Low speed SHA1/2/3 message digest in Bash
This is an implementation of MD5, SHA1 and SHA2 message digest algorithms, using only pure bash without any external programs. No dependencies, other than a recent version of bash.
NEW: SHA3 is also implemented, setting a new slowness record at an exceptional processing rate of almost 20 bytes/second.
WARNING: THIS IS EXTREMELY SLOW AND INEFFICIENT. DO NOT USE IT FOR ANY SERIOUS PURPOSE, AND DO NOT USE IT ON LARGE AMOUNTS OF DATA (EVEN A FEW TENS OF KB ARE ALREADY A LOT FOR THIS BEAST). YOU HAVE BEEN WARNED.
See the following comparison with openssl to calculate the SHA2-512 digest of a ~50K file:
$ ls -l /bin/cmp
-rwxr-xr-x 1 root root 51856 Apr 8 2019 /bin/cmp
$ time openssl sha512 /bin/cmp > /dev/null
real 0m0.016s
user 0m0.007s
sys 0m0.008s
$ time ./sha512.sh < /bin/cmp > /dev/null
real 1m29.471s
user 1m29.397s
sys 0m0.071s
But where we really shine is with SHA3 processing:
$ ls -l /bin/unstr
-rwxr-xr-x 1 root root 14088 Apr 8 2019 /bin/unstr
$ time openssl sha3-256 /bin/unstr > /dev/null
real 0m0.004s
user 0m0.000s
sys 0m0.004s
$ time ./sha3-256.sh < /bin/unstr > /dev/null
real 12m22.685s
user 12m14.812s
sys 0m1.882s
Just run the sha*.sh script that you want/need, feeding input on stdin (so use pipes or redirections). Sample run:
$ echo foobarbazzz12345 | ./sha1.sh
2654fedc3cbf3add0a1a49b8fd8ae735013f4973
$ echo foobarbazzz12345 | ./sha3-512.sh
5c7e1cbb5b9cdae65c0467db7cc3b236cf8c5c47f06ae63d038ca09ec4cd308904887c20f7bb354a58e3c5d0c956c697267ab7137fb9303ee1f73049f58c0c79
shake128.sh and shake256.sh are variable-length output digests, so an optional argument may be specified, indicating the desired output length (in bytes).
If you feel masochistic, there are some test scripts inside the tests/ directory. Just run the one(s) you want from the root of the repo.