How to encrypt data in a UTF-8 string using OpenSSL::Cipher?

Question

In a Rails 3.0 (Ruby 1.9.2) app I'm trying to encrypt some data using something like this:

cipher = OpenSSL::Cipher.new 'aes-256-cbc' cipher.encrypt cipher.key = cipher.random_key cipher.iv = cipher.random_iv  encrypted = cipher.update 'most secret data in the world' encrypted << cipher.final 

That will go into a UTF-8 database. My problem is that

> encrypted.encoding  => #<Encoding:ASCII-8BIT>  > encrypted.encode 'utf-8' Encoding::UndefinedConversionError: "\xF7" from ASCII-8BIT to UTF-8 

How can I get an UTF-8 encrypted string?

Answer 1

The solution is to convert the ASCII-8BIT string to Base64 and then encode to UTF-8.

cipher = OpenSSL::Cipher.new 'aes-256-cbc' cipher.encrypt cipher.key = cipher.random_key cipher.iv = cipher.random_iv  encrypted = cipher.update 'most secret data in the world' encrypted << cipher.final  encoded = Base64.encode64(encrypted).encode('utf-8') 

Once persisted and retrieved from the database,

decoded = Base64.decode64 encoded.encode('ascii-8bit') 

and finally decrypt it.

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PS: If you're curious:

cipher = OpenSSL::Cipher.new 'aes-256-cbc' cipher.decrypt cipher.key = random_key cipher.iv = random_iv  decrypted = cipher.update encoded decrypted << cipher.final  > decrypted  => 'most secret data in the world'