subtle.deriveBits(algorithm, baseKey, length)

• algorithm：<AlgorithmIdentifier> | <EcdhKeyDeriveParams> | <HkdfParams> | <Pbkdf2Params>

• baseKey：<CryptoKey>

• length：<number>

• 返回：<Promise> 包含 <ArrayBuffer>

  ¥Returns: <Promise> containing <ArrayBuffer>

使用 algorithm 中指定的方法和参数以及 baseKey 提供的密钥材料，subtle.deriveBits() 尝试生成 length 位。Node.js 实现要求 length 是 8 的倍数。如果成功，返回的 promise 将使用包含生成数据的 <ArrayBuffer> 进行解析。

¥Using the method and parameters specified in algorithm and the keying material provided by baseKey, subtle.deriveBits() attempts to generate length bits. The Node.js implementation requires that length is a multiple of 8. If successful, the returned promise will be resolved with an <ArrayBuffer> containing the generated data.

目前支持的算法包括：

¥The algorithms currently supported include:

• 'ECDH'

• 'HKDF'

• 'PBKDF2'