This commit imports the x/crypto/pbkdf2 package as described in the
linked proposal. The code is unchanged with the exception of a few
small updates to reflect feedback from the proposal comment period:
* the Key function is made generic over a hash.Hash
* the h function is moved to be the first argument
* keyLen is renamed to keyLength
* an error return is added
* the unit tests were moved to the pbkdf2_test package
Updates #69488
Change-Id: If72f854daeb65a5c7fbe45ebd341e63a33340624
Reviewed-on: https://go-review.googlesource.com/c/go/+/628135 Reviewed-by: Dmitri Shuralyov <dmitshur@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com> Reviewed-by: Russ Cox <rsc@golang.org>