This CL adds the package argon2. The argon2 package implements
the Argon2 PBKDF family (Argon2i, Argon2d, Argon2id).
Argon2 is memory-hard key derivation function and is specified
at https://github.com/P-H-C/phc-winner-argon2/blob/master/argon2-specs.pdf
It can be used to derive cryptographic keys with high entropy from low
entropy passwords.
Fixesgolang/go#19896
Change-Id: I5b099682a8e3d7569ad18400cebddefc99a7e22f
Reviewed-on: https://go-review.googlesource.com/82575
Run-TryBot: Adam Langley <agl@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Adam Langley <agl@golang.org>