2 files changed, 88 insertions, 1 deletions

diff --git a/lib/lib5.c b/lib/lib5.c
index 04c7806..f87014c 100644
--- a/lib/lib5.c
+++ b/lib/lib5.c
@@ -215,7 +215,7 @@ void srp_compute_x(BIGNUM *salt, unsigned char *password, char *sha1_hash)
 	memcpy(&to_hash[BN_num_bytes(salt)-1], password, strlen(password));
 
 	SHA1Reset(&sha1);
-	SHA1Input(&sha1, to_hash, strlen(to_hash));
+	SHA1Input(&sha1, to_hash, strlen(password)+BN_num_bytes(salt));
 	SHA1Result(&sha1);
 	memcpy(sha1_hash, &(sha1.Message_Digest), 20);
 }
@@ -248,6 +248,17 @@ void srp_server_send1(struct srp_context *srpc)
 	BN_mod_add(srpc->B, t, t2, srpc->N, ctx);
 }
 
+void ssrp_server_send1(struct srp_context *srpc)
+{
+	BN_pseudo_rand(srpc->b, 1024, -1, -1);
+	BN_mod_exp(srpc->B, srpc->g, srpc->b, srpc->N, ctx);
+}
+
+void ssrp_compute_uH(struct srp_context *srpc)
+{
+	BN_pseudo_rand(srpc->u, 1024, -1, -1);
+}
+
 void srp_compute_uH(struct srp_context *srpc)
 {
 	SHA1Context sha1;
@@ -309,6 +320,31 @@ void srp_client_prepare_k(struct srp_context *srpc, char *password)
 	memcpy(srpc->client_K, &(sha1.Message_Digest), 20);
 }
 
+void ssrp_client_prepare_k(struct srp_context *srpc, char *password)
+{
+	SHA1Context sha1;
+	BIGNUM *x = BN_new();
+	char K[20];
+	char sha1_hash[20];
+
+	srp_compute_x(srpc->salt, password, sha1_hash);
+	BN_bin2bn(sha1_hash, 20, x);
+
+	BIGNUM *S = BN_new();
+	BIGNUM *tmp = BN_new();
+
+	BN_mod_mul(tmp, srpc->u, x, srpc->N, ctx);
+	BN_mod_add(tmp, tmp, srpc->a, srpc->N, ctx);
+	BN_mod_exp(S, srpc->B, tmp, srpc->N, ctx);
+
+	char *s_str = malloc(BN_num_bytes(S));
+	BN_bn2bin(S, s_str);
+	SHA1Reset(&sha1);
+	SHA1Input(&sha1, s_str, BN_num_bytes(S));
+	SHA1Result(&sha1);
+	memcpy(srpc->client_K, &(sha1.Message_Digest), 20);
+}
+
 void srp_server_prepare_k(struct srp_context *srpc)
 {
 	BIGNUM *S = BN_new();
@@ -684,3 +720,49 @@ double nth_root_wr(double x, int n)
 	return r;
 }
 
+
+void ssrp_dictionary_attack(struct srp_context *srpc)
+{
+
+	// in srpc.client_K is the hash given by the client
+	// attack with all passwords in task38.dictionary
+	size_t line_len = 1024;
+	char *line = NULL;
+	FILE *fp = fopen("task38.dictionary", "r");
+	int read = 0;
+	char sha1_hash[20];
+	char cK[40];
+	SHA1Context sha1;
+	BIGNUM *x = BN_new();
+	BIGNUM *S= BN_new();
+
+	while((read = getline(&line, &line_len, fp)) != -1) {
+		BN_zero(x);
+		BN_zero(S);
+		memset(sha1_hash, 0, 20);
+		line[read-1] = 0;	
+		printf("try password: %s\n", line);
+		srp_compute_x(srpc->salt, line, sha1_hash);
+		BN_bin2bn(sha1_hash, 20, x);
+		BN_mod_exp(S, srpc->g, x, srpc->N, ctx);
+		BN_mod_exp(S, S, srpc->u, srpc->N, ctx);
+		BN_mod_mul(S, S, srpc->A, srpc->N, ctx);
+		BN_mod_exp(S, S, srpc->b, srpc->N, ctx);
+
+		char *s_str = malloc(BN_num_bytes(S));
+		memset(s_str, 0, BN_num_bytes(S));
+		BN_bn2bin(S, s_str);
+		SHA1Reset(&sha1);
+		SHA1Input(&sha1, s_str, BN_num_bytes(S));
+		SHA1Result(&sha1);
+		memcpy(sha1_hash, &(sha1.Message_Digest), 20);
+		if(strncmp(sha1_hash, srpc->client_K, 20) == 0) {
+			printf("found password: %s\n", line);
+			hex_binary_to_string(sha1_hash, cK, 20);
+			printf("hash is: %s\n", cK);
+			free(s_str);
+			break;
+		}
+		free(s_str);
+	}
+}
diff --git a/lib/lib5.h b/lib/lib5.h
index bf71802..0c2571f 100644
--- a/lib/lib5.h
+++ b/lib/lib5.h
@@ -117,4 +117,9 @@ void srp_client_prepare_k(struct srp_context *srpc, char *password);
 void srp_server_prepare_k(struct srp_context *srpc);
 void srp_context_init(struct srp_context *s);
 void srp_client_s_0_prepare_k(struct srp_context *srpc);
+void ssrp_compute_uH(struct srp_context *srpc);
+void ssrp_server_send1(struct srp_context *srpc);
+void ssrp_client_prepare_k(struct srp_context *srpc, char *password);
+void srp_server_prepare_k(struct srp_context *srpc);
+void ssrp_dictionary_attack(struct srp_context *srpc);
 #endif