Node.js keyObject.symmetricKeySize属性

keyObject.symmetricKeySize 属性是 crypto 模块内 keyObject 类的内置应用程序接口。它用于查找对称密钥的密钥大小。crypto 模块存在于 Node.js 中，并为 OpenSSL 的哈希、HMAC、加密、解码、签名和验证方法提供了包装器。

语法：

keyObject.symmetricKeySize

返回值: 它返回密钥的大小。对于非对称密钥，返回值为 未定义。

示例:

const { 
    webcrypto: { subtle }, 
    KeyObject, 
} = await import("crypto"); 
  
(async function () { 
    const key = await subtle.generateKey( 
        { 
            name: "HMAC", 
            hash: "SHA-256", 
            length: 256, 
        }, 
        true, 
        ["sign", "verify"] 
    ); 
  
    try { 
        const keyObject = KeyObject.from(key); 
        console.log( 
            keyObject.symmetricKeySize 
        ); 
    } catch (error) { 
        console.log("Error has been occurred"); 
    } 
})(); 

输出：

32

示例：

const { 
 KeyObject, 
 webcrypto: { subtle, getRandomValues } 
} = await import('node:crypto'); 
  
(async function(){ 
    const keyData=getRandomValues(new Uint8Array(16)); 
    const key=await subtle.importKey("raw",keyData,"AES-GCM",false,["encrypt"]) 
    const keyObject = KeyObject.from(key); 
        console.log( 
            keyObject.symmetricKeySize 
        ); 
})(); 

输出:

16

参考： https://nodejs.org/api/crypto.html#keyobjectsymmetrickeysize