diff --git a/rsa/bigint.c b/rsa/bigint.c
index 5585c5a..e44a3ac 100644
--- a/rsa/bigint.c
+++ b/rsa/bigint.c
@@ -79,20 +79,20 @@ int bigint_dif(bigint_t a, bigint_t b) {
 	return 0;
 }
 
-int is_not_zero(bigint_t n) {
+int is_zero(bigint_t n) {
 	for (size_t i = 0; i < n.len; i++) {
 		if (n.data[i]) {
-			return 1;
+			return 0;
 		}
 	}
-	return 0;
+	return 1;
 }
 
 // TODO check opti
 void bigint_substraction(bigint_t a, bigint_t b, bigint_t borrow, bigint_t y) {
 	//my_memcpy(borrow.data, b.data, b.len * sizeof(uint32_t));
 	my_memcpy(y.data, b.data, b.len * sizeof(uint32_t));
-	while (is_not_zero(y)) {
+	while (!is_zero(y)) {
 		for (size_t i = 0; i < a.len; i++) {
 			borrow.data[i] = ~a.data[i] & y.data[i];
 			a.data[i] = a.data[i] ^ y.data[i];
@@ -117,7 +117,7 @@ void custom_bigint_modulo(bigint_t a, bigint_t b, bigint_t result, bigint_t mod,
 			bigint_substraction(result, mod, borrow_sub, y_sub);
 		}
 	}
-	while (bigint_cmp(result, b) > 0) {
+	while (bigint_cmp(result, b) > -1) {
 		bigint_substraction(result, b, borrow_sub, y_sub);
 	}
 }
@@ -241,14 +241,26 @@ void bulk_destroy(bigint_t x, bigint_t y, bigint_t n, bigint_t d, bigint_t two,
 	bigint_destroy(n_minus_one);
 }
 
-bigint_t bigint_prime(size_t len) {
+int prime_division(bigint_t *primes, bigint_t n, bigint_t mod, bigint_t custom2, bigint_t borrow_sub, bigint_t y_sub) {
+	//printf("testing %u\n", n.data[0]);
+	bigint_set_zeros(mod);
+	for (int i = 0; i < 3245; i++) {
+		mod.data[0] = primes[i].data[0];
+		custom_bigint_modulo(n, primes[i], custom2, mod, borrow_sub, y_sub);
+		//printf("i %d prime %d mod %d\n", i, primes[i].data[0], custom2.data[0]);
+		if (is_zero(custom2)) {
+			return 1;
+		}
+	}
+	return 0;
+}
+bigint_t bigint_prime(size_t len, bigint_t *primes) {
 	size_t my_size = len * 2;
 
 	bigint_t n = bigint_zero(my_size);
 
 	bigint_set_random_bytes(n, len);
 	bigint_set_msb_and_lsb_to_one(n, len);
-
 	bigint_t mod = bigint_clone(n);
 	bigint_t borrow_sub = bigint_clone(n);
 	bigint_t y_sub = bigint_clone(n);
@@ -266,6 +278,14 @@ bigint_t bigint_prime(size_t len) {
 	bigint_t custom2 = bigint_zero(my_size);
 	bigint_t *b_tool = (bigint_t *)protected_malloc(32 * sizeof(bigint_t));
 
+
+	if (prime_division(primes, n, mod, custom2, borrow_sub, y_sub)) {
+		bulk_destroy(x, y, n, d, custom, custom2, mod, borrow_sub);
+		bigint_destroy(y_sub);		
+		return bigint_prime(len, primes);
+	}
+	memcpy(mod.data, n.data, n.len * sizeof(uint32_t));
+
 	for (int i = 0; i < 32; i++) {
 		b_tool[i] = bigint_zero(my_size * 2);
 	}
@@ -301,7 +321,7 @@ bigint_t bigint_prime(size_t len) {
 					bigint_destroy(b_tool[i]);
 				}
 				free(b_tool);
-				return bigint_prime(len);
+				return bigint_prime(len, primes);
 			}
 			bigint_destroy(x);
 			x = bigint_clone(y);
@@ -318,7 +338,7 @@ bigint_t bigint_prime(size_t len) {
 				bigint_destroy(b_tool[i]);
 			}
 			free(b_tool);
-			return bigint_prime(len);
+			return bigint_prime(len, primes);
 		}
 	}
 	bulk_destroy(x, y, custom, d, two, one, n_minus_two, n_minus_one);
diff --git a/rsa/rsa.c b/rsa/rsa.c
index 94b47eb..e83421e 100644
--- a/rsa/rsa.c
+++ b/rsa/rsa.c
@@ -1,15 +1,15 @@
 #include "rsa.h"
 
-rsa_t rsa_init(size_t len) {
+rsa_t rsa_init(size_t len, bigint_t *primes) {
 	rsa_t rsa;
 
 	printf("Generating two primes of length %d bits\n", RSA_BLOCK_SIZE / 2);
 	//printf("Generating p...\n");
-	rsa.p = bigint_prime(len / 2);
+	rsa.p = bigint_prime(len / 2, primes);
 	printf("p = %lu\n", ((uint64_t)rsa.p.data[1] << 32) + (uint64_t)rsa.p.data[0]);
 	//printf("p = %u\n", rsa.p.data[0]);
 	//printf("Generating q...\n");
-	rsa.q = bigint_prime(len / 2);
+	rsa.q = bigint_prime(len / 2, primes);
 	printf("q = %lu\n", ((uint64_t)rsa.q.data[1] << 32) + (uint64_t)rsa.q.data[0]);
 	//printf("q = %u\n", rsa.q.data[0]);
 
@@ -19,11 +19,28 @@ rsa_t rsa_init(size_t len) {
 
 rsa_t rsa_generate_keys(size_t block_size) {
 	size_t len = block_size / sizeof(uint32_t) / 8;
-	rsa_t rsa = rsa_init(len);
+	bigint_t *primes = (bigint_t *)protected_malloc(3245 * sizeof(bigint_t));
+	for (int i = 0; i < 3245; i++) {
+		primes[i] = bigint_zero(len);
+	}
+	int fd = open("primes.0000", O_RDONLY);
+	char *buf = (char *)malloc(21290 * sizeof(char));
+	int ret = read(fd, buf, 21290);
+	char *tok = strtok(buf, "\n");
+	int i = 0;
+	while (tok) {
+		primes[i].data[0] = (uint32_t)atoi(tok);
+		tok = strtok(NULL, "\n");
+		i += 1;
+	}
+	printf("ret %d\n", ret);
+
+
+	rsa_t rsa = rsa_init(len, primes);
 	bigint_destroy(rsa.p);
 	bigint_destroy(rsa.q);
 	for (int i = 0; i < 18; i++) {
-		bigint_t p = bigint_prime(len / 2);
+		bigint_t p = bigint_prime(len / 2, primes);
 		printf("%lu\n", ((uint64_t)p.data[1] << 32) + (uint64_t)p.data[0]);
 		bigint_destroy(p);
 	}
diff --git a/rsa/rsa.h b/rsa/rsa.h
index ce55a92..4a0661e 100644
--- a/rsa/rsa.h
+++ b/rsa/rsa.h
@@ -9,7 +9,7 @@
 #include <unistd.h>
 #include <string.h>
 
-#define RSA_BLOCK_SIZE 256
+#define RSA_BLOCK_SIZE 256 
 
 typedef struct bigint_s {
 	uint32_t *data;
@@ -33,7 +33,7 @@ void bigint_bitwise_left_shift(bigint_t n);
 void bigint_bitwise_right_shift(bigint_t n);
 void bigint_decrement(bigint_t n);
 int64_t bigint_cmp(bigint_t a, bigint_t b);
-bigint_t bigint_prime(size_t len);
+bigint_t bigint_prime(size_t len, bigint_t *primes);
 void bigint_print(bigint_t n);
 bigint_t bigint_new(size_t len);
 bigint_t bigint_zero(size_t len);