How to encrypt/decrypt strings with block ciphers

[tjarvstrand]

Hi,

I can't really seem to figure out how to encrypt and decrypt strings using buddy-core.

(defn test []
  (let [eng   (crypto/block-cipher :twofish :cbc)
        iv16  (nonce/random-nonce 16)
        key32 (nonce/random-nonce 32)
        data  (codecs/str->bytes "00000000000000000000000000000000")]
    (crypto/initialize! eng {:key key32 :iv iv16 :op :encrypt})
    (let [r (crypto/process-bytes! eng data)]
      (crypto/initialize! eng {:key key32 :iv iv16 :op :decrypt})
      (codecs/bytes->str (crypto/process-bytes! eng data)))))

Doesn't actually return the string of zeroes, but some value that looks binary.

What am I doing wrong?

[niwinz]

In the last line, you should replace data with r. In your snippet you are trying decrypt plain data and not the previously encrypted data.

[niwinz]

If you are working with strings, maybe you find that https://github.com/funcool/buddy-sign/blob/master/src/buddy/sign/jwe.clj#L84 useful. Is a collection of helpers for work with arbitrary length strings and encrypt/decrypt them using block ciphers.

In future versions I have plan expose them (or similar) as public api in buddy-core.

[tjarvstrand]

Of course, that was clumsy of me. I had some troubles getting it to work and I was sloppy when trying to write a minimal example. Thanks for the pointers, that helps!