signal-desktop/libtextsecure/test/crypto_test.js

describe('encrypting and decrypting profile data', function() {
  var NAME_PADDED_LENGTH = 26;
  describe('encrypting and decrypting profile names', function() {
    it('pads, encrypts, decrypts, and unpads a short string', function() {
      var name = 'Alice';
      var buffer = dcodeIO.ByteBuffer.wrap(name).toArrayBuffer();
      var key = libsignal.crypto.getRandomBytes(32);

      return textsecure.crypto
        .encryptProfileName(buffer, key)
        .then(function(encrypted) {
          assert(encrypted.byteLength === NAME_PADDED_LENGTH + 16 + 12);
          return textsecure.crypto
            .decryptProfileName(encrypted, key)
            .then(function(decrypted) {
              assert.strictEqual(
                dcodeIO.ByteBuffer.wrap(decrypted).toString('utf8'),
                'Alice'
              );
            });
        });
    });
    it('works for empty string', function() {
      var name = dcodeIO.ByteBuffer.wrap('').toArrayBuffer();
      var key = libsignal.crypto.getRandomBytes(32);

      return textsecure.crypto
        .encryptProfileName(name.buffer, key)
        .then(function(encrypted) {
          assert(encrypted.byteLength === NAME_PADDED_LENGTH + 16 + 12);
          return textsecure.crypto
            .decryptProfileName(encrypted, key)
            .then(function(decrypted) {
              assert.strictEqual(decrypted.byteLength, 0);
              assert.strictEqual(
                dcodeIO.ByteBuffer.wrap(decrypted).toString('utf8'),
                ''
              );
            });
        });
    });
  });
  describe('encrypting and decrypting profile avatars', function() {
    it('encrypts and decrypts', function() {
      var buffer = dcodeIO.ByteBuffer.wrap('This is an avatar').toArrayBuffer();
      var key = libsignal.crypto.getRandomBytes(32);

      return textsecure.crypto
        .encryptProfile(buffer, key)
        .then(function(encrypted) {
          assert(encrypted.byteLength === buffer.byteLength + 16 + 12);
          return textsecure.crypto
            .decryptProfile(encrypted, key)
            .then(function(decrypted) {
              assertEqualArrayBuffers(buffer, decrypted);
            });
        });
    });
    it('throws when decrypting with the wrong key', function() {
      var buffer = dcodeIO.ByteBuffer.wrap('This is an avatar').toArrayBuffer();
      var key = libsignal.crypto.getRandomBytes(32);
      var bad_key = libsignal.crypto.getRandomBytes(32);

      return textsecure.crypto
        .encryptProfile(buffer, key)
        .then(function(encrypted) {
          assert(encrypted.byteLength === buffer.byteLength + 16 + 12);
          return textsecure.crypto
            .decryptProfile(encrypted, bad_key)
            .catch(function(error) {
              assert.strictEqual(error.name, 'ProfileDecryptError');
            });
        });
    });
  });
});