Encrypt, decrypt using Rails

Question

I saw a while ago the possibility to decrypt and encrypt strings in rails without including any library, but I can\'t find the blog post.

I want to be able to encrypt an

Answer 1

Rails 5 requires that the key be 32 bytes.

Edit to Rails 4 answer that works for Rails 5:

 key = SecureRandom.random_bytes(32)
 crypt = ActiveSupport::MessageEncryptor.new(key) 
 encrypted_data = crypt.encrypt_and_sign('my confidental data')

Decrypt:

 decrypted_back = crypt.decrypt_and_verify(encrypted_data)