Either ECB mode is broken in Ruby OpenSSL or I'm retarded...

ecb_test.rb

#!/usr/bin/env ruby

require 'openssl'

# AES-128 ECB mode test vectors
# Taken from: http://www.inconteam.com/software-development/41-encryption/55-aes-test-vectors#aes-ecb-128
KEY        = ["2b7e151628aed2a6abf7158809cf4f3c"].pack("H*")
PLAINTEXT  = ["6bc1bee22e409f96e93d7e117393172a"].pack("H*")
CIPHERTEXT = ["3ad77bb40d7a3660a89ecaf32466ef97"].pack("H*")

cipher = OpenSSL::Cipher::Cipher.new("aes-128-ecb")
cipher.key = KEY
cipher.padding = 0 # Padding is enabled by default o_O

print "Testing encryption: "

cipher.encrypt
ciphertext = cipher.update(PLAINTEXT) << cipher.final

if ciphertext == CIPHERTEXT
  puts "OK!"
else
  puts "FAILED! Got #{ciphertext.inspect} instead of #{CIPHERTEXT.inspect}"
end

print "Testing decryption: "

cipher.reset
cipher.decrypt
plaintext = cipher.update(CIPHERTEXT) << cipher.final

if plaintext == PLAINTEXT
  puts "OK!"
else
  puts "FAILED! Got #{plaintexttext.inspect} instead of #{PLAINTEXT.inspect}"
end

gistfile1.txt

$ ruby --version; ruby ecb_test.rb
ruby 1.9.3p392 (2013-02-22 revision 39386) [x86_64-darwin12.3.0]
Testing encryption: FAILED! Got "\xCE\x9Dp\xDFL\xD0\x95\xC3\x13\x18+\xAC\x1D2\xE7\x15" instead of ":\xD7{\xB4\rz6`\xA8\x9E\xCA\xF3$f\xEF\x97"
Testing decryption: OK!

$ ruby --version; ruby ecb_test.rb
ruby 2.0.0p0 (2013-02-24 revision 39474) [x86_64-darwin12.3.0]
Testing encryption: FAILED! Got "\xCE\x9Dp\xDFL\xD0\x95\xC3\x13\x18+\xAC\x1D2\xE7\x15" instead of ":\xD7{\xB4\rz6`\xA8\x9E\xCA\xF3$f\xEF\x97"
Testing decryption: OK!

$ ruby --version; ruby ecb_test.rb
jruby 1.7.2 (1.9.3p327) 2013-01-04 302c706 on Java HotSpot(TM) 64-Bit Server VM 1.7.0_21-b12 [darwin-x86_64]
Testing encryption: OK!
Testing decryption: OK!

Ever find a solution to this one? It definitely looks like ECB mode is broken based on your tests. I filed a ticket on the ruby project's bug tracker if you want to follow whether it gets fixed. :-)

https://bugs.ruby-lang.org/issues/8720

@netjunki I finally filed a bug for this issue: ruby/openssl#73