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

You mean this one?: ActiveSupport::MessageEncryptor. Here is the way to reuse Rails 4 application's secret:

crypt = ActiveSupport::MessageEncryptor.new(Rails.application.secrets.secret_key_base)
encrypted_data = crypt.encrypt_and_sign('my confidental data')

And encrypted data can be decrypted with:

decrypted_back = crypt.decrypt_and_verify(encrypted_data)

Previously Rails 3 was using secret_token configuration option and encryptor methods were encrypt decrypt.

Answer 2

Rails 5 update:

crypt = ActiveSupport::MessageEncryptor.new(Rails.application.secrets.secret_key_base[0..31])
encrypted_data = crypt.encrypt_and_sign('my confidental data')

Rails 5.x Needs a key of exactly 32 bytes.

To verify a previously signed message with a longer key:

crypt = ActiveSupport::MessageEncryptor.new(Rails.application.secrets.secret_key_base[0..31], Rails.application.secrets.secret_key_base)
encrypted_data = crypt.encrypt_and_sign('my confidental data')

as described in the docu

and the discussion on this change

Answer 3

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)