diff options
Diffstat (limited to 'openssl/doc/apps/enc.pod')
| -rw-r--r-- | openssl/doc/apps/enc.pod | 279 |
1 files changed, 279 insertions, 0 deletions
diff --git a/openssl/doc/apps/enc.pod b/openssl/doc/apps/enc.pod new file mode 100644 index 000000000..4391c9336 --- /dev/null +++ b/openssl/doc/apps/enc.pod @@ -0,0 +1,279 @@ +=pod + +=head1 NAME + +enc - symmetric cipher routines + +=head1 SYNOPSIS + +B<openssl enc -ciphername> +[B<-in filename>] +[B<-out filename>] +[B<-pass arg>] +[B<-e>] +[B<-d>] +[B<-a>] +[B<-A>] +[B<-k password>] +[B<-kfile filename>] +[B<-K key>] +[B<-iv IV>] +[B<-p>] +[B<-P>] +[B<-bufsize number>] +[B<-nopad>] +[B<-debug>] + +=head1 DESCRIPTION + +The symmetric cipher commands allow data to be encrypted or decrypted +using various block and stream ciphers using keys based on passwords +or explicitly provided. Base64 encoding or decoding can also be performed +either by itself or in addition to the encryption or decryption. + +=head1 OPTIONS + +=over 4 + +=item B<-in filename> + +the input filename, standard input by default. + +=item B<-out filename> + +the output filename, standard output by default. + +=item B<-pass arg> + +the password source. For more information about the format of B<arg> +see the B<PASS PHRASE ARGUMENTS> section in L<openssl(1)|openssl(1)>. + +=item B<-salt> + +use a salt in the key derivation routines. This option should B<ALWAYS> +be used unless compatibility with previous versions of OpenSSL or SSLeay +is required. This option is only present on OpenSSL versions 0.9.5 or +above. + +=item B<-nosalt> + +don't use a salt in the key derivation routines. This is the default for +compatibility with previous versions of OpenSSL and SSLeay. + +=item B<-e> + +encrypt the input data: this is the default. + +=item B<-d> + +decrypt the input data. + +=item B<-a> + +base64 process the data. This means that if encryption is taking place +the data is base64 encoded after encryption. If decryption is set then +the input data is base64 decoded before being decrypted. + +=item B<-A> + +if the B<-a> option is set then base64 process the data on one line. + +=item B<-k password> + +the password to derive the key from. This is for compatibility with previous +versions of OpenSSL. Superseded by the B<-pass> argument. + +=item B<-kfile filename> + +read the password to derive the key from the first line of B<filename>. +This is for compatibility with previous versions of OpenSSL. Superseded by +the B<-pass> argument. + +=item B<-S salt> + +the actual salt to use: this must be represented as a string comprised only +of hex digits. + +=item B<-K key> + +the actual key to use: this must be represented as a string comprised only +of hex digits. If only the key is specified, the IV must additionally specified +using the B<-iv> option. When both a key and a password are specified, the +key given with the B<-K> option will be used and the IV generated from the +password will be taken. It probably does not make much sense to specify +both key and password. + +=item B<-iv IV> + +the actual IV to use: this must be represented as a string comprised only +of hex digits. When only the key is specified using the B<-K> option, the +IV must explicitly be defined. When a password is being specified using +one of the other options, the IV is generated from this password. + +=item B<-p> + +print out the key and IV used. + +=item B<-P> + +print out the key and IV used then immediately exit: don't do any encryption +or decryption. + +=item B<-bufsize number> + +set the buffer size for I/O + +=item B<-nopad> + +disable standard block padding + +=item B<-debug> + +debug the BIOs used for I/O. + +=back + +=head1 NOTES + +The program can be called either as B<openssl ciphername> or +B<openssl enc -ciphername>. + +A password will be prompted for to derive the key and IV if necessary. + +The B<-salt> option should B<ALWAYS> be used if the key is being derived +from a password unless you want compatibility with previous versions of +OpenSSL and SSLeay. + +Without the B<-salt> option it is possible to perform efficient dictionary +attacks on the password and to attack stream cipher encrypted data. The reason +for this is that without the salt the same password always generates the same +encryption key. When the salt is being used the first eight bytes of the +encrypted data are reserved for the salt: it is generated at random when +encrypting a file and read from the encrypted file when it is decrypted. + +Some of the ciphers do not have large keys and others have security +implications if not used correctly. A beginner is advised to just use +a strong block cipher in CBC mode such as bf or des3. + +All the block ciphers normally use PKCS#5 padding also known as standard block +padding: this allows a rudimentary integrity or password check to be +performed. However since the chance of random data passing the test is +better than 1 in 256 it isn't a very good test. + +If padding is disabled then the input data must be a multiple of the cipher +block length. + +All RC2 ciphers have the same key and effective key length. + +Blowfish and RC5 algorithms use a 128 bit key. + +=head1 SUPPORTED CIPHERS + + base64 Base 64 + + bf-cbc Blowfish in CBC mode + bf Alias for bf-cbc + bf-cfb Blowfish in CFB mode + bf-ecb Blowfish in ECB mode + bf-ofb Blowfish in OFB mode + + cast-cbc CAST in CBC mode + cast Alias for cast-cbc + cast5-cbc CAST5 in CBC mode + cast5-cfb CAST5 in CFB mode + cast5-ecb CAST5 in ECB mode + cast5-ofb CAST5 in OFB mode + + des-cbc DES in CBC mode + des Alias for des-cbc + des-cfb DES in CBC mode + des-ofb DES in OFB mode + des-ecb DES in ECB mode + + des-ede-cbc Two key triple DES EDE in CBC mode + des-ede Two key triple DES EDE in ECB mode + des-ede-cfb Two key triple DES EDE in CFB mode + des-ede-ofb Two key triple DES EDE in OFB mode + + des-ede3-cbc Three key triple DES EDE in CBC mode + des-ede3 Three key triple DES EDE in ECB mode + des3 Alias for des-ede3-cbc + des-ede3-cfb Three key triple DES EDE CFB mode + des-ede3-ofb Three key triple DES EDE in OFB mode + + desx DESX algorithm. + + idea-cbc IDEA algorithm in CBC mode + idea same as idea-cbc + idea-cfb IDEA in CFB mode + idea-ecb IDEA in ECB mode + idea-ofb IDEA in OFB mode + + rc2-cbc 128 bit RC2 in CBC mode + rc2 Alias for rc2-cbc + rc2-cfb 128 bit RC2 in CFB mode + rc2-ecb 128 bit RC2 in ECB mode + rc2-ofb 128 bit RC2 in OFB mode + rc2-64-cbc 64 bit RC2 in CBC mode + rc2-40-cbc 40 bit RC2 in CBC mode + + rc4 128 bit RC4 + rc4-64 64 bit RC4 + rc4-40 40 bit RC4 + + rc5-cbc RC5 cipher in CBC mode + rc5 Alias for rc5-cbc + rc5-cfb RC5 cipher in CFB mode + rc5-ecb RC5 cipher in ECB mode + rc5-ofb RC5 cipher in OFB mode + + aes-[128|192|256]-cbc 128/192/256 bit AES in CBC mode + aes-[128|192|256] Alias for aes-[128|192|256]-cbc + aes-[128|192|256]-cfb 128/192/256 bit AES in 128 bit CFB mode + aes-[128|192|256]-cfb1 128/192/256 bit AES in 1 bit CFB mode + aes-[128|192|256]-cfb8 128/192/256 bit AES in 8 bit CFB mode + aes-[128|192|256]-ecb 128/192/256 bit AES in ECB mode + aes-[128|192|256]-ofb 128/192/256 bit AES in OFB mode + +=head1 EXAMPLES + +Just base64 encode a binary file: + + openssl base64 -in file.bin -out file.b64 + +Decode the same file + + openssl base64 -d -in file.b64 -out file.bin + +Encrypt a file using triple DES in CBC mode using a prompted password: + + openssl des3 -salt -in file.txt -out file.des3 + +Decrypt a file using a supplied password: + + openssl des3 -d -salt -in file.des3 -out file.txt -k mypassword + +Encrypt a file then base64 encode it (so it can be sent via mail for example) +using Blowfish in CBC mode: + + openssl bf -a -salt -in file.txt -out file.bf + +Base64 decode a file then decrypt it: + + openssl bf -d -salt -a -in file.bf -out file.txt + +Decrypt some data using a supplied 40 bit RC4 key: + + openssl rc4-40 -in file.rc4 -out file.txt -K 0102030405 + +=head1 BUGS + +The B<-A> option when used with large files doesn't work properly. + +There should be an option to allow an iteration count to be included. + +The B<enc> program only supports a fixed number of algorithms with +certain parameters. So if, for example, you want to use RC2 with a +76 bit key or RC4 with an 84 bit key you can't use this program. + +=cut |