diff options
author | Ulf Möller <ulf@openssl.org> | 2000-01-22 20:05:23 +0000 |
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committer | Ulf Möller <ulf@openssl.org> | 2000-01-22 20:05:23 +0000 |
commit | 4486d0cd7a715aed7ca3728aa24413d91666bb68 (patch) | |
tree | 36342c32d8bd73c31ea5e3d33e9ee7796bab873c /doc/crypto/DH_set_method.pod | |
parent | 09483c58e3b21841d2761ce90b1f12b24f814881 (diff) |
Document the DH library, and make some minor changes along the way.
Diffstat (limited to 'doc/crypto/DH_set_method.pod')
-rw-r--r-- | doc/crypto/DH_set_method.pod | 99 |
1 files changed, 99 insertions, 0 deletions
diff --git a/doc/crypto/DH_set_method.pod b/doc/crypto/DH_set_method.pod new file mode 100644 index 0000000000..b50bf42a56 --- /dev/null +++ b/doc/crypto/DH_set_method.pod @@ -0,0 +1,99 @@ +=pod + +=head1 NAME + +DH_set_default_method, DH_get_default_method, DH_set_method, +DH_new_method, DH_OpenSSL - Select RSA method + +=head1 SYNOPSIS + + #include <openssl/dh.h> + + void DH_set_default_method(DH_METHOD *meth); + + DH_METHOD *DH_get_default_method(void); + + DH_METHOD *DH_set_method(DH *dh, DH_METHOD *meth); + + DH *DH_new_method(DH_METHOD *meth); + + DH_METHOD *DH_OpenSSL(void); + +=head1 DESCRIPTION + +A B<DH_METHOD> specifies the functions that OpenSSL uses for Diffie-Hellman +operations. By modifying the method, alternative implementations +such as hardware accelerators may be used. + +Initially, the default is to use the OpenSSL internal implementation. +DH_OpenSSL() returns a pointer to that method. + +DH_set_default_method() makes B<meth> the default method for all B<DH> +structures created later. + +DH_get_default_method() returns a pointer to the current default +method. + +DH_set_method() selects B<meth> for all operations using the structure B<dh>. + +DH_get_method() returns a pointer to the method currently selected +for B<dh>. + +DH_new_method() allocates and initializes a B<DH> structure so that +B<method> will be used for the DH operations. If B<method> is B<NULL>, +the default method is used. + +=head1 THE DH_METHOD STRUCTURE + + typedef struct dh_meth_st + { + /* name of the implementation */ + const char *name; + + /* generate private and public DH values for key agreement */ + int (*generate_key)(DH *dh); + + /* compute shared secret */ + int (*compute_key)(unsigned char *key, BIGNUM *pub_key, DH *dh); + + /* compute r = a ^ p mod m. May be NULL */ + int (*bn_mod_exp)(DH *dh, BIGNUM *r, BIGNUM *a, const BIGNUM *p, + const BIGNUM *m, BN_CTX *ctx, + BN_MONT_CTX *m_ctx); + + /* called at DH_new */ + int (*init)(DH *dh); + + /* called at DH_free */ + int (*finish)(DH *dh); + + int flags; + + char *app_data; /* ?? */ + + } DH_METHOD; + +=head1 RETURN VALUES + +DH_OpenSSL(), DH_get_default_method() and DH_get_method() return +pointers to the respective B<DH_METHOD>s. + +DH_set_default_method() returns no value. + +DH_set_method() returns a pointer to the B<DH_METHOD> previously +associated with B<dh>. + +DH_new_method() returns B<NULL> and sets an error code that can be +obtained by ERR_get_error(3) if the allocation fails. Otherwise it +returns a pointer to the newly allocated structure. + +=head1 SEE ALSO + +dh(3), DH_new(3) + +=head1 HISTORY + +DH_set_default_method(), DH_get_default_method(), DH_set_method(), +DH_new_method() and DH_OpenSSL() were added in OpenSSL 0.9.4. + +=cut |