Running the following code in MRI 1.9.3 and REE 1.8.7 returns true, while running in JRuby (1.6.7.2, 1.7.3, and 1.7.6, in both 1.8 and 1.9 modes) returns false

require 'rubygems'
require 'bcrypt'
require 'base64'
b64h = "BqvyJXQvnL3CKVd6pAv25giyYNEGXg4k5UOwkTeYXZo=\n"
password = "$2a$12$BaVII7NCCtTxF4BKdjPy2.IkvEG4X4/CRhDvmenQKm2r/6pIoW..q"
BCrypt::Password.new(password) == Base64.decode64(b64h)

I've run all the testcases from http://www.mindrot.org/projects/jBCrypt/ and they produce the same results on MRI and JRuby, so this isn't an across-the-board incompatibility, but something about password makes it unhappy. I haven't yet run this in other Bcrypt impls in other languages to see what they return.