A CryptoKey object can be obtained using SubtleCrypto.generateKey(), SubtleCrypto.deriveKey() （从另一个CryptoKey生成）or SubtleCrypto.importKey() （从其它格式）
// extractable ： 能否提取（SubtleCrypto.exportKey => ArrayBuffer），usages： 用途, 之间允许的key生成算法可能不一样
crypto.subtle.generateKey(
{ name: "ECDH", namedCurve: "P-256" },
true, // false for production
['deriveBits'])
//crypto 另外一个属性
var array = new Uint32Array(10);
window.crypto.getRandomValues(array);
SHA-256算法字符串哈希值
====
function sha256(str) {
// We transform the string into an arraybuffer.
var buffer = new TextEncoder("utf-8").encode(str);
return crypto.subtle.digest("SHA-256", buffer).then(hash => {
// 返回数组缓存
return hex(hash);
});
}
function hex(buffer) { // 转成16进制
var hexCodes = [];
var view = new DataView(buffer);
for (var i = 0; i < view.byteLength; i += 4) {
// Using getUint32 reduces the number of iterations needed (we process 4 bytes each time)
var value = view.getUint32(i)
// toString(16) will give the hex representation of the number without padding
var stringValue = value.toString(16)
// We use concatenation and slice for padding.
var padding = '00000000'
var paddedValue = (padding + stringValue).slice(-padding.length)
hexCodes.push(paddedValue);
}
// Join all the hex strings into one
return hexCodes.join("");
}
sha256("foobar").then(function(digest) {
console.log(digest);
}); // outputs “c3ab8ff13720e8ad9047dd39466b3c8974e592c2fa383d4a3960714caef0c4f2"
