dc; + des_keysetup_xdmauth(keydata, &dc); + des_cbc_encrypt(blk, len, &dc); +} + +void des_decrypt_xdmauth(const unsigned char *keydata, + unsigned char *blk, int len) +{ + DESContext dc; + des_keysetup_xdmauth(keydata, &dc); + des_cbc_decrypt(blk, len, &dc); +} + +static const struct ssh2_cipher ssh_3des_ssh2 = { + des3_make_context, des3_free_context, des3_iv, des3_key, + des3_ssh2_encrypt_blk, des3_ssh2_decrypt_blk, + "3des-cbc", + 8, 168, SSH_CIPHER_IS_CBC, "triple-DES CBC" +}; + +static const struct ssh2_cipher ssh_3des_ssh2_ctr = { + des3_make_context, des3_free_context, des3_iv, des3_key, + des3_ssh2_sdctr, des3_ssh2_sdctr, + "3des-ctr", + 8, 168, 0, "triple-DES SDCTR" +}; + +/* + * Single DES in SSH-2. "des-cbc" is marked as HISTORIC in + * RFC 4250, referring to + * FIPS-46-3. ("Single DES (i.e., DES) will be permitted + * for legacy systems only.") , but ssh.com support it and + * apparently aren't the only people to do so, so we sigh + * and implement it anyway. + */ +static const struct ssh2_cipher ssh_des_ssh2 = { + des_make_context, des3_free_context, des3_iv, des_key, + des_ssh2_encrypt_blk, des_ssh2_decrypt_blk, + "des-cbc", + 8, 56, SSH_CIPHER_IS_CBC, "single-DES CBC" +}; + +static const struct ssh2_cipher ssh_des_sshcom_ssh2 = { + des_make_context, des3_free_context, des3_iv, des_key, + des_ssh2_encrypt_blk, des_ssh2_decrypt_blk, + "des-cbc@ssh.com", + 8, 56, SSH_CIPHER_IS_CBC, "single-DES CBC" +}; + +static const struct ssh2_cipher *const des3_list[] = { + &ssh_3des_ssh2_ctr, + &ssh_3des_ssh2 +}; + +const struct ssh2_ciphers ssh2_3des = { + sizeof(des3_list) / sizeof(*des3_list), + des3_list +}; + +static const struct ssh2_cipher *const des_list[] = { + &ssh_des_ssh2, + &ssh_des_sshcom_ssh2 +}; + +const struct ssh2_ciphers ssh2_des = { + sizeof(des_list) / sizeof(*des_list), + des_list +}; + +const struct ssh_cipher ssh_3des = { + des3_ssh1_make_context, des3_free_context, des3_sesskey, + des3_encrypt_blk, des3_decrypt_blk, + 8, "triple-DES inner-CBC" +}; + +static void des_sesskey(void *handle, unsigned char *key) +{ + DESContext *keys = (DESContext *) handle; + des_key(keys, key); + des_key(keys+1, key); +} + +static void des_encrypt_blk(void *handle, unsigned char *blk, int len) +{ + DESContext *keys = (DESContext *) handle; + des_cbc_encrypt(blk, len, keys); +} + +static void des_decrypt_blk(void *handle, unsigned char *blk, int len) +{ + DESContext *keys = (DESContext *) handle; + des_cbc_decrypt(blk, len, keys+1); +} + +const struct ssh_cipher ssh_des = { + des_ssh1_make_context, des3_free_context, des_sesskey, + des_encrypt_blk, des_decrypt_blk, + 8, "single-DES CBC" +}; + +#ifdef TEST_XDM_AUTH + +/* + * Small standalone utility which allows encryption and decryption of + * single cipher blocks in the XDM-AUTHORIZATION-1 style. Written + * during the rework of X authorisation for connection sharing, to + * check the corner case when xa1_firstblock matches but the rest of + * the authorisation is bogus. + * + * Just compile this file on its own with the above ifdef symbol + * predefined: + +gcc -DTEST_XDM_AUTH -o sshdes sshdes.c + + */ + +#include <stdlib.h> +void *safemalloc(size_t n, size_t size) { return calloc(n, size); } +void safefree(void *p) { return free(p); } +void smemclr(void *p, size_t size) { memset(p, 0, size); } +int main(int argc, char **argv) +{ + unsigned char words[2][8]; + unsigned char out[8]; + int i, j; + + memset(words, 0, sizeof(words)); + + for (i = 0; i < 2; i++) { + for (j = 0; j < 8 && argv[i+1][2*j]; j++) { + char x[3]; + unsigned u; + x[0] = argv[i+1][2*j]; + x[1] = argv[i+1][2*j+1]; + x[2] = 0; + sscanf(x, "%02x", &u); + words[i][j] = u; + } + } + + memcpy(out, words[0], 8); + des_decrypt_xdmauth(words[1], out, 8); + printf("decrypt(%s,%s) = ", argv[1], argv[2]); + for (i = 0; i < 8; i++) printf("%02x", out[i]); + printf("\n"); + + memcpy(out, words[0], 8); + des_encrypt_xdmauth(words[1], out, 8); + printf("encrypt(%s,%s) = ", argv[1], argv[2]); + for (i = 0; i < 8; i++) printf("%02x", out[i]); + printf("\n"); +} + +#endif |