> For the complete documentation index, see [llms.txt](https://easonwang.gitbook.io/web_advance/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://easonwang.gitbook.io/web_advance/cryptojia_mi.md).

# Crypto加密

## Crypto加密

## 簡單字串加密

```
let cipher = crypto.createCipher('aes-256-cbc','testkey');
let crypted = cipher.update('要加密的東西','utf8','hex');
crypted += cipher.final('hex');
```

解密

```
let decipher = crypto.createDecipher('aes-256-cbc','testkey');
let dec = decipher.update(crypted,'hex','utf8');
dec += decipher.final('utf8');
console.log('解密的文本：'+dec);
```

注意：如果產生錯誤

> TypeError: error:0606506D:digital envelope routines:EVP\_DecryptFinal\_ex:wrong final block length

可把`'hex'`改為`'binary'`試試

## JWT Token產生

<https://github.com/auth0/node-jsonwebtoken>

Server

> 以下為預設的HMAC加密，第二個參數放入secret，可以放入客戶password

```javascript
// Generate JWT token
const jwt = require('jsonwebtoken');
const token = jwt.sign(result.rows[0], result.rows[0].password);
console.log(token)
```

Client

> 登入時驗證password正確，token從localstorage等地方取出。

```javascript
const decoded = jwt.verify(token, result.rows[0].password);
console.log(decoded) // bar
```

如果客戶端已經有Token則直接使用密碼與verify解密即可驗證，不用再次去DB query。


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