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

• algorithm: <AlgorithmIdentifier> | <EcdhKeyDeriveParams> | <HkdfParams> | <Pbkdf2Params>
• baseKey: <CryptoKey>
• length：<number> | <null> 默认值： null
• 返回：<Promise> 以 <ArrayBuffer> 完成

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.

当未提供 length 或为 null 时，将生成给定算法的最大比特数。这适用于 'ECDH'、'X25519' 和 'X448' 算法，对于其他算法，length 必须是一个数字。

🌐 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 将会被解析为一个包含生成数据的 <ArrayBuffer>。

🌐 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'
• 'X448' ¹
• 'HKDF'
• 'PBKDF2'