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author | William Joye <wjoye@cfa.harvard.edu> | 2017-05-02 16:41:35 (GMT) |
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committer | William Joye <wjoye@cfa.harvard.edu> | 2017-05-02 16:41:35 (GMT) |
commit | 3d328008deedc58cd7a11c79063cefa7d662d4fc (patch) | |
tree | cb41a048885ce7b493f406360cf5f6edf689c468 /openssl/doc/crypto/RSA_set_method.pod | |
parent | 0a2b8b8e0bc2e91a9f10659b30e2e4f5b79ce692 (diff) | |
download | blt-3d328008deedc58cd7a11c79063cefa7d662d4fc.zip blt-3d328008deedc58cd7a11c79063cefa7d662d4fc.tar.gz blt-3d328008deedc58cd7a11c79063cefa7d662d4fc.tar.bz2 |
inital commit
Diffstat (limited to 'openssl/doc/crypto/RSA_set_method.pod')
-rw-r--r-- | openssl/doc/crypto/RSA_set_method.pod | 206 |
1 files changed, 206 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 0000000..0ef0781 --- /dev/null +++ b/openssl/doc/crypto/RSA_set_method.pod @@ -0,0 +1,206 @@ +=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, + const unsigned char *m, unsigned int m_length, + unsigned char *sigret, unsigned int *siglen, const RSA *rsa); + /* verify. For backward compatibility, this is used only + * if (flags & RSA_FLAG_SIGN_VER) + */ + int (*rsa_verify)(int dtype, + const unsigned char *m, unsigned int m_length, + const unsigned char *sigbuf, unsigned int siglen, + const RSA *rsa); + /* keygen. If NULL builtin RSA key generation will be used */ + int (*rsa_keygen)(RSA *rsa, int bits, BIGNUM *e, BN_GENCB *cb); + + } 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 |