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SHAKE & cSHAKE

links: AC1 TOC - Private Key Encryption - Index


SHAKE

  • SHAKE (Secure Hash Algorithm and KECCAK) is an Extendable-Output Function (or XOF)
  • It is like SHA-3 but with an infinite output
  • can be used as a KDF, a PRNG, a Stream Cipher, ...
  • based on the Keccak permutation function

cSHAKE

  • cSHAKE is a customisable version of SHAKE
  • has one new input: a customization string
  • the purpose is to avoid collisions between different usages of the SHAKE function

Examples

  • In KMAC, the cSHAKE function is called with the customization string "KMAC"
  • two examples given by the NIST publication:
    • cSHAKE128(public_key, 256, "", "key fingerprint")
    • cSHAKE128(email_contents, 256, "", "email signature")

Source: Link


links: AC1 TOC - Private Key Encryption - Index