subtle.deriveBits(algorithm, baseKey[, length])

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

• baseKey：<CryptoKey>

• length：<number> | <null> 默认值：null

  ¥length: <number> | <null> Default: null

• 返回：<Promise> 满足 <ArrayBuffer>

  ¥Returns: <Promise> Fulfills with an <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。

¥Using the method and parameters specified in algorithm and the keying material provided by baseKey, subtle.deriveBits() attempts to generate length bits.

Node.js 实现要求 length（当数字时）是 8 的倍数。

¥The Node.js implementation requires that length, when a number, is a multiple of 8.

当未提供 length 或 null 时，将生成给定算法的最大位数。这适用于 'ECDH'、'X25519' 和 'X448' 算法，对于其他算法，length 必须为数字。

¥When length is not provided or null the maximum number of bits for a given algorithm is generated. This is allowed for the 'ECDH', 'X25519', and 'X448' algorithms, for other algorithms length is required to be a number.

如果成功，返回的 promise 将使用包含生成数据的 <ArrayBuffer> 进行解析。

¥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'

• 'X25519' ¹

• 'X448' ¹

• 'HKDF'

• 'PBKDF2'