Table of Contents

LSH (KS X 3262) Test Vectors

Overview

LSH is the Korean national cryptographic hash standard defined in KS X 3262, designed by KISA (Korea Internet & Security Agency). It comes in two families: LSH-256 (32-bit words) and LSH-512 (64-bit words), each supporting multiple output sizes.

Specification

  • Standard: KS X 3262 (South Korea), approved by KCMVP
  • Families: LSH-256 (32-bit words) and LSH-512 (64-bit words)
  • Output Sizes:
    • LSH-256: 224 or 256 bits
    • LSH-512: 224, 256, 384, or 512 bits
  • Block Size: 128 bytes (LSH-256) or 256 bytes (LSH-512)
  • Steps: 26 (LSH-256) or 28 (LSH-512)
  • Structure: Wide-pipe Merkle-Damgård with 16-word chaining variable split into left/right halves

Official Reference

Test Vectors

Test vectors sourced from the Wikipedia LSH hash function article.

LSH-256

Vector 1: "abc" — LSH-256-224

Input:  "abc" (ASCII)
Length: 3 bytes

Output (LSH-256-224):
F7C53BA4034E708E74FBA42E55997CA5126BB7623688F85342F73732

Vector 2: "abc" — LSH-256-256

Input:  "abc" (ASCII)
Length: 3 bytes

Output (LSH-256-256):
5FBF365DAEA5446A7053C52B57404D77A07A5F48A1F7C1963A0898BA1B714741

LSH-512

Vector 1: "abc" — LSH-512-224

Input:  "abc" (ASCII)
Length: 3 bytes

Output (LSH-512-224):
D1683234513EC5698394571EAD128A8CD5373E97661BA20DCF89E489

Vector 2: "abc" — LSH-512-256

Input:  "abc" (ASCII)
Length: 3 bytes

Output (LSH-512-256):
CD892310532602332B613F1EC11A6962FCA61EA09ECFFCD4BCF75858D802EDEC

Vector 3: "abc" — LSH-512-384

Input:  "abc" (ASCII)
Length: 3 bytes

Output (LSH-512-384):
5F344EFAA0E43CCD2E5E194D6039794B4FB431F10FB4B65FD45E9DA4ECDE0F27
B66E8DBDFA47252E0D0B741BFD91F9FE

Vector 4: "abc" — LSH-512-512

Input:  "abc" (ASCII)
Length: 3 bytes

Output (LSH-512-512):
A3D93CFE60DC1AACDD3BD4BEF0A6985381A396C7D49D9FD177795697C3535208
B5C57224BEF21084D42083E95A4BD8EB33E869812B65031C428819A1E7CE596D

Algorithm Details

Chaining Variable

Both families use a 16-word chaining variable (CV) split into left and right halves of 8 words:

LSH-256: CV = 16 × 32-bit words = 512 bits (wide-pipe for ≤256-bit output)
LSH-512: CV = 16 × 64-bit words = 1024 bits (wide-pipe for ≤512-bit output)

Step Function

Each step applies three operations in sequence:

  1. Message Addition — XOR sub-message words into the chaining variable
  2. Mixing Function — Rotation-based diffusion with alternating constants:
    • LSH-256: α=29, β=1 (even steps); α=5, β=17 (odd steps); γ = [0, 8, 16, 24, 24, 16, 8, 0]
    • LSH-512: α=23, β=59 (even steps); α=7, β=3 (odd steps); γ = [0, 16, 32, 48, 8, 24, 40, 56]
  3. Word Permutation — Fixed permutation τ applied to the chaining variable words

Finalization

After all steps:

H[l] = cv_L[l] ⊕ cv_R[l]    (for l = 0..7)

The hash is taken from the first hashSize bytes of H.

Padding

LSH uses standard one-zeros padding: append 0x80, then zero bytes to fill the block.

Compliance Requirements

LSH is required for:

  • Korean government cryptographic applications
  • Products certified under KCMVP (Korea Cryptographic Module Validation Program)
  • Systems requiring compliance with KS X 3262
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