NAME    [Toc]    [Back]

       dh - Diffie-Hellman key agreement

LIBRARY    [Toc]    [Back]

       libcrypto, -lcrypto

SYNOPSIS    [Toc]    [Back]

        #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    [Toc]    [Back]

       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

SEE ALSO    [Toc]    [Back]

       openssl_dhparam(1), openssl_bn(3), openssl_dsa(3),
       openssl_err(3), openssl_rand(3), openssl_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)



2000-07-22                    0.9.6g                        dh(3)