Hawkynt

SHX (Serpent Extended)

Extended Serpent cipher with 256/512/1024-bit keys from CEX library. Educational implementation with increased rounds (40/48/64) for enhanced security margins.

Properties

Property	Value
Category	Block Ciphers
Sub-category	Extended Block Cipher
Security status	🎓 Educational Only
Complexity	Expert
Inventor	John Underhill (CEX)
Year	2018
Origin	🇨🇦 Canada
Source	algorithms/block/shx.js

Parameters

Parameter	Supported values
Key sizes	32 bytes (256 bits); 64 bytes (512 bits); 128 bytes (1024 bits)
Block sizes	16 bytes (128 bits)

Security

Status: 🎓 Educational Only

Known vulnerabilities

Issue	Description	Mitigation
Extended Cipher Analysis	Extended versions of standard ciphers may have different security properties	Use only for educational purposes and research into extended cipher designs

Documentation

• CEX Cryptographic Library
• Original Serpent Specification
• RFC 5869: HKDF Specification

References

• CEX Extended Serpent Reference
• Extended Block Cipher Design Principles
• NIST Post-Quantum Cryptography

Test vectors

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

Vector 1 — SHX 256-bit key test vector

Field	Value
key	0000000000000000000000000000000000000000000000000000000000000000
input	00000000000000000000000000000000
expected	380fb7897f9c7c2d4f88a36df031dc93

Vector 2 — SHX 512-bit key test vector

Field	Value
key	00000000000000000000000000000000 00000000000000000000000000000000 00000000000000000000000000000000 00000000000000000000000000000000
input	01010101010101010101010101010101
expected	d6a065a5a52d5c9d307a5be514c884dc

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