Take the 2-minute tour ×
Cryptography Stack Exchange is a question and answer site for software developers, mathematicians and others interested in cryptography. It's 100% free, no registration required.

Historically hashes have been from a large set (say 256 characters) to a smaller set (256 bits).

Also, hash functions that are P-complete have no known parallel algorithm; they must be computed serially which ensures a certain amount of temporal cost in computing them.

Three questions:

1)What is the technical term for hashes that map to a larger set than the domain?

2)Are there any good P-complete hashes?

3)Are there any good P-complete hashes that map to a larger set?

share|improve this question

migrated from security.stackexchange.com Dec 19 '12 at 18:00

This question came from our site for Information security professionals.

Encoding the string into a Game of Life grid and playing K rounds is an example of a P-complete hash. There must be a better one out there. –  Chad Brewbaker Dec 19 '12 at 17:43
Combining a hash with an iterated stream cipher should do the trick. –  CodesInChaos Dec 23 '12 at 23:10

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.

Browse other questions tagged or ask your own question.