RIPEMD256 hash

 

About RIPEMD256 hash

RIPEMD-256 (RACE Integrity Primitives Evaluation Message Digest) is a cryptographic hash function designed as an extension and improvement over RIPEMD-128 and RIPEMD-160. It produces a 256-bit hash value, offering stronger security and higher collision resistance compared to its predecessors.

Characteristics of RIPEMD-256

  1. Fixed-Length Output:

    • RIPEMD-256 produces a fixed-length output of 256 bits (32 bytes), regardless of the input data's length.

  2. Input Padding:

    • RIPEMD-256 pads the input message so that its length is congruent to 448 modulo 512 bits. Padding involves appending a single '1' bit followed by '0' bits until the message length is 64 bits short of a multiple of 512. The length of the original message (before padding) is then appended as a 64-bit integer.

  3. Processing in Blocks:

    • RIPEMD-256 processes the input message in 512-bit (64-byte) blocks.

  4. Initialization Vector (IV):

    • RIPEMD-256 uses an initial vector (IV) consisting of eight 32-bit words:
      • IV0 = 0x67452301
      • IV1 = 0xEFCDAB89
      • IV2 = 0x98BADCFE
      • IV3 = 0x10325476
      • IV4 = 0xC3D2E1F0
      • IV5 = 0x76543210
      • IV6 = 0xFEDCBA98
      • IV7 = 0x89ABCDEF

  5. Compression Function:

    • The compression function of RIPEMD-256 involves multiple rounds of operations, including bitwise logical functions (AND, OR, XOR, NOT), additions modulo 2^32, rotations, and bitwise shifts.

Algorithm Steps

  1. Initialization:

    • Initialize the state variables (A, B, C, D, E, F, G, H) to the IV values.

  2. Padding:

    • Pad the input message according to the specified padding rules.

  3. Processing:

    • Divide the padded message into 512-bit blocks.
    • For each block, perform the rounds of the compression function, updating the state variables.

  4. Output:

    • After processing all blocks, concatenate the state variables (A, B, C, D, E, F, G, H) to produce the final 256-bit hash value.

Security and Usage

  • Security:

    • RIPEMD-256 is designed to provide strong security against collision attacks and preimage attacks. Its 256-bit output size makes it suitable for applications requiring higher security guarantees compared to its shorter variants like RIPEMD-128 and RIPEMD-160.

  • Usage:

    • RIPEMD-256 has been used in various cryptographic applications such as digital signatures, message authentication codes (MACs), and data integrity verification. However, its usage has been less prevalent compared to SHA-2 and SHA-3, which offer stronger security assurances and are more widely adopted in modern cryptographic protocols.

Summary

RIPEMD-256 is a cryptographic hash function that produces a 256-bit hash value. It provides strong security properties against collision attacks and preimage attacks, making it suitable for applications requiring higher security guarantees than its shorter predecessors. While historically significant, its adoption has been overshadowed by more widely accepted hash functions like SHA-2 and SHA-3 in contemporary cryptographic applications.