dh(3)

     dh(3)                  0.9.6h (2000-01-27)                  dh(3)

     NAME
          dh - Diffie-Hellman key agreement

     SYNOPSIS
           #include <openssl/dh.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, BIGNUM *pub_key, DH *dh);

           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);

           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
          These functions implement the Diffie-Hellman key agreement
          protocol.  The generation of shared DH parameters is
          described in DH_generate_parameters(3); DH_generate_key(3)
          describes 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

     Page 1                                         (printed 1/19/103)

     dh(3)                  0.9.6h (2000-01-27)                  dh(3)

     SEE ALSO
          dhparam(1), bn(3), dsa(3), err(3), rand(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)

     Page 2                                         (printed 1/19/103)