dh: added a dh bignum implementation based on openssl

1 files changed, 50 insertions, 0 deletions

diff --git a/lib/lib5.c b/lib/lib5.c
index 722cc46..60b0836 100644
--- a/lib/lib5.c
+++ b/lib/lib5.c
@@ -98,6 +98,56 @@ void do_dh_key_exchange(struct dh_param *dh)
 	dh_get_session_key(dh);
 }
 
+void dh_init_bignum(struct dh_param_bignum *dh)
+{
+	dh->A = BN_new();
+	dh->B = BN_new();
+	dh->a = BN_new();
+	dh->b = BN_new();
+	dh->p = BN_new();
+	dh->g = BN_new();
+	dh->s1 = BN_new();
+	dh->s2 = BN_new();
+	unsigned char *p =
+		"ffffffffffffffffc90fdaa22168c234c4c6628b80dc1cd129024"
+		"e088a67cc74020bbea63b139b22514a08798e3404ddef9519b3cd"
+		"3a431b302b0a6df25f14374fe1356d6d51c245e485b576625e7ec"
+		"6f44c42e9a637ed6b0bff5cb6f406b7edee386bfb5a899fa5ae9f"
+		"24117c4b1fe649286651ece45b3dc2007cb8a163bf0598da48361"
+		"c55d39a69163fa8fd24cf5f83655d23dca3ad961c62f356208552"
+		"bb9ed529077096966d670c354e4abc9804f1746c08ca237327fff"
+		"fffffffffffff";
+	unsigned char *res = malloc(strlen(p));
+	int len_dec = decode_hex_string(p, res);
+	BN_bin2bn(res, len_dec, dh->p);
+	BN_set_word(dh->g, 2);
+}
+void dh_generate_secret_keys_bignum(struct dh_param_bignum *dh)
+{
+	BN_pseudo_rand(dh->a, 8000, -1, -1);
+	BN_pseudo_rand(dh->b, 8000, -1, -1);
+}
+
+void dh_generate_public_keys_bignum(struct dh_param_bignum *dh)
+{
+	BN_mod_exp(dh->A, dh->g, dh->a, dh->p, ctx);
+	BN_mod_exp(dh->B, dh->g, dh->b, dh->p, ctx);
+}
+
+void dh_get_session_key_bignum(struct dh_param_bignum *dh)
+{
+	BN_mod_exp(dh->s1, dh->B, dh->a, dh->p, ctx);
+	BN_mod_exp(dh->s2, dh->A, dh->b, dh->p, ctx);
+}
+
+void do_dh_key_exchange_bignum(struct dh_param_bignum *dh)
+{
+	dh_init_bignum(dh);
+	dh_generate_secret_keys_bignum(dh);
+	dh_generate_public_keys_bignum(dh);
+	dh_get_session_key_bignum(dh);
+}
+
 void sha1_key_from_dh(struct dh_param *dh, unsigned char *key)
 {
 	char *s1_char;