diff --git a/ctrtool/aes_keygen.c b/ctrtool/aes_keygen.c
index d8bda85..eb81bdf 100644
--- a/ctrtool/aes_keygen.c
+++ b/ctrtool/aes_keygen.c
@@ -45,14 +45,6 @@ void n128_add(const uint8_t *a, const uint8_t *b, uint8_t *out)
 		carry = sum >> 8;
 		out[i] = sum & 0xff;
 	}
-
-	while (carry != 0) {
-		for (int i = 15; i >= 0; i--) {
-			sum = out[i] + carry;
-			carry = sum >> 8;
-			out[i] = sum & 0xff;
-		}
-	}
 }
 
 /* out = a - b
@@ -77,25 +69,6 @@ void n128_sub(const uint8_t *a, const uint8_t *b, uint8_t *out)
 		// set value
 		out[i] = sum & 0xff;
 	}
-
-
-	while (carry != 0) {
-		for (int i = 15; i >= 0; i--) {
-			sum = out[i] - carry;
-
-			// check to see if anything was borrowed from next byte
-			if (out[i] < carry) {
-				sum += 0x100;
-				carry = 1;
-			}
-			else {
-				carry = 0;
-			}
-
-			out[i] = sum & 0xff;
-		}
-	}
-
 }
 
 void n128_xor(const uint8_t *a, const uint8_t *b, uint8_t *out)