crypto.ts

// Copyright 2019 Google LLC
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//      http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
/* global window */

import {BrowserCrypto} from './browser/crypto';
import {NodeCrypto} from './node/crypto';

export interface JwkCertificate {
  kty: string;
  alg: string;
  use?: string;
  kid: string;
  n: string;
  e: string;
}

export interface CryptoSigner {
  update(data: string): void;
  sign(key: string, outputFormat: string): string;
}

// Crypto interface will provide required crypto functions.
// Use `createCrypto()` factory function to create an instance
// of Crypto. It will either use Node.js `crypto` module, or
// use browser's SubtleCrypto interface. Since most of the
// SubtleCrypto methods return promises, we must make those
// methods return promises here as well, even though in Node.js
// they are synchronous.
export interface Crypto {
  sha256DigestBase64(str: string): Promise<string>;
  randomBytesBase64(n: number): string;
  verify(
    pubkey: string | JwkCertificate,
    data: string | Buffer,
    signature: string
  ): Promise<boolean>;
  sign(
    privateKey: string | JwkCertificate,
    data: string | Buffer
  ): Promise<string>;
  decodeBase64StringUtf8(base64: string): string;
  encodeBase64StringUtf8(text: string): string;
}

export function createCrypto(): Crypto {
  if (hasBrowserCrypto()) {
    return new BrowserCrypto();
  }
  return new NodeCrypto();
}

export function hasBrowserCrypto() {
  return (
    typeof window !== 'undefined' &&
    typeof window.crypto !== 'undefined' &&
    typeof window.crypto.subtle !== 'undefined'
  );
}