fix padding

Author: jialinli98

.github/workflows/test.yml

@@ -8,7 +8,7 @@ on:
 
 env:
   CARGO_TERM_COLOR: always
-  MINIMUM_NOIR_VERSION: v1.0.0-beta.13
+  MINIMUM_NOIR_VERSION: v1.0.0-beta.9
 
 jobs:
   noir-version-list:

src/keccak256.nr

@@ -36,7 +36,13 @@ pub fn keccak256<let N: u32>(input: [u8; N], message_size: u32) -> [u8; 32] {
     let real_blocks_bytes = real_max_blocks * BLOCK_SIZE_IN_BYTES;
 
     block_bytes[message_size] = 1;
-    block_bytes[real_blocks_bytes - 1] = 0x80;
+    //block_bytes[real_blocks_bytes - 1] = 0x80;
+    if message_size == real_blocks_bytes - 1 {
+        // combine both padding bits into a single byte
+        block_bytes[message_size] = 0x81;
+    } else {
+        block_bytes[real_blocks_bytes - 1] = 0x80;
+    }
 
     // populate a vector of 64-bit limbs from our byte array
     let mut sliced_buffer =