Known Answer Tests for Multimixer-128: Universal Keyed Hashing, based on Integer Multiplication

git.patch

diff --git a/ReferenceCode/Multimixer-128.py b/ReferenceCode/Multimixer-128.py
index 2f9b11e..54cb0a6 100644
--- a/ReferenceCode/Multimixer-128.py
+++ b/ReferenceCode/Multimixer-128.py
@@ -96,9 +96,70 @@ def Int_multimix(M,K):
 #256 = block size of Multimixer-128
 
 
-l = int(input("Enter message Length:   "))            
+def gen_rand_bytes(l: int) -> bytes:
+    return bytes([random.randint(0x00, 0xff) for i in range(l)])
 
-Msg = rand_key(l*256)
-Key = rand_key(l*256)
+def bytes_to_bitstring(data: bytes, word_size_bits: int = 32) -> str:
+    word_size_bytes = word_size_bits // 8
+    word_cnt = len(data) // word_size_bytes
 
-print(Int_multimix(Msg, Key))
+    assert word_size_bytes in [4, 8], "Word size must be 32, 64 -bits !"
+
+    bs = ''
+    for i in range(word_cnt):
+        block = data[i * word_size_bytes:(i + 1) * word_size_bytes]
+        word = int.from_bytes(block, byteorder='little')
+
+        if word_size_bytes == 4:
+            bits = '{:032b}'.format(word)
+        else:
+            bits = '{:064b}'.format(word)
+
+        bs += bits
+    return bs
+
+def bitstring_to_bytes(bs: str, word_size_bits: int = 64) -> bytes:
+    word_size_bytes = word_size_bits // 8
+    word_cnt = len(bs) // word_size_bits
+
+    data = b''
+    for i in range(word_cnt):
+        bits = bs[i * word_size_bits:(i + 1) * word_size_bits]
+        word = int(bits, base=2)
+        block = word.to_bytes(word_size_bytes, byteorder='little')
+        data += block
+    return data
+
+if __name__ == '__main__':
+    BLOCK_SIZE_BYTES = 32
+    KAT_COUNT = 256
+
+    IN_WORD_SIZE_BITS = 32
+    OUT_WORD_SIZE_BITS = IN_WORD_SIZE_BITS*2
+
+    IN_WORD_SIZE_BYTES = IN_WORD_SIZE_BITS/ 8
+    OUT_WORD_SIZE_BYTES = OUT_WORD_SIZE_BITS/ 8
+
+    SEED = 1
+    random.seed(SEED)
+
+    for i in range(KAT_COUNT):
+        mlen = (i+1) * BLOCK_SIZE_BYTES
+
+        key = gen_rand_bytes(mlen)
+        msg = gen_rand_bytes(mlen)
+
+        key_bits = bytes_to_bitstring(key, word_size_bits=IN_WORD_SIZE_BITS)
+        msg_bits = bytes_to_bitstring(msg, word_size_bits=IN_WORD_SIZE_BITS)
+
+        assert bitstring_to_bytes(key_bits, word_size_bits=IN_WORD_SIZE_BITS) == key
+        assert bitstring_to_bytes(msg_bits, word_size_bits=IN_WORD_SIZE_BITS) == msg
+
+        md_bits = Int_multimix(msg_bits, key_bits)
+        md = bitstring_to_bytes(md_bits, word_size_bits=OUT_WORD_SIZE_BITS)
+        assert bytes_to_bitstring(md, word_size_bits=OUT_WORD_SIZE_BITS) == md_bits
+
+        print(f"mlen = {mlen}")
+        print(f"key = {key.hex()}")
+        print(f"msg = {msg.hex()}")
+        print(f"md = {md.hex()}\n")

Steps for Reproducibly Generating KAT Files for Multimixer-128

Multimixer-128 is a universal keyed hashing scheme, based on 32 -bit integer addition and multiplication, which was defined in paper https://eprint.iacr.org/2023/1357.pdf. I implemented Multimixer-128 as a Rust library in https://github.com/itzmeanjan/multimixer-128. But I couldn't find any KAT files, to ensure functional correctness and conformance of my library implementation, so I took the venture of creating a few, using the reference implementation of Multimixer-128, that was supplied by authors.

1. Clone git repository, holding reference implementation of Multimixer-128.

git clone https://github.com/Parisaa/Multimixer.git
pushd Multimixer/
git checkout 797bbba9d2b3c3ec15403cbf3d7ef588ec16d81d # Important step
popd

2. Clone git repository, holding above git patch.

git clone https://gist.github.com/a32eab0244af55eba2847c6472337535.git
pushd a32eab0244af55eba2847c6472337535
sha256sum git.patch # Must be 5b23db7ea62dc1a6c38c7cb67c92b65f5e74b1e491b45bfd1ecb12d30f9ffbf8
popd

3. Apply git patch on reference implementation of Multimixer-128.

cp a32eab0244af55eba2847c6472337535/git.patch Multimixer/
pushd Multimixer/
git apply git.patch
git diff # Optional, but shows the changes applied
popd

4. Generate Known Answer Tests.

pushd Multimixer/
python3 ReferenceCode/Multimixer-128.py | tee multimixer128.kat
sha256sum multimixer128.kat # Must be 88bb132696e986dd859af44a0d343d0e62a8e70feb0c159d6b69aee5dfe83094
popd

Generated KAT file (multimixer128.kat) lives in the root directory of the reference implementation.