Hawkynt

LION

Variable block-size cipher construction combining hash function and stream cipher in three-round Feistel structure. Security depends on inner primitives. This implementation uses SHA-1 and RC4.

Properties

Property	Value
Category	Block Ciphers
Sub-category	Block Cipher Construction
Security status	Not classified
Complexity	Advanced
Inventor	Ross Anderson, Eli Biham
Year	1996
Origin	🇬🇧 United Kingdom
Source	algorithms/block/lion.js

Parameters

Parameter	Supported values
Key sizes	2 bytes (16 bits) to 40 bytes (320 bits) in steps of 2 bytes
Block sizes	64 bytes (512 bits)

Security

Status: not classified — treat as unverified.

No vulnerabilities are recorded for this implementation.

Documentation

• Original Paper: Two Practical and Provably Secure Block Ciphers
• Wikipedia - BEAR and LION Ciphers
• Botan Library Implementation

References

• lioness-rs (LIONESS wide-block cipher, Anderson-Biham construction)
• pylioness (LIONESS wide-block cipher, Anderson-Biham construction)

Test vectors

1 vector ship with this algorithm and run in the test suite. Byte values are hexadecimal.

Vector 1 — Botan Test Vector - LION(SHA-1,RC4,64)

Field	Value
key	00112233445566778899aabbccddeeff00112233445566778899aabbccddeeff
input	1112131415161718191a1b1c1d1e1f20 2122232425262728292a2b2c2d2e2f30 31323334353637382015b3db2dc49529 c2d26b1f1e86c65ec7b946ab2d2e2f30
expected	bce3be866ef63af5ad4cba8c3caa2aa9 cf9bb3cc2a3d77ff7c05d0ec7e684ad6 134abfd7df6842b7292071064c9f4dfe 4b9d34eae89201136b7ce70ed4a190db

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