1 files changed, 202 insertions, 0 deletions
diff --git a/openssl/doc/crypto/RSA_set_method.pod b/openssl/doc/crypto/RSA_set_method.pod
new file mode 100644
index 000000000..2c963d7e5
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+++ b/openssl/doc/crypto/RSA_set_method.pod
@@ -0,0 +1,202 @@
+=pod
+
+=head1 NAME
+
+RSA_set_default_method, RSA_get_default_method, RSA_set_method,
+RSA_get_method, RSA_PKCS1_SSLeay, RSA_null_method, RSA_flags,
+RSA_new_method - select RSA method
+
+=head1 SYNOPSIS
+
+ #include <openssl/rsa.h>
+
+ void RSA_set_default_method(const RSA_METHOD *meth);
+
+ RSA_METHOD *RSA_get_default_method(void);
+
+ int RSA_set_method(RSA *rsa, const RSA_METHOD *meth);
+
+ RSA_METHOD *RSA_get_method(const RSA *rsa);
+
+ RSA_METHOD *RSA_PKCS1_SSLeay(void);
+
+ RSA_METHOD *RSA_null_method(void);
+
+ int RSA_flags(const RSA *rsa);
+
+ RSA *RSA_new_method(RSA_METHOD *method);
+
+=head1 DESCRIPTION
+
+An B<RSA_METHOD> specifies the functions that OpenSSL uses for RSA
+operations. By modifying the method, alternative implementations such as
+hardware accelerators may be used. IMPORTANT: See the NOTES section for
+important information about how these RSA API functions are affected by the
+use of B<ENGINE> API calls.
+
+Initially, the default RSA_METHOD is the OpenSSL internal implementation,
+as returned by RSA_PKCS1_SSLeay().
+
+RSA_set_default_method() makes B<meth> the default method for all RSA
+structures created later. B<NB>: This is true only whilst no ENGINE has
+been set as a default for RSA, so this function is no longer recommended.
+
+RSA_get_default_method() returns a pointer to the current default
+RSA_METHOD. However, the meaningfulness of this result is dependent on
+whether the ENGINE API is being used, so this function is no longer 
+recommended.
+
+RSA_set_method() selects B<meth> to perform all operations using the key
+B<rsa>. This will replace the RSA_METHOD used by the RSA key and if the
+previous method was supplied by an ENGINE, the handle to that ENGINE will
+be released during the change. It is possible to have RSA keys that only
+work with certain RSA_METHOD implementations (eg. from an ENGINE module
+that supports embedded hardware-protected keys), and in such cases
+attempting to change the RSA_METHOD for the key can have unexpected
+results.
+
+RSA_get_method() returns a pointer to the RSA_METHOD being used by B<rsa>.
+This method may or may not be supplied by an ENGINE implementation, but if
+it is, the return value can only be guaranteed to be valid as long as the
+RSA key itself is valid and does not have its implementation changed by
+RSA_set_method().
+
+RSA_flags() returns the B<flags> that are set for B<rsa>'s current
+RSA_METHOD. See the BUGS section.
+
+RSA_new_method() allocates and initializes an RSA structure so that
+B<engine> will be used for the RSA operations. If B<engine> is NULL, the
+default ENGINE for RSA operations is used, and if no default ENGINE is set,
+the RSA_METHOD controlled by RSA_set_default_method() is used.
+
+RSA_flags() returns the B<flags> that are set for B<rsa>'s current method.
+
+RSA_new_method() allocates and initializes an B<RSA> structure so that
+B<method> will be used for the RSA operations. If B<method> is B<NULL>,
+the default method is used.
+
+=head1 THE RSA_METHOD STRUCTURE
+
+ typedef struct rsa_meth_st
+ {
+     /* name of the implementation */
+	const char *name;
+
+     /* encrypt */
+	int (*rsa_pub_enc)(int flen, unsigned char *from,
+          unsigned char *to, RSA *rsa, int padding);
+
+     /* verify arbitrary data */
+	int (*rsa_pub_dec)(int flen, unsigned char *from,
+          unsigned char *to, RSA *rsa, int padding);
+
+     /* sign arbitrary data */
+	int (*rsa_priv_enc)(int flen, unsigned char *from,
+          unsigned char *to, RSA *rsa, int padding);
+
+     /* decrypt */
+	int (*rsa_priv_dec)(int flen, unsigned char *from,
+          unsigned char *to, RSA *rsa, int padding);
+
+     /* compute r0 = r0 ^ I mod rsa->n (May be NULL for some
+                                        implementations) */
+	int (*rsa_mod_exp)(BIGNUM *r0, BIGNUM *I, RSA *rsa);
+
+     /* compute r = a ^ p mod m (May be NULL for some implementations) */
+	int (*bn_mod_exp)(BIGNUM *r, BIGNUM *a, const BIGNUM *p,
+          const BIGNUM *m, BN_CTX *ctx, BN_MONT_CTX *m_ctx);
+
+     /* called at RSA_new */
+	int (*init)(RSA *rsa);
+
+     /* called at RSA_free */
+	int (*finish)(RSA *rsa);
+
+     /* RSA_FLAG_EXT_PKEY        - rsa_mod_exp is called for private key
+      *                            operations, even if p,q,dmp1,dmq1,iqmp
+      *                            are NULL
+      * RSA_FLAG_SIGN_VER        - enable rsa_sign and rsa_verify
+      * RSA_METHOD_FLAG_NO_CHECK - don't check pub/private match
+      */
+	int flags;
+
+	char *app_data; /* ?? */
+
+     /* sign. For backward compatibility, this is used only
+      * if (flags & RSA_FLAG_SIGN_VER)
+      */
+	int (*rsa_sign)(int type, unsigned char *m, unsigned int m_len,
+           unsigned char *sigret, unsigned int *siglen, RSA *rsa);
+
+     /* verify. For backward compatibility, this is used only
+      * if (flags & RSA_FLAG_SIGN_VER)
+      */
+	int (*rsa_verify)(int type, unsigned char *m, unsigned int m_len,
+           unsigned char *sigbuf, unsigned int siglen, RSA *rsa);
+
+ } RSA_METHOD;
+
+=head1 RETURN VALUES
+
+RSA_PKCS1_SSLeay(), RSA_PKCS1_null_method(), RSA_get_default_method()
+and RSA_get_method() return pointers to the respective RSA_METHODs.
+
+RSA_set_default_method() returns no value.
+
+RSA_set_method() returns a pointer to the old RSA_METHOD implementation
+that was replaced. However, this return value should probably be ignored
+because if it was supplied by an ENGINE, the pointer could be invalidated
+at any time if the ENGINE is unloaded (in fact it could be unloaded as a
+result of the RSA_set_method() function releasing its handle to the
+ENGINE). For this reason, the return type may be replaced with a B<void>
+declaration in a future release.
+
+RSA_new_method() returns NULL and sets an error code that can be obtained
+by L<ERR_get_error(3)|ERR_get_error(3)> if the allocation fails. Otherwise
+it returns a pointer to the newly allocated structure.
+
+=head1 NOTES
+
+As of version 0.9.7, RSA_METHOD implementations are grouped together with
+other algorithmic APIs (eg. DSA_METHOD, EVP_CIPHER, etc) into B<ENGINE>
+modules. If a default ENGINE is specified for RSA functionality using an
+ENGINE API function, that will override any RSA defaults set using the RSA
+API (ie.  RSA_set_default_method()). For this reason, the ENGINE API is the
+recommended way to control default implementations for use in RSA and other
+cryptographic algorithms.
+
+=head1 BUGS
+
+The behaviour of RSA_flags() is a mis-feature that is left as-is for now
+to avoid creating compatibility problems. RSA functionality, such as the
+encryption functions, are controlled by the B<flags> value in the RSA key
+itself, not by the B<flags> value in the RSA_METHOD attached to the RSA key
+(which is what this function returns). If the flags element of an RSA key
+is changed, the changes will be honoured by RSA functionality but will not
+be reflected in the return value of the RSA_flags() function - in effect
+RSA_flags() behaves more like an RSA_default_flags() function (which does
+not currently exist).
+
+=head1 SEE ALSO
+
+L<rsa(3)|rsa(3)>, L<RSA_new(3)|RSA_new(3)>
+
+=head1 HISTORY
+
+RSA_new_method() and RSA_set_default_method() appeared in SSLeay 0.8.
+RSA_get_default_method(), RSA_set_method() and RSA_get_method() as
+well as the rsa_sign and rsa_verify components of RSA_METHOD were
+added in OpenSSL 0.9.4.
+
+RSA_set_default_openssl_method() and RSA_get_default_openssl_method()
+replaced RSA_set_default_method() and RSA_get_default_method()
+respectively, and RSA_set_method() and RSA_new_method() were altered to use
+B<ENGINE>s rather than B<RSA_METHOD>s during development of the engine
+version of OpenSSL 0.9.6. For 0.9.7, the handling of defaults in the ENGINE
+API was restructured so that this change was reversed, and behaviour of the
+other functions resembled more closely the previous behaviour. The
+behaviour of defaults in the ENGINE API now transparently overrides the
+behaviour of defaults in the RSA API without requiring changing these
+function prototypes.
+
+=cut