Understanding cSHAKE128: Customizable SHAKE128

cSHAKE128 is a customizable variant of the SHAKE128 extendable-output function (XOF) from the SHA-3 family. It allows for additional customization through function name and customization string parameters, making it suitable for domain separation and specific use cases.

Key Features of cSHAKE128

• Customizable output length (128 bits minimum)
• Function name parameter for domain separation
• Customization string for additional flexibility
• Part of the SHA-3 family of hash functions
• Secure and well-tested cryptographic primitive

Checksum Applications

While cSHAKE128 and cSHAKE256 can be used for checksums, they are typically considered overkill for simple data verification tasks. Their true value lies in specialized applications where:

• Domain separation is required between different checksum applications
• Customizable output lengths are needed for specific protocols
• Additional security features beyond basic checksums are necessary
• Integration with other cryptographic protocols is required

For standard checksum applications, simpler algorithms like CRC32 or MD5 are often more practical and efficient.

Common Uses

• Cryptographic key derivation
• Message authentication codes (MACs)
• Digital signatures
• Random number generation
• Domain separation in cryptographic protocols

Security Considerations

• Provides 128 bits of security against collision attacks
• Resistant to length extension attacks
• Customization parameters help prevent cross-protocol attacks
• Based on the Keccak sponge construction