This implements SHA-512/256, which generates a 256 bit hash by
calculating the SHA-512 then truncating the result. A different initial
value is used, making the result different from the first 256 bits of
the SHA-512 of the same input. SHA-512 is ~50% faster than SHA-256 on
64bit platforms, so the result is a faster 256 bit hash.
The main goal of this implementation is to enable support for this
faster hashing algorithm in ZFS. The feature was introduced into ZFS
in r289422, but is disconnected because SHA-512/256 support was missing.
A further commit will enable it in ZFS.
This is the follow on to r292782
Reviewed by: cem
Sponsored by: ScaleEngine Inc.
Differential Revision: https://reviews.freebsd.org/D6061
cperciva's libmd implementation is 5-30% faster
The same was done for SHA256 previously in r263218
cperciva's implementation was lacking SHA-384 which I implemented, validated against OpenSSL and the NIST documentation
Extend sbin/md5 to create sha384(1)
Chase dependancies on sys/crypto/sha2/sha2.{c,h} and replace them with sha512{c.c,.h}
Reviewed by: cperciva, des, delphij
Approved by: secteam, bapt (mentor)
MFC after: 2 weeks
Sponsored by: ScaleEngine Inc.
Differential Revision: https://reviews.freebsd.org/D3929
Note that the -c argument's parameter is compared against the digest of
the file, not the file. [1]
Update the "current time" parentheticals for notes about reversing
and colliding the hash functions. [1]
Some general mdoc updates.
PR: docs/188043 [1]
Submitted by: Jamie Landeg-Jones [1]
Approved by: hrs (mentor)
MFC after: 1 week
recent demonstration of a forged SSL certificate. Add text pointing out
that SHA-1 is at least theoretically broken. Add a recommendation that
new applications use SHA-256.
MFC after: 1 month
Avoid using parenthesis enclosure macros (.Pq and .Po/.Pc) with plain text.
Not only this slows down the mdoc(7) processing significantly, but it also
has an undesired (in this case) effect of disabling hyphenation within the
entire enclosed block.
