NAME    [Toc]    [Back]

       dh - Diffie-Hellman key agreement

SYNOPSIS    [Toc]    [Back]

       #include <openssl/dh.h> #include <openssl/engine.h>

       DH * DH_new(
               void ); void DH_free(
               DH *dh ); int   DH_size(
               DH *dh ); DH * DH_generate_parameters(
               int prime_len,
               int generator,
               void (*callback)(int, int, void *),
               void *(cb_arg),
               int    DH_check  (DH  *dh,  int  *codes)  ); int
       DH_generate_key(
               DH *dh ); int   DH_compute_key(
               unsigned char *key,
               IGNUM *pub_key,
               B,
               DH *dh ); void DH_set_default_openssl_method(
               DH_METHOD        *meth        );         DH_METHOD
       *DH_get_default_openssl_method(
               void ); int   DH_set_method(
               DH *dh,
               ENGINE *engine ); DH *DH_new_method(
               ENGINE *engine ); DH_METHOD *DH_OpenSSL(
               void ); int   DH_get_ex_new_index(
               long argl,
               char *argp,
               int (*new_func)(),
               int (*dup_func)()),
               void (*free_func)() ); int   DH_set_ex_data(
               DH *d,
               int idx,
               char *arg ); char *DH_get_ex_data(
               DH *d,
               int idx ); DH * d2i_DHparams(
               DH **a,
               unsigned char **pp,
               long length ); int   i2d_DHparams(
               DH *a,
               unsigned char **pp ); int   DHparams_print_fp(
               FILE *fp,
               DH *x ); int   DHparams_print(
               BIO *bp,
               DH *x );

DESCRIPTION    [Toc]    [Back]

       These functions implement the Diffie-Hellman key agreement
       protocol.  The  generation  of  shared  DH  parameters  is
       described  in  DH_generate_parameters(3).   See  DH_generate_key(3) for a description  of  how  to  perform  a  key
       agreement.

       The DH structure consists of several BIGNUM components:
        struct
               {
               BIGNUM *p;       // prime number (shared)
               BIGNUM *g;       // generator of Z_p (shared)
               BIGNUM *priv_key;     // private DH value x
               BIGNUM *pub_key; // public DH value g^x
               // ...
               };
        DH

SEE ALSO    [Toc]    [Back]

       Commands: dhparam(1)

       Functions:  bn(3),  dsa(3),  err(3),  rand_ssl(3), rsa(3),
       DH_set_method(3),    DH_new(3),    DH_get_ex_new_index(3),
       DH_generate_parameters(3),              DH_compute_key(3),
       d2i_DHparams(3), RSA_print(3)



                                                            dh(3)