waldner / bachacha

ChaCha20 in bash

baCHACHA

Hot, low speed CHACHA20 encryption in Bash

What's this?

This is an implementation of ChaCha20 (also) encryption without any external programs. No dependencies, other than a recent version of bash.

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.

Why is it "low speed"?

See the following comparison with openssl to encrypt a file:

$ ls -al /bin/w
-rwxr-xr-x 1 root root 22576 Feb 13 20:05 /bin/w
$ time openssl chacha20 -K 9900000000000000000000000000000000000000000000000000000000000001 -iv 00000000000000002607000a00040001 < /bin/w > /dev/null

real	0m0.005s
user	0m0.005s
sys	0m0.000s
$ time ./chacha.sh -K 9900000000000000000000000000000000000000000000000000000000000001 -I 2607000a00040001 < /bin/w > /dev/null

real	0m7.388s
user	0m7.099s
sys	0m0.140s

How do I install it?

Just run the chacha.sh script with the necessary arguments (see chacha.sh -h for help).

How do I know that it produces correct results?

There are two test scripts in the tests/ directory, whose job is to compare results from chacha.sh and openssl chacha20 (see comments in the scripts). All tests should pass.