The bcrypt implementation must append a zero byte to the user provided key to be compatible to C implementations. This will change the user provided key if the slice has enough capacity to hold the extra zero byte. This change always allocates a new slice for the C-compatible key. Fixes golang/go#20425 Change-Id: I8dc4e840c29711daabdabe58d83643cc0103cedd Reviewed-on: https://go-review.googlesource.com/43715 Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org> TryBot-Result: Gobot Gobot <gobot@golang.org> Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>