[openssl-dev] Variable length of digest

[Viktor Dukhovni]

On Wed, Dec 23, 2015 at 10:18:55PM +0000, Dr. Stephen Henson wrote:

> That's an interesting question. What digest requires this? Is the output
> length arbitrary or do the standards specify a maximum size?

With SHA3, NIST differentiates between fixed-length hash functions
and variable-length XOFs.

Introduction of variable length digests into OpenSSL would break
applications that expect the EVP_MD family of functions to produce
fixed length (input data indepdendent) results.

If there's a new construct whose output size depends on the input
data, that probably requires a new family of functions.

-- 
	Viktor.