Method AesEncryptImpl

be/src/exprs/string-functions.cc:548–587

An entrypoint to perform AES encryption on a given expression string. In contrast to AesDecryptImpl(), it does not support ECB modes. For other details, see the comment at AesDecryptImpl().

// to AesDecryptImpl(), it does not support ECB modes. For other details, see the
// comment at AesDecryptImpl().
StringVal StringFunctions::AesEncryptImpl(FunctionContext* ctx, const StringVal& expr,
    const StringVal& key, const StringVal& mode, const StringVal& iv) {
  if (expr.is_null) {
    return StringVal::null();
  }
  EncryptionKey encryption_key;
  Status status = InitializeEncryptionKey(ctx, expr, key, mode, iv, true,
      &encryption_key);
  if (!status.ok()) {
    ctx->SetError(status.msg().msg().data());
    return StringVal::null();
  }

  // Calculate expected output length
  int expected_out_len = expr.len;

  // Append space for gcm_tag in case of GCM mode
  if (encryption_key.IsGcmMode()) {
    expected_out_len += AES_BLOCK_SIZE;
  }

  // Allocate buffer for output
  StringVal result = StringVal(ctx, expected_out_len);
  // Encrypt the input
  int64_t out_len = 0;
  status = encryption_key.Encrypt(expr.ptr, expr.len, result.ptr,
      &out_len);
  if (!status.ok()) {
    ctx->SetError("AES encryption failed.");
    return StringVal::null();
  }
  // Append gcm_tag to encrypted buffer
  if (encryption_key.IsGcmMode()) {
    encryption_key.GetGcmTag(result.ptr + out_len);
    out_len += AES_BLOCK_SIZE;
  }
  // Ensure expected output length matches actual output length
  DCHECK_EQ(expected_out_len, out_len);
  return result;
}
}