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REDOC II

Michael Wood’s cipher for Cryptech Inc: 80-bit blocks, a 160-bit key and 10 rounds of substitutions, key-table XORs, enclave functions and permutations, each chosen by a block byte XORed with a mask byte. The key expands into a 256-row key table and a 10x10 mask table. Follows Wood’s reference source code.

Properties

Property	Value
Category	Block Ciphers
Sub-category	Block Cipher
Security status	❌ Broken
Complexity	Advanced
Inventor	Michael Wood
Year	1990
Origin	🇺🇸 United States
Source	algorithms/block/redoc.js

Parameters

Parameter	Supported values
Key sizes	20 bytes (160 bits)
Block sizes	10 bytes (80 bits)

Security

Status: ❌ Broken

Known vulnerabilities

Issue	Description	Mitigation
Differential cryptanalysis	Biham and Shamir attack one round with about 2300 encryptions and recover three masks of up to four rounds faster than exhaustive search; Cusick found another one-round attack.	Use AES or another vetted cipher.

Documentation

• Applied Cryptography source code (REDOC2.ZIP by Michael Wood)
• Cusick, Wood - “The REDOC II Cryptosystem”, CRYPTO ‘90
• Wikipedia: REDOC
• US Patent 5,003,596 (Wood)

References

• REDOC II reference source (Michael Wood)

Test vectors

6 vectors ship with this algorithm and run in the test suite. Byte values are hexadecimal.

Vector 1 — REDOC II reference - sample key and block of the reference source (“ABCDEFGHIJ”)

Field	Value
key	724d3e0e5b71e9aa3898ffde1a9bd5f80c6d4e5f
input	4142434445464748494a
expected	d3e1b40d11f4c81224ca

Vector 2 — REDOC II reference - zero key, zero block

Field	Value
key	0000000000000000000000000000000000000000
input	00000000000000000000
expected	f00bb85e8f9205917b57

Vector 3 — REDOC II reference - incrementing key and block

Field	Value
key	000102030405060708090a0b0c0d0e0f10111213
input	00010203040506070809
expected	98b8a06b23bf702b729e

Vector 4 — REDOC II reference - all-ones key and block

Field	Value
key	ffffffffffffffffffffffffffffffffffffffff
input	ffffffffffffffffffff
expected	cba888ddd1b273eb965e

Vector 5 — REDOC II reference - mixed key and block

Field	Value
key	2b7e151628aed2a6abf7158809cf4f3c762e7160
input	6bc1bee22e409f96e93d
expected	0f78543ed2e217aaa2bf

Vector 6 — REDOC II reference - single set bit in the block

Field	Value
key	0123456789abcdeffedcba987654321000112233
input	80000000000000000000
expected	d1d49c32755140ea71ca

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