opnsense-src/secure/lib/libcrypto/man/dh.3

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.\" ======================================================================
.\"
.IX Title "DH 1"
.TH DH 1 "perl v5.6.1" "2000-04-13" "User Contributed Perl Documentation"
.UC
.SH "NAME"
dh \- Diffie-Hellman key agreement
.SH "SYNOPSIS"
.IX Header "SYNOPSIS"
.Vb 1
\& #include <openssl/dh.h>
.Ve
.Vb 2
\& DH *   DH_new(void);
\& void   DH_free(DH *dh);
.Ve
.Vb 1
\& int    DH_size(DH *dh);
.Ve
.Vb 3
\& DH *   DH_generate_parameters(int prime_len, int generator,
\&                void (*callback)(int, int, void *), void *cb_arg);
\& int    DH_check(DH *dh, int *codes);
.Ve
.Vb 2
\& int    DH_generate_key(DH *dh);
\& int    DH_compute_key(unsigned char *key, BIGNUM *pub_key, DH *dh);
.Ve
.Vb 5
\& 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);
.Ve
.Vb 4
\& 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);
.Ve
.Vb 2
\& DH *   d2i_DHparams(DH **a, unsigned char **pp, long length);
\& int    i2d_DHparams(DH *a, unsigned char **pp);
.Ve
.Vb 2
\& int    DHparams_print_fp(FILE *fp, DH *x);
\& int    DHparams_print(BIO *bp, DH *x);
.Ve
.SH "DESCRIPTION"
.IX Header "DESCRIPTION"
These functions implement the Diffie-Hellman key agreement protocol.
The generation of shared \s-1DH\s0 parameters is described in
DH_generate_parameters(3); DH_generate_key(3) describes how
to perform a key agreement.
.PP
The \fB\s-1DH\s0\fR structure consists of several \s-1BIGNUM\s0 components.
.PP
.Vb 9
\& 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
.Ve
.SH "SEE ALSO"
.IX Header "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)