diff options
Diffstat (limited to 'doc/crypto/DSA_set_method.pod')
-rw-r--r-- | doc/crypto/DSA_set_method.pod | 91 |
1 files changed, 58 insertions, 33 deletions
diff --git a/doc/crypto/DSA_set_method.pod b/doc/crypto/DSA_set_method.pod index 36a1052d27..bc3cfb1f0a 100644 --- a/doc/crypto/DSA_set_method.pod +++ b/doc/crypto/DSA_set_method.pod @@ -2,7 +2,7 @@ =head1 NAME -DSA_set_default_openssl_method, DSA_get_default_openssl_method, +DSA_set_default_method, DSA_get_default_method, DSA_set_method, DSA_new_method, DSA_OpenSSL - select DSA method =head1 SYNOPSIS @@ -10,11 +10,11 @@ DSA_set_method, DSA_new_method, DSA_OpenSSL - select DSA method #include <openssl/dsa.h> #include <openssl/engine.h> - void DSA_set_default_openssl_method(DSA_METHOD *meth); + void DSA_set_default_method(const DSA_METHOD *meth); - DSA_METHOD *DSA_get_default_openssl_method(void); + const DSA_METHOD *DSA_get_default_method(void); - int DSA_set_method(DSA *dsa, ENGINE *engine); + int DSA_set_method(DSA *dsa, const DSA_METHOD *meth); DSA *DSA_new_method(ENGINE *engine); @@ -24,26 +24,35 @@ DSA_set_method, DSA_new_method, DSA_OpenSSL - select DSA method A B<DSA_METHOD> specifies the functions that OpenSSL uses for DSA operations. By modifying the method, alternative implementations -such as hardware accelerators may be used. - -Initially, the default is to use the OpenSSL internal implementation. -DSA_OpenSSL() returns a pointer to that method. - -DSA_set_default_openssl_method() makes B<meth> the default method for -all DSA structures created later. B<NB:> This is true only whilst the -default engine for DSA operations remains as "openssl". ENGINEs -provide an encapsulation for implementations of one or more algorithms at a -time, and all the DSA functions mentioned here operate within the scope -of the default "openssl" engine. - -DSA_get_default_openssl_method() returns a pointer to the current default -method for the "openssl" engine. - -DSA_set_method() selects B<engine> for all operations using the structure B<dsa>. - -DSA_new_method() allocates and initializes a DSA structure so that -B<engine> will be used for the DSA operations. If B<engine> is NULL, -the default engine for DSA operations is used. +such as hardware accelerators may be used. IMPORTANT: See the NOTES section for +important information about how these DSA API functions are affected by the use +of B<ENGINE> API calls. + +Initially, the default DSA_METHOD is the OpenSSL internal implementation, +as returned by DSA_OpenSSL(). + +DSA_set_default_method() makes B<meth> the default method for all DSA +structures created later. B<NB>: This is true only whilst no ENGINE has +been set as a default for DSA, so this function is no longer recommended. + +DSA_get_default_method() returns a pointer to the current default +DSA_METHOD. However, the meaningfulness of this result is dependant on +whether the ENGINE API is being used, so this function is no longer +recommended. + +DSA_set_method() selects B<meth> to perform all operations using the key +B<rsa>. This will replace the DSA_METHOD used by the DSA 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 DSA keys that only +work with certain DSA_METHOD implementations (eg. from an ENGINE module +that supports embedded hardware-protected keys), and in such cases +attempting to change the DSA_METHOD for the key can have unexpected +results. + +DSA_new_method() allocates and initializes a DSA structure so that B<engine> +will be used for the DSA operations. If B<engine> is NULL, the default engine +for DSA operations is used, and if no default ENGINE is set, the DSA_METHOD +controlled by DSA_set_default_method() is used. =head1 THE DSA_METHOD STRUCTURE @@ -89,18 +98,29 @@ struct =head1 RETURN VALUES -DSA_OpenSSL() and DSA_get_default_openssl_method() return pointers to the -respective B<DSA_METHOD>s. +DSA_OpenSSL() and DSA_get_default_method() return pointers to the respective +B<DSA_METHOD>s. -DSA_set_default_openssl_method() returns no value. +DSA_set_default_method() returns no value. -DSA_set_method() returns non-zero if the ENGINE associated with B<dsa> -was successfully changed to B<engine>. +DSA_set_method() returns non-zero if the provided B<meth> was successfully set as +the method for B<dsa> (including unloading the ENGINE handle if the previous +method was supplied by an ENGINE). DSA_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, DSA_METHOD implementations are grouped together with other +algorithmic APIs (eg. RSA_METHOD, EVP_CIPHER, etc) in B<ENGINE> modules. If a +default ENGINE is specified for DSA functionality using an ENGINE API function, +that will override any DSA defaults set using the DSA API (ie. +DSA_set_default_method()). For this reason, the ENGINE API is the recommended way +to control default implementations for use in DSA and other cryptographic +algorithms. + =head1 SEE ALSO L<dsa(3)|dsa(3)>, L<DSA_new(3)|DSA_new(3)> @@ -110,9 +130,14 @@ L<dsa(3)|dsa(3)>, L<DSA_new(3)|DSA_new(3)> DSA_set_default_method(), DSA_get_default_method(), DSA_set_method(), DSA_new_method() and DSA_OpenSSL() were added in OpenSSL 0.9.4. -DSA_set_default_openssl_method() and DSA_get_default_openssl_method() -replaced DSA_set_default_method() and DSA_get_default_method() respectively, -and DSA_set_method() and DSA_new_method() were altered to use B<ENGINE>s -rather than B<DSA_METHOD>s during development of OpenSSL 0.9.6. +DSA_set_default_openssl_method() and DSA_get_default_openssl_method() replaced +DSA_set_default_method() and DSA_get_default_method() respectively, and +DSA_set_method() and DSA_new_method() were altered to use B<ENGINE>s rather than +B<DSA_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 DSA API without +requiring changing these function prototypes. =cut |