DrMoron... The Cipher!
From
Chris M. Thomasson@chris.m.thomasson.1@gmail.com to
sci.crypt on Tue Feb 10 05:07:19 2026
From Newsgroup: sci.crypt
"""
DrMoron: A quirky HMAC-based stream cipher primitive
Core idea: Use HMAC as keystream generator with self-synchronizing feedback,
prepend large TRNG prefix (> digest size), full reverse
between two passes.
Rules (enforced by design intent, not code):
- rand_n MUST be > digest size of chosen hash (e.g. >64 for SHA-512) for strong initial entropy flood.
- Use only secure hashes (SHA-512, SHA3-512, BLAKE2b, BLAKE3 recommended).
- Key: 64-byte TRNG minimum.
- No built-in auth/MAC rCo malleable by design (ciphertext tamper raA atomic garbage output).
- Security claim: Hardness roughly equivalent to breaking HMAC-H under continuous feedback + reverse mixing.
This is raw ciphertext only rCo no bolted-on integrity. Test diffusion, differentials, stats directly.
"""
import hashlib
import hmac
import os
# 1. Improved Hex Utility
# ____________________________________________________________
def ct_bytes_to_hex(data):
"""Returns a clean hex string with 16-byte rows."""
return '\n'.join(data[i:i+16].hex(' ') for i in range(0, len(data), 16)).upper()
# 2. Key Class (Handles Raw Bytes)
# ____________________________________________________________
class ct_secret_key:
def __init__(self, hmac_key, hash_algo, rand_n):
self.hmac_key = hmac_key if isinstance(hmac_key, bytes) else hmac_key.encode()
self.hash_algo = hash_algo
self.rand_n = rand_n
def __repr__(self):
return (f"hmac_key: {self.hmac_key.hex()[:16]}...\n"
f"hash_algo: {self.hash_algo().name}\n"
f"rand_n: {self.rand_n}")
# 3. The Crypt Round Function (Raw Byte Logic)
# ____________________________________________________________
def ct_crypt_round(SK, data_in, decrypt_mode):
"""Single HMAC-feedback round."""
H = hmac.new(SK.hmac_key, None, SK.hash_algo)
H.update(SK.hmac_key[::-1]) # Reversed key for init twist
output = bytearray()
p_idx = 0
p_len = len(data_in)
while p_idx < p_len:
D = H.digest() # Keystream block
d_idx = 0
d_len = len(D)
while p_idx < p_len and d_idx < d_len:
p_byte = data_in[p_idx]
c_byte = p_byte ^ D[d_idx]
output.append(c_byte)
# Feedback: (P,C) encrypt, (C,P) decrypt
if not decrypt_mode:
H.update(bytes([p_byte, c_byte]))
else:
H.update(bytes([c_byte, p_byte]))
p_idx += 1
d_idx += 1
return bytes(output)
# 4. The Main Crypt Wrapper
# ____________________________________________________________
def ct_crypt(SK, data_in, decrypt_mode):
"""Full duplex: forward raA reverse raA forward, with TRNG prefix on encrypt."""
processed_data = data_in
if not decrypt_mode:
# Prepend fresh TRNG prefix (critical for uniqueness)
prefix = os.urandom(SK.rand_n)
processed_data = prefix + processed_data
# Round 1 forward
C = ct_crypt_round(SK, processed_data, decrypt_mode)
# Full reverse (bidirectional diffusion)
C_rev = C[::-1]
# Round 2 forward
final = ct_crypt_round(SK, C_rev, decrypt_mode)
if decrypt_mode:
final = final[SK.rand_n:] # Strip prefix
return final
# ____________________________________________________________
# Simple Test Execution
# ____________________________________________________________
if __name__ == "__main__":
# 64-byte random key (TRNG)
trng_64_bytes = os.urandom(64)
SK = ct_secret_key(
trng_64_bytes,
hashlib.sha512, # Secure default (can swap to sha3_512,
blake2b, etc.)
73 # >64-byte digest, as per rules
)
plaintext = b"ABCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCDE"
# Encrypt
ciphertext = ct_crypt(SK, plaintext, False)
print(f"Ciphertext Hex:\n{ct_bytes_to_hex(ciphertext)}")
# Decrypt & verify
decrypted = ct_crypt(SK, ciphertext, True)
print(f"\nDecrypted String: {decrypted.decode()}")
assert decrypted == plaintext, "Decryption failed!"
print("Round-trip successful.")
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