105 lines
3.8 KiB
TypeScript
105 lines
3.8 KiB
TypeScript
import { Injectable, Logger } from '@nestjs/common';
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import * as crypto from 'crypto';
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@Injectable()
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export class EncryptionService {
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private readonly logger = new Logger(EncryptionService.name);
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private readonly algorithm = 'aes-256-cbc';
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private readonly keyLength = 32; // 256 bits for AES
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private readonly hmacKeyLength = 32; // 256 bits for HMAC
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private readonly ivLength = 16; // 128 bits for CBC
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private readonly hmacLength = 32; // 256 bits for SHA256
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// 从环境变量获取密钥，或使用默认密钥（生产环境必须使用环境变量）
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private readonly encryptionKey: Buffer;
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private readonly hmacKey: Buffer;
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constructor() {
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const encryptionKeyString = process.env.ENCRYPTION_KEY || 'your-default-32-char-aes-secret-key!';
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const hmacKeyString = process.env.HMAC_KEY || 'your-default-32-char-hmac-secret-key';
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this.logger.log(`EncryptionService constructor encryptionKeyString: ${encryptionKeyString}`);
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this.logger.log(`EncryptionService constructor hmacKeyString: ${hmacKeyString}`);
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// 两个独立的密钥
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this.encryptionKey = Buffer.from(encryptionKeyString.slice(0, 32).padEnd(32, '0'), 'utf8');
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this.hmacKey = Buffer.from(hmacKeyString.slice(0, 32).padEnd(32, '0'), 'utf8');
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}
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/**
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* 加密数据
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* @param plaintext 要加密的明文
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* @returns 加密后的base64字符串，格式：iv.ciphertext.hmac
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*/
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encrypt(plaintext: string): string {
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try {
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const iv = crypto.randomBytes(this.ivLength);
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const cipher = crypto.createCipheriv(this.algorithm, this.encryptionKey, iv);
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let ciphertext = cipher.update(plaintext, 'utf8');
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ciphertext = Buffer.concat([ciphertext, cipher.final()]);
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// 计算 HMAC (对 iv + ciphertext 进行HMAC)
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const dataToHmac = Buffer.concat([iv, ciphertext]);
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const hmac = crypto.createHmac('sha256', this.hmacKey);
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hmac.update(dataToHmac);
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const hmacDigest = hmac.digest();
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// 组合 iv + ciphertext + hmac 并编码为base64
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const combined = Buffer.concat([iv, ciphertext, hmacDigest]);
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return combined.toString('base64');
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} catch (error) {
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throw new Error(`加密失败: ${error.message}`);
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}
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}
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/**
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* 解密数据
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* @param encryptedData 加密的base64字符串
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* @returns 解密后的明文
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*/
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decrypt(encryptedData: string): string {
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try {
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const combined = Buffer.from(encryptedData, 'base64');
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// 检查数据长度是否足够
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if (combined.length < this.ivLength + this.hmacLength) {
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throw new Error('加密数据格式无效');
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}
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// 提取 iv, ciphertext, hmac
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const iv = combined.slice(0, this.ivLength);
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const hmacDigest = combined.slice(-this.hmacLength);
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const ciphertext = combined.slice(this.ivLength, -this.hmacLength);
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// 验证 HMAC
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const dataToHmac = Buffer.concat([iv, ciphertext]);
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const hmac = crypto.createHmac('sha256', this.hmacKey);
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hmac.update(dataToHmac);
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const expectedHmac = hmac.digest();
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if (!crypto.timingSafeEqual(hmacDigest, expectedHmac)) {
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throw new Error('HMAC验证失败，数据可能被篡改');
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}
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// 解密
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const decipher = crypto.createDecipheriv(this.algorithm, this.encryptionKey, iv);
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let plaintext = decipher.update(ciphertext, undefined, 'utf8');
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plaintext += decipher.final('utf8');
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return plaintext;
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} catch (error) {
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throw new Error(`解密失败: ${error.message}`);
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}
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}
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/**
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* 生成新的加密密钥（用于初始化）
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* 返回两个独立的密钥
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*/
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generateKey(): { encryptionKey: string; hmacKey: string } {
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return {
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encryptionKey: crypto.randomBytes(this.keyLength).toString('base64'),
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hmacKey: crypto.randomBytes(this.hmacKeyLength).toString('base64')
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};
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}
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}
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