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Simple Ruby wrapper for encryption/decryption using OpenSSL
class Crypto
# encrypts data with the given key. returns a binary data with the
# unhashed random iv in the first 16 bytes
def self.encrypt(data, key)
cipher = OpenSSL::Cipher::Cipher.new("aes-256-cbc")
cipher.encrypt
cipher.key = key = Digest::SHA256.digest(key)
random_iv = cipher.random_iv
cipher.iv = Digest::SHA256.digest(random_iv + key)[0..15]
encrypted = cipher.update(data)
encrypted << cipher.final
# add unhashed iv to front of encrypted data
return random_iv + encrypted
end
def self.decrypt(data, key)
cipher = OpenSSL::Cipher::Cipher.new("aes-256-cbc")
cipher.decrypt
cipher.key = cipher_key = Digest::SHA256.digest(key)
random_iv = data[0..15] # extract iv from first 16 bytes
data = data[16..data.size-1]
cipher.iv = Digest::SHA256.digest(random_iv + cipher_key)[0..15]
begin
decrypted = cipher.update(data)
decrypted << cipher.final
rescue OpenSSL::CipherError, TypeError
return nil
end
return decrypted
end
end
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