### What is SHA384?

SHA384 is a cryptographic hash function in the
SHA2
family. It takes an arbitrary amount of data and maps it to a fixed number of bits,
in this case 384. While it hasn’t been proven, it’s believed to uninvertable,
that is, it’s impossible to get back to the original data from its hash.

The SHA2 Family contains two interesting functions, SHA-256 and SHA-512,
which are 32 bit and 64 bit version of essentially the same function, while
**SHA-384** is a truncated version of SHA512 computed with a
different initial value.

### Why use SHA384?

Since SHA384 is a truncated version of SHA512, why would you prefer it over
SHA512, after all more bits is better right? Well, one you’ve hit 256
bits, you’re already dealing with a phenomenally large output space, so
it’s mostly a matter of how many output bits you need.

See
this stackoverflow post
for more information. Additionally SHA384 isn’t vulnerable to
length extension attacks
while SHA256 and SHA512 are.