OpenSSL Errors with AES-256-GCM

parser.ex

defmodule Parser do
  @key "go generate a 32 byte random key"
  @algorithm :aes_gcm
  @auth_data ""

  # Strings generated by this fuction fail to be decrypted unless one of the hardcoded IV values is used.
  def encrypt(bin_data) when is_binary(bin_data) do
    # These two hardcoded values where generated by: OpenSSL::Random.random_bytes(12)
    # iv                        = <<133, 29, 202, 53, 242, 73, 247, 202, 244, 58, 243, 238>>
    # iv                        = <<134, 240, 63, 15, 40, 68, 240, 242, 108, 27, 226, 144>>
    # iv                        = :crypto.rand_bytes(12)
    iv                        = :crypto.strong_rand_bytes(12)
    {cipher_text, cipher_tag} = :crypto.block_encrypt(@algorithm, @key, iv, {@auth_data, bin_data})
    iv <> cipher_tag <> cipher_text
  end

  # This function will return an error if the :crypto.strong_rand_bytes was used to generate the IV.
  def decrypt(<<iv::binary-size(12),cipher_tag::binary-size(16),cipher_text::binary>>) do
    :crypto.block_decrypt(@algorithm, @key, iv, {@auth_data, cipher_text, cipher_tag})
  end
end

Parser.decrypt Parser.encrypt("Hello, world!")

parser.rb

require 'openssl'
class Parser
  def initialize
    @key       = 'go generate a 32 byte random key'
    @algorithm = 'aes-256-gcm'
    @auth_data = ''
  end

  def decrypt(bin_data)
    decipher           = OpenSSL::Cipher.new(@algorithm).decrypt
    decipher.key       = @key
    decipher.iv        = bin_data[0..11]
    decipher.auth_tag  = bin_data[12..27]
    decipher.auth_data = @auth_data

    decipher.update(bin_data[28..-1]) + decipher.final
  end

  def encrypt(bin_data)
    cipher           = OpenSSL::Cipher.new(@algorithm).encrypt
    cipher.key       = @key
    iv               = cipher.random_iv # Calls OpenSSL::Random.random_bytes(12) to set IV internally
    cipher.auth_data = @auth_data
    cipher_text      = cipher.update(bin_data) + cipher.final

    [iv, cipher.auth_tag, cipher_text].join
  end
end

Parser.new.decrypt Parser.new.encrypt("Hello, world!")