Extendableoutput
Extendableoutput refers to the cryptographic concept of an extendable-output function, or XOF, a function whose output length can be chosen by the caller. An XOF takes a message and produces a stream of bytes of arbitrary length, while maintaining security properties similar to fixed-length hash functions over the portion of output that is requested.
XOFs are typically built from sponge constructions, such as the Keccak family. In a sponge-based XOF, input
Common examples include SHAKE-128 and SHAKE-256, which are part of the SHA-3 family, as well as variants
Security and usage considerations include relying on well-vetted sponge constructions, applying proper domain separation, and ensuring