// Copyright 2023 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

// This is a mirror of proto definitions from Tink Cryptographic library
// https://github.com/google/tink/blob/master/proto/hpke.proto
syntax = "proto2";

package tink;

// Required in Chrome.
option optimize_for = LITE_RUNTIME;

enum HpkeKem {
  KEM_UNKNOWN = 0;
  DHKEM_X25519_HKDF_SHA256 = 1;
  DHKEM_P256_HKDF_SHA256 = 2;
  DHKEM_P384_HKDF_SHA384 = 3;
  DHKEM_P521_HKDF_SHA512 = 4;
}

enum HpkeKdf {
  KDF_UNKNOWN = 0;
  HKDF_SHA256 = 1;
  HKDF_SHA384 = 2;
  HKDF_SHA512 = 3;
}

enum HpkeAead {
  AEAD_UNKNOWN = 0;
  AES_128_GCM = 1;
  AES_256_GCM = 2;
  CHACHA20_POLY1305 = 3;
}

message HpkeParams {
  required HpkeKem kem = 1;
  required HpkeKdf kdf = 2;
  required HpkeAead aead = 3;
}

message HpkePublicKey {
  required uint32 version = 1;
  required HpkeParams params = 2;
  // KEM-encoding of public key (i.e., SerializePublicKey() ) as described in
  // https://www.rfc-editor.org/rfc/rfc9180.html#name-cryptographic-dependencies.
  required bytes public_key = 3;
}