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Contents
# frozen_string_literal: true
module Prefab
class Encryption
CIPHER_TYPE = "aes-256-gcm" # 32/12
SEPARATOR = "--"
# Hexadecimal format ensures that generated keys are representable with
# plain text
#
# To convert back to the original string with the desired length:
# [ value ].pack("H*")
def self.generate_new_hex_key
generate_random_key.unpack("H*")[0]
end
def initialize(key_string_hex)
@key = [key_string_hex].pack("H*")
end
def encrypt(clear_text)
cipher = OpenSSL::Cipher.new(CIPHER_TYPE)
cipher.encrypt
iv = cipher.random_iv
# load them into the cipher
cipher.key = @key
cipher.iv = iv
cipher.auth_data = ""
# encrypt the message
encrypted = cipher.update(clear_text)
encrypted << cipher.final
tag = cipher.auth_tag
# pack and join
[encrypted, iv, tag].map { |p| p.unpack("H*")[0] }.join(SEPARATOR)
end
def decrypt(encrypted_string)
unpacked_parts = encrypted_string.split(SEPARATOR).map { |p| [p].pack("H*") }
cipher = OpenSSL::Cipher.new(CIPHER_TYPE)
cipher.decrypt
cipher.key = @key
cipher.iv = unpacked_parts[1]
cipher.auth_tag = unpacked_parts[2]
# and decrypt it
decrypted = cipher.update(unpacked_parts[0])
decrypted << cipher.final
decrypted
end
private
def self.generate_random_key
SecureRandom.random_bytes(key_length)
end
def self.key_length
OpenSSL::Cipher.new(CIPHER_TYPE).key_len
end
end
end
Version data entries
28 entries across 28 versions & 1 rubygems