148 lines
4.0 KiB
JavaScript
148 lines
4.0 KiB
JavaScript
/**
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* hybrid_encrypt_js.js
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* 前端混合解密实现，与Go后端的hybrid_encrypt.go配合使用
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*/
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/**
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* 使用RSA私钥和AES-GCM解密数据
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* @param {ArrayBuffer} ciphertext - 加密的数据
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* @param {CryptoKey} privateKey - RSA私钥
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* @returns {Promise<ArrayBuffer>} - 解密后的数据
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*/
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async function hybridDecrypt(ciphertext, privateKey) {
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// 将ArrayBuffer转换为Uint8Array以便处理
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const ciphertextArray = new Uint8Array(ciphertext);
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// 获取RSA密钥大小（字节）
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const keySize = getPrivateKeySize(privateKey);
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// 检查密文长度是否足够
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if (ciphertextArray.length < keySize + 12) {
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throw new Error('密文太短');
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}
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// 分解密文各部分
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const encryptedKey = ciphertextArray.slice(0, keySize);
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const nonce = ciphertextArray.slice(keySize, keySize + 12);
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const data = ciphertextArray.slice(keySize + 12);
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// 使用RSA私钥解密AES密钥
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const aesKeyBuffer = await window.crypto.subtle.decrypt(
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{
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name: 'RSA-OAEP',
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hash: { name: 'SHA-256' },
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},
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privateKey,
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encryptedKey
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);
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// 使用AES密钥和GCM模式解密数据
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const aesKey = await window.crypto.subtle.importKey(
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'raw',
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aesKeyBuffer,
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{ name: 'AES-GCM', length: 256 },
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false,
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['decrypt']
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);
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const plaintext = await window.crypto.subtle.decrypt(
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{
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name: 'AES-GCM',
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iv: nonce,
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},
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aesKey,
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data
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);
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return plaintext;
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}
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/**
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* 从PEM格式导入RSA私钥
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* @param {string} pemString - PEM格式的私钥字符串
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* @returns {Promise<CryptoKey>} - 导入的RSA私钥
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*/
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async function importPrivateKeyFromPEM(pemString) {
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// 移除PEM头尾和换行符
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const pemContents = pemString
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.replace('-----BEGIN RSA PRIVATE KEY-----', '')
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.replace('-----END RSA PRIVATE KEY-----', '')
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.replace(/\s+/g, '');
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// Base64解码
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const binaryDer = window.atob(pemContents);
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const derArray = new Uint8Array(binaryDer.length);
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for (let i = 0; i < binaryDer.length; i++) {
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derArray[i] = binaryDer.charCodeAt(i);
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}
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// 导入私钥
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const privateKey = await window.crypto.subtle.importKey(
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'pkcs8',
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derArray.buffer,
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{
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name: 'RSA-OAEP',
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hash: { name: 'SHA-256' },
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},
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false,
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['decrypt']
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);
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return privateKey;
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}
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/**
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* 获取RSA私钥的大小（字节）
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* @param {CryptoKey} privateKey - RSA私钥
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* @returns {number} - 密钥大小（字节）
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*/
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function getPrivateKeySize(privateKey) {
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// 在实际应用中，可能需要从privateKey对象中提取密钥大小
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// 这里简化处理，假设使用2048位RSA密钥（256字节）
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return 256; // 2048位 / 8 = 256字节
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}
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/**
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* 解密Base64编码的混合加密图片数据
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* @param {string} base64Data - Base64编码的加密图片数据
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* @param {string} privateKeyPEM - PEM格式的RSA私钥
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* @returns {Promise<string>} - 解密后的图片Base64字符串
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*/
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async function decryptImage(base64Data, privateKeyPEM) {
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try {
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// 解码Base64
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const binaryString = window.atob(base64Data);
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const bytes = new Uint8Array(binaryString.length);
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for (let i = 0; i < binaryString.length; i++) {
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bytes[i] = binaryString.charCodeAt(i);
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}
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// 导入私钥
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const privateKey = await importPrivateKeyFromPEM(privateKeyPEM);
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// 解密数据
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const decryptedData = await hybridDecrypt(bytes.buffer, privateKey);
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// 将解密后的图片数据转换为Base64
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const decryptedArray = new Uint8Array(decryptedData);
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let binary = '';
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for (let i = 0; i < decryptedArray.length; i++) {
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binary += String.fromCharCode(decryptedArray[i]);
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}
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// 返回带有MIME类型的Base64图片数据
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// 注意：这里假设是JPEG图片，实际应用中可能需要根据图片类型动态设置
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return 'data:image/jpeg;base64,' + window.btoa(binary);
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} catch (error) {
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console.error('图片解密失败:', error);
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throw error;
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}
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}
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// 导出函数
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export {
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hybridDecrypt,
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importPrivateKeyFromPEM,
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decryptImage
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}; |