diff --git a/set1/challenge3_xor_cipher/src/main.zig b/set1/challenge3_xor_cipher/src/main.zig
index 53ea31c..a3ff6d4 100644
--- a/set1/challenge3_xor_cipher/src/main.zig
+++ b/set1/challenge3_xor_cipher/src/main.zig
@@ -52,7 +52,7 @@ pub fn main() anyerror!void {
         var bestkey: u8 = 0;
         var bestscore: u32 = 0;
         var key: u8 = 0;
-        while (true) {
+        while (true) : (key += 1) {
             decrypt(plaintext, ciphertext, key);
             const s = score(plaintext);
             if (s > bestscore) {
@@ -60,7 +60,7 @@ pub fn main() anyerror!void {
                 bestscore = s;
             }
             key +%= 1;
-            if (key == 0) {
+            if (key == std.math.maxInt(u8)) {
                 break;
             }
         }
diff --git a/set1/challenge4_detect_xor/src/main.zig b/set1/challenge4_detect_xor/src/main.zig
index a7dd342..ff7ec4b 100644
--- a/set1/challenge4_detect_xor/src/main.zig
+++ b/set1/challenge4_detect_xor/src/main.zig
@@ -54,7 +54,7 @@ pub fn main() anyerror!void {
         var plaintext = try allocator.alloc(u8, ciphertext.len);
         defer allocator.free(plaintext);
         var key: u8 = 0;
-        while (true) {
+        while (true) : (key += 1) {
             decrypt(plaintext, ciphertext, key);
             const s = score(plaintext);
             if (s > bestscore) {
@@ -62,8 +62,7 @@ pub fn main() anyerror!void {
                 std.mem.copy(u8, bestplaintext.items, plaintext);
                 bestscore = s;
             }
-            key +%= 1;
-            if (key == 0) {
+            if (key == std.math.maxInt(u8)) {
                 break;
             }
         }