(XO)Esch, an (Extendable Output) Hash Function

Esch is a family of hash functions. Esch256 outputs digests of 256 bits, and Esch384 of 384 bits. They rely on the sponge construction, like the current hash standard SHA-3.

XOEsch is a family of Extendable Output Functions (XOF) based on Esch. A XOF is essentially a hash function for which the output size can be arbitrarily large.

Esch and XOEsch share the same high-level structure and differ only in the output size and domain separation constants. This structure is depicted in the following figures.

On the Names

Esch is the name of a city in Luxembourg that is very close to the campus of the university of Luxembourg, and lies on the Alzette river.