Commit 91372399 authored by Steven Fackler's avatar Steven Fackler
Browse files

Add convenience functions for AEAD encryption/decryption

parent e230d20f

openssl/src/symm.rs

+57 −14
Original line number Diff line number Diff line
@@ -345,6 +345,48 @@ fn cipher(t: Cipher, 
    Ok(out)

}



/// Like `encrypt`, but for AEAD ciphers such as AES GCM.

///

/// Additional Authenticated Data can be provided in the `aad` field, and the authentication tag

/// will be copied into the `tag` field.

pub fn encrypt_aead(t: Cipher,

                    key: &[u8],

                    iv: Option<&[u8]>,

                    aad: &[u8],

                    data: &[u8],

                    tag: &mut [u8])

                    -> Result<Vec<u8>, ErrorStack> {

    let mut c = try!(Crypter::new(t, Mode::Encrypt, key, iv));

    let mut out = vec![0; data.len() + t.block_size()];

    try!(c.aad_update(aad));

    let count = try!(c.update(data, &mut out));

    let rest = try!(c.finalize(&mut out[count..]));

    try!(c.get_tag(tag));

    out.truncate(count + rest);

    Ok(out)

}



/// Like `decrypt`, but for AEAD ciphers such as AES GCM.

///

/// Additional Authenticated Data can be provided in the `aad` field, and the authentication tag

/// should be provided in the `tag` field.

pub fn decrypt_aead(t: Cipher,

                    key: &[u8],

                    iv: Option<&[u8]>,

                    aad: &[u8],

                    data: &[u8],

                    tag: &[u8])

                    -> Result<Vec<u8>, ErrorStack> {

    let mut c = try!(Crypter::new(t, Mode::Decrypt, key, iv));

    let mut out = vec![0; data.len() + t.block_size()];

    try!(c.aad_update(aad));

    let count = try!(c.update(data, &mut out));

    try!(c.set_tag(tag));

    let rest = try!(c.finalize(&mut out[count..]));

    out.truncate(count + rest);

    Ok(out)

}



#[cfg(ossl110)]

use ffi::{EVP_CIPHER_iv_length, EVP_CIPHER_block_size, EVP_CIPHER_key_length};
@@ -608,22 +650,23 @@ mod tests { 
             f4fc97416ee52abe";

        let tag = "e20b6655";



        let mut crypter = Crypter::new(Cipher::aes_128_gcm(), Mode::Encrypt, &key.from_hex().unwrap(), Some(&iv.from_hex().unwrap())).unwrap();

        let mut out = [0; 1024];

        crypter.aad_update(&aad.from_hex().unwrap()).unwrap();

        let mut nwritten = crypter.update(&pt.from_hex().unwrap(), &mut out).unwrap();

        nwritten += crypter.finalize(&mut out[nwritten..]).unwrap();

        assert_eq!(ct, out[..nwritten].to_hex());

        let mut actual_tag = [0; 4];

        crypter.get_tag(&mut actual_tag).unwrap();

        let out = encrypt_aead(Cipher::aes_128_gcm(),

                               &key.from_hex().unwrap(),

                               Some(&iv.from_hex().unwrap()),

                               &aad.from_hex().unwrap(),

                               &pt.from_hex().unwrap(),

                               &mut actual_tag)

            .unwrap();

        assert_eq!(ct, out.to_hex());

        assert_eq!(tag, actual_tag.to_hex());



        let mut crypter = Crypter::new(Cipher::aes_128_gcm(), Mode::Decrypt, &key.from_hex().unwrap(), Some(&iv.from_hex().unwrap())).unwrap();

        let mut out = [0; 1024];

        crypter.aad_update(&aad.from_hex().unwrap()).unwrap();

        let mut nwritten = crypter.update(&ct.from_hex().unwrap(), &mut out).unwrap();

        crypter.set_tag(&tag.from_hex().unwrap()).unwrap();

        nwritten += crypter.finalize(&mut out[nwritten..]).unwrap();

        assert_eq!(pt, out[..nwritten].to_hex());

        let out = decrypt_aead(Cipher::aes_128_gcm(),

                               &key.from_hex().unwrap(),

                               Some(&iv.from_hex().unwrap()),

                               &aad.from_hex().unwrap(),

                               &ct.from_hex().unwrap(),

                               &tag.from_hex().unwrap()).unwrap();

        assert_eq!(pt, out.to_hex());

    }

}