WebCrypto HKDF 会话密钥派生与短期加密实践

概述HKDF 适合从主密钥派生短期会话密钥。本文展示派生与加解密流程。派生与加解密const supportsSubtle = !!(crypto && crypto.subtle); async function deriveHKDF(secretRaw, salt, info = 'session') { const enc = new TextEncoder(); const base = await crypto.subtle.importKey('raw', secretRaw, 'HKDF', false, ['deriveKey']); const key = await crypto.subtle.deriveKey({ name: 'HKDF', hash: 'SHA-256', salt: enc.encode(salt), info: enc.encode(info) }, base, { name: 'AES-GCM', length: 256 }, true, ['encrypt','decrypt']); return key; } async function encrypt(key, bytes) { const iv = crypto.getRandomValues(new Uint8Array(12)); const buf = await crypto.subtle.encrypt({ name: 'AES-GCM', iv }, key, bytes); return { iv, cipher: new Uint8Array(buf) }; } async function decrypt(key, iv, cipher) { const buf = await crypto.subtle.decrypt({ name: 'AES-GCM', iv }, key, cipher); return new Uint8Array(buf); }