lib/libssh2
1
0
Fork 0
mirror of https://github.com/libssh2/libssh2.git synced 2025-11-20 02:42:09 +03:00
Code Activity

Implement Diffie-Hellman computations in crypto backends. (#149)

Browse Source 
Not all backends feature the low level API needed to compute a Diffie-Hellman
secret, but some of them directly implement Diffie-Hellman support with opaque
private data. The later approach is now generalized and backends are
responsible for all Diffie Hellman computations.
As a side effect, procedures/macros _libssh2_bn_rand and _libssh2_bn_mod_exp
are no longer needed outside the backends.
This commit is contained in:
monnerat
2016-11-27 19:39:00 +01:00
committed by Alexander Lamaison
parent 5abceec571
commit f7daf3185a
10 changed files with 215 additions and 96 deletions
Download Patch File Download Diff File Expand all files Collapse all files

41
src/mbedtls.c
View File

@@ -203,7 +203,7 @@ _libssh2_mbedtls_bignum_init(void)
return bignum;
}
int
static int
_libssh2_mbedtls_bignum_random(_libssh2_bn *bn, int bits, int top, int bottom)
{
size_t len;
@@ -603,4 +603,43 @@ void _libssh2_init_aes_ctr(void)
{
/* no implementation */
}
/*******************************************************************/
/*
* mbedTLS backend: Diffie-Hellman functions
*/
void
_libssh2_dh_init(_libssh2_dh_ctx *dhctx)
{
*dhctx = _libssh2_mbedtls_bignum_init(); /* Random from client */
}
int
_libssh2_dh_key_pair(_libssh2_dh_ctx *dhctx, _libssh2_bn *public,
_libssh2_bn *g, _libssh2_bn *p, int group_order)
{
/* Generate x and e */
_libssh2_mbedtls_bignum_random(*dhctx, group_order * 8 - 1, 0, -1);
mbedtls_mpi_exp_mod(public, g, *dhctx, p, NULL);
return 0;
}
int
_libssh2_dh_secret(_libssh2_dh_ctx *dhctx, _libssh2_bn *secret,
_libssh2_bn *f, _libssh2_bn *p)
{
/* Compute the shared secret */
mbedtls_mpi_exp_mod(secret, f, *dhctx, p, NULL);
return 0;
}
void
_libssh2_dh_dtor(_libssh2_dh_ctx *dhctx)
{
mbedtls_mpi_free(*dhctx);
*dhctx = NULL;
}
#endif /* LIBSSH2_MBEDTLS */