added xorCorrelator-Test

xorCorrelator.py

@@ -0,0 +1,41 @@
+import secrets
+
+def xor(a: bytes, b: bytes):
+    if len(a)!=len(b):
+        raise Exception("Bad Length")
+    return bytes([a[i]^b[i] for i in range(len(a))])
+
+def cbcXor(blocks, key: bytes, iv: bytes = None, BS=16):
+    if len(key)!=BS:
+        raise Exception("Bad key len")
+    if not iv:
+        iv = secrets.token_bytes(16)
+    lastBlock = iv
+    res = []
+    for block in blocks:
+        if len(block)!=BS:
+            raise Exception("Bad block length")
+        mid = xor(block, lastBlock)
+        enc = xor(mid, key)
+        lastBlock = enc
+        res.append(enc)
+    return res
+
+def decCbcXor(blocks, key: bytes, iv: bytes = None, BS=16):
+    if len(key)!=BS:
+        raise Exception("Bad key len")
+    if not iv:
+        iv = secrets.token_bytes(16)
+    lastBlock = iv
+    res = []
+    for block in blocks:
+        if len(block)!=BS:
+            raise Exception("Bad block length")
+        mid = xor(block, key)
+        enc = xor(mid, lastBlock)
+        lastBlock = block
+        res.append(enc)
+    return res
+
+def randBlocks(num: int = 64):
+    return [secrets.token_bytes(16) for i in range(num)]