api接口安全策略：签名和加密原理-后端验证签名原理
2019-03-25 本文已影响1人
瑟闻风倾
1. 安全概述
一般的接口是裸露的、不安全的！使用post、get模拟可以轻松对api进行请求，最简单的攻击就可以瞬间完成近万会员的注册！所以在进行api接口通讯的同时我们应该进行数据的验证工作！
2. 加密原理及流程(自定义)
2.1 从服务器端获取一个唯一性的token，我们称之为 accessToken;
2.2 前端对accessToken进行随机性拆分及md5加密,产生签名（保存在本地存储中）;
2.3 前端在与后端进行交互时传递签名;
2.4 后端接收数据是验证签名;
3. 签名准备
3.1 前端(uni-app)-主要理解签名函数
(1)md5.js (对字符串进行md5 加密)
var hexcase = 0; /* hex output format. 0 - lowercase; 1 - uppercase */
var b64pad = ""; /* base-64 pad character. "=" for strict RFC compliance */
/*
* These are the functions you'll usually want to call
* They take string arguments and return either hex or base-64 encoded strings
* md5 加密 ：该文件用于对字符串进行md5加密
*/
function hex_md5(s) { return rstr2hex(rstr_md5(str2rstr_utf8(s))); }
function b64_md5(s) { return rstr2b64(rstr_md5(str2rstr_utf8(s))); }
function any_md5(s, e) { return rstr2any(rstr_md5(str2rstr_utf8(s)), e); }
function hex_hmac_md5(k, d)
{ return rstr2hex(rstr_hmac_md5(str2rstr_utf8(k), str2rstr_utf8(d))); }
function b64_hmac_md5(k, d)
{ return rstr2b64(rstr_hmac_md5(str2rstr_utf8(k), str2rstr_utf8(d))); }
function any_hmac_md5(k, d, e)
{ return rstr2any(rstr_hmac_md5(str2rstr_utf8(k), str2rstr_utf8(d)), e); }
/*
* Perform a simple self-test to see if the VM is working
*/
function md5_vm_test()
{
return hex_md5("abc").toLowerCase() == "900150983cd24fb0d6963f7d28e17f72";
}
/*
* Calculate the MD5 of a raw string
*/
function rstr_md5(s)
{
return binl2rstr(binl_md5(rstr2binl(s), s.length * 8));
}
/*
* Calculate the HMAC-MD5, of a key and some data (raw strings)
*/
function rstr_hmac_md5(key, data)
{
var bkey = rstr2binl(key);
if(bkey.length > 16) bkey = binl_md5(bkey, key.length * 8);
var ipad = Array(16), opad = Array(16);
for(var i = 0; i < 16; i++)
{
ipad[i] = bkey[i] ^ 0x36363636;
opad[i] = bkey[i] ^ 0x5C5C5C5C;
}
var hash = binl_md5(ipad.concat(rstr2binl(data)), 512 + data.length * 8);
return binl2rstr(binl_md5(opad.concat(hash), 512 + 128));
}
/*
* Convert a raw string to a hex string
*/
function rstr2hex(input)
{
try { hexcase } catch(e) { hexcase=0; }
var hex_tab = hexcase ? "0123456789ABCDEF" : "0123456789abcdef";
var output = "";
var x;
for(var i = 0; i < input.length; i++)
{
x = input.charCodeAt(i);
output += hex_tab.charAt((x >>> 4) & 0x0F)
+ hex_tab.charAt( x & 0x0F);
}
return output;
}
/*
* Convert a raw string to a base-64 string
*/
function rstr2b64(input)
{
try { b64pad } catch(e) { b64pad=''; }
var tab = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
var output = "";
var len = input.length;
for(var i = 0; i < len; i += 3)
{
var triplet = (input.charCodeAt(i) << 16)
| (i + 1 < len ? input.charCodeAt(i+1) << 8 : 0)
| (i + 2 < len ? input.charCodeAt(i+2) : 0);
for(var j = 0; j < 4; j++)
{
if(i * 8 + j * 6 > input.length * 8) output += b64pad;
else output += tab.charAt((triplet >>> 6*(3-j)) & 0x3F);
}
}
return output;
}
/*
* Convert a raw string to an arbitrary string encoding
*/
function rstr2any(input, encoding)
{
var divisor = encoding.length;
var i, j, q, x, quotient;
/* Convert to an array of 16-bit big-endian values, forming the dividend */
var dividend = Array(Math.ceil(input.length / 2));
for(i = 0; i < dividend.length; i++)
{
dividend[i] = (input.charCodeAt(i * 2) << 8) | input.charCodeAt(i * 2 + 1);
}
/*
* Repeatedly perform a long division. The binary array forms the dividend,
* the length of the encoding is the divisor. Once computed, the quotient
* forms the dividend for the next step. All remainders are stored for later
* use.
*/
var full_length = Math.ceil(input.length * 8 /
(Math.log(encoding.length) / Math.log(2)));
var remainders = Array(full_length);
for(j = 0; j < full_length; j++)
{
quotient = Array();
x = 0;
for(i = 0; i < dividend.length; i++)
{
x = (x << 16) + dividend[i];
q = Math.floor(x / divisor);
x -= q * divisor;
if(quotient.length > 0 || q > 0)
quotient[quotient.length] = q;
}
remainders[j] = x;
dividend = quotient;
}
/* Convert the remainders to the output string */
var output = "";
for(i = remainders.length - 1; i >= 0; i--)
output += encoding.charAt(remainders[i]);
return output;
}
/*
* Encode a string as utf-8.
* For efficiency, this assumes the input is valid utf-16.
*/
function str2rstr_utf8(input)
{
var output = "";
var i = -1;
var x, y;
while(++i < input.length)
{
/* Decode utf-16 surrogate pairs */
x = input.charCodeAt(i);
y = i + 1 < input.length ? input.charCodeAt(i + 1) : 0;
if(0xD800 <= x && x <= 0xDBFF && 0xDC00 <= y && y <= 0xDFFF)
{
x = 0x10000 + ((x & 0x03FF) << 10) + (y & 0x03FF);
i++;
}
/* Encode output as utf-8 */
if(x <= 0x7F)
output += String.fromCharCode(x);
else if(x <= 0x7FF)
output += String.fromCharCode(0xC0 | ((x >>> 6 ) & 0x1F),
0x80 | ( x & 0x3F));
else if(x <= 0xFFFF)
output += String.fromCharCode(0xE0 | ((x >>> 12) & 0x0F),
0x80 | ((x >>> 6 ) & 0x3F),
0x80 | ( x & 0x3F));
else if(x <= 0x1FFFFF)
output += String.fromCharCode(0xF0 | ((x >>> 18) & 0x07),
0x80 | ((x >>> 12) & 0x3F),
0x80 | ((x >>> 6 ) & 0x3F),
0x80 | ( x & 0x3F));
}
return output;
}
/*
* Encode a string as utf-16
*/
function str2rstr_utf16le(input)
{
var output = "";
for(var i = 0; i < input.length; i++)
output += String.fromCharCode( input.charCodeAt(i) & 0xFF,
(input.charCodeAt(i) >>> 8) & 0xFF);
return output;
}
function str2rstr_utf16be(input)
{
var output = "";
for(var i = 0; i < input.length; i++)
output += String.fromCharCode((input.charCodeAt(i) >>> 8) & 0xFF,
input.charCodeAt(i) & 0xFF);
return output;
}
/*
* Convert a raw string to an array of little-endian words
* Characters >255 have their high-byte silently ignored.
*/
function rstr2binl(input)
{
var output = Array(input.length >> 2);
for(var i = 0; i < output.length; i++)
output[i] = 0;
for(var i = 0; i < input.length * 8; i += 8)
output[i>>5] |= (input.charCodeAt(i / 8) & 0xFF) << (i%32);
return output;
}
/*
* Convert an array of little-endian words to a string
*/
function binl2rstr(input)
{
var output = "";
for(var i = 0; i < input.length * 32; i += 8)
output += String.fromCharCode((input[i>>5] >>> (i % 32)) & 0xFF);
return output;
}
/*
* Calculate the MD5 of an array of little-endian words, and a bit length.
*/
function binl_md5(x, len)
{
/* append padding */
x[len >> 5] |= 0x80 << ((len) % 32);
x[(((len + 64) >>> 9) << 4) + 14] = len;
var a = 1732584193;
var b = -271733879;
var c = -1732584194;
var d = 271733878;
for(var i = 0; i < x.length; i += 16)
{
var olda = a;
var oldb = b;
var oldc = c;
var oldd = d;
a = md5_ff(a, b, c, d, x[i+ 0], 7 , -680876936);
d = md5_ff(d, a, b, c, x[i+ 1], 12, -389564586);
c = md5_ff(c, d, a, b, x[i+ 2], 17, 606105819);
b = md5_ff(b, c, d, a, x[i+ 3], 22, -1044525330);
a = md5_ff(a, b, c, d, x[i+ 4], 7 , -176418897);
d = md5_ff(d, a, b, c, x[i+ 5], 12, 1200080426);
c = md5_ff(c, d, a, b, x[i+ 6], 17, -1473231341);
b = md5_ff(b, c, d, a, x[i+ 7], 22, -45705983);
a = md5_ff(a, b, c, d, x[i+ 8], 7 , 1770035416);
d = md5_ff(d, a, b, c, x[i+ 9], 12, -1958414417);
c = md5_ff(c, d, a, b, x[i+10], 17, -42063);
b = md5_ff(b, c, d, a, x[i+11], 22, -1990404162);
a = md5_ff(a, b, c, d, x[i+12], 7 , 1804603682);
d = md5_ff(d, a, b, c, x[i+13], 12, -40341101);
c = md5_ff(c, d, a, b, x[i+14], 17, -1502002290);
b = md5_ff(b, c, d, a, x[i+15], 22, 1236535329);
a = md5_gg(a, b, c, d, x[i+ 1], 5 , -165796510);
d = md5_gg(d, a, b, c, x[i+ 6], 9 , -1069501632);
c = md5_gg(c, d, a, b, x[i+11], 14, 643717713);
b = md5_gg(b, c, d, a, x[i+ 0], 20, -373897302);
a = md5_gg(a, b, c, d, x[i+ 5], 5 , -701558691);
d = md5_gg(d, a, b, c, x[i+10], 9 , 38016083);
c = md5_gg(c, d, a, b, x[i+15], 14, -660478335);
b = md5_gg(b, c, d, a, x[i+ 4], 20, -405537848);
a = md5_gg(a, b, c, d, x[i+ 9], 5 , 568446438);
d = md5_gg(d, a, b, c, x[i+14], 9 , -1019803690);
c = md5_gg(c, d, a, b, x[i+ 3], 14, -187363961);
b = md5_gg(b, c, d, a, x[i+ 8], 20, 1163531501);
a = md5_gg(a, b, c, d, x[i+13], 5 , -1444681467);
d = md5_gg(d, a, b, c, x[i+ 2], 9 , -51403784);
c = md5_gg(c, d, a, b, x[i+ 7], 14, 1735328473);
b = md5_gg(b, c, d, a, x[i+12], 20, -1926607734);
a = md5_hh(a, b, c, d, x[i+ 5], 4 , -378558);
d = md5_hh(d, a, b, c, x[i+ 8], 11, -2022574463);
c = md5_hh(c, d, a, b, x[i+11], 16, 1839030562);
b = md5_hh(b, c, d, a, x[i+14], 23, -35309556);
a = md5_hh(a, b, c, d, x[i+ 1], 4 , -1530992060);
d = md5_hh(d, a, b, c, x[i+ 4], 11, 1272893353);
c = md5_hh(c, d, a, b, x[i+ 7], 16, -155497632);
b = md5_hh(b, c, d, a, x[i+10], 23, -1094730640);
a = md5_hh(a, b, c, d, x[i+13], 4 , 681279174);
d = md5_hh(d, a, b, c, x[i+ 0], 11, -358537222);
c = md5_hh(c, d, a, b, x[i+ 3], 16, -722521979);
b = md5_hh(b, c, d, a, x[i+ 6], 23, 76029189);
a = md5_hh(a, b, c, d, x[i+ 9], 4 , -640364487);
d = md5_hh(d, a, b, c, x[i+12], 11, -421815835);
c = md5_hh(c, d, a, b, x[i+15], 16, 530742520);
b = md5_hh(b, c, d, a, x[i+ 2], 23, -995338651);
a = md5_ii(a, b, c, d, x[i+ 0], 6 , -198630844);
d = md5_ii(d, a, b, c, x[i+ 7], 10, 1126891415);
c = md5_ii(c, d, a, b, x[i+14], 15, -1416354905);
b = md5_ii(b, c, d, a, x[i+ 5], 21, -57434055);
a = md5_ii(a, b, c, d, x[i+12], 6 , 1700485571);
d = md5_ii(d, a, b, c, x[i+ 3], 10, -1894986606);
c = md5_ii(c, d, a, b, x[i+10], 15, -1051523);
b = md5_ii(b, c, d, a, x[i+ 1], 21, -2054922799);
a = md5_ii(a, b, c, d, x[i+ 8], 6 , 1873313359);
d = md5_ii(d, a, b, c, x[i+15], 10, -30611744);
c = md5_ii(c, d, a, b, x[i+ 6], 15, -1560198380);
b = md5_ii(b, c, d, a, x[i+13], 21, 1309151649);
a = md5_ii(a, b, c, d, x[i+ 4], 6 , -145523070);
d = md5_ii(d, a, b, c, x[i+11], 10, -1120210379);
c = md5_ii(c, d, a, b, x[i+ 2], 15, 718787259);
b = md5_ii(b, c, d, a, x[i+ 9], 21, -343485551);
a = safe_add(a, olda);
b = safe_add(b, oldb);
c = safe_add(c, oldc);
d = safe_add(d, oldd);
}
return Array(a, b, c, d);
}
/*
* These functions implement the four basic operations the algorithm uses.
*/
function md5_cmn(q, a, b, x, s, t)
{
return safe_add(bit_rol(safe_add(safe_add(a, q), safe_add(x, t)), s),b);
}
function md5_ff(a, b, c, d, x, s, t)
{
return md5_cmn((b & c) | ((~b) & d), a, b, x, s, t);
}
function md5_gg(a, b, c, d, x, s, t)
{
return md5_cmn((b & d) | (c & (~d)), a, b, x, s, t);
}
function md5_hh(a, b, c, d, x, s, t)
{
return md5_cmn(b ^ c ^ d, a, b, x, s, t);
}
function md5_ii(a, b, c, d, x, s, t)
{
return md5_cmn(c ^ (b | (~d)), a, b, x, s, t);
}
/*
* Add integers, wrapping at 2^32. This uses 16-bit operations internally
* to work around bugs in some JS interpreters.
*/
function safe_add(x, y)
{
var lsw = (x & 0xFFFF) + (y & 0xFFFF);
var msw = (x >> 16) + (y >> 16) + (lsw >> 16);
return (msw << 16) | (lsw & 0xFFFF);
}
/*
* Bitwise rotate a 32-bit number to the left.
*/
function bit_rol(num, cnt)
{
return (num << cnt) | (num >>> (32 - cnt));
}
module.exports = {
hex_md5 : hex_md5
}
(2)sign.js (签名函数)
var md5 = require('./md5.js');
/**
* 签名函数：与服务器进行交互与md5加密
*/
module.exports = {
sign : function(apiServer){
// 环境判断非uni环境不支持（get、post模拟工具模拟不出来uni变量，实现了接口安全）
if(!uni){return '...';}
console.log('开始签名');
// 连接服务器获取一个临时的accessToken
uni.request({
url: apiServer+'getAccessToken',
method: 'GET',
success: res => {
console.log(res);
if(res.data.status != 'ok'){return ;}
var data = res.data.data;
// 对 accessToken 进行md5加密（token和当前时间戳组合后加密）
var accessToken = md5.hex_md5(data.token + data.time);
// 签名 = md5(accessToekn + time) + '-' + 'accessToekn';
var sign = accessToken + '-' + data.token;
//console.log(sign);
// 记录在本地
uni.setStorage({
key:"sign",
data:sign
});
console.log('签名完成');
},
fail:function(e){
console.log(JSON.stringify(e));
}
});
}
}
3.2 数据库-创建数据表存放临时token
DROP TABLE IF EXISTS `yuedu_access_tokens`;
CREATE TABLE `yuedu_access_tokens` (
`token` varchar(30) NOT NULL,
`time` int(11) DEFAULT NULL,
PRIMARY KEY (`token`)
) ENGINE=MyISAM DEFAULT CHARSET=utf8mb4;
3.3 后端(php)
(1)表中插入生成的token
<?php
//getAccessToken.php
namespace hsC;
class getAccessToken{
public function index(){
//连接数据库获取access_tokens数据表对象
$db = \hsTool\db::getInstance("access_tokens");
//uniqid()生成唯一的不重复的字符串，time()生成当前时间戳
$token = array(
'token' => uniqid(),
'time' => time()
);
$db->add($token);//记录写入到数据库
exit(jsonCode('ok'),$token);//返回token
}
}
?>
(2)签名验证-后端验证签名原理
//签名验证
function checkSign(){
if(empty($_POST['sign'])){exit(jsonCode('error', 'sign error'));}
$sign = explode('-', $_POST['sign']);
if(count($sign) != 2){exit(jsonCode('error', 'sign error'));}
$db = \hsTool\db::getInstance('access_tokens');
$token = $db->where('token = ?', array($sign[1]))->fetch();
if(empty($token)){exit(jsonCode('error', 'sign error'));}
$signMd5 = md5($token['token'].$token['time']);
if($signMd5 != $sign[0]){exit(jsonCode('error', 'sign error'));}
// 验证成功则删除
$db->where('token = ?', array($sign[1]))->delete();
}
4. 使用说明
在数据提交页面提交之前进行预签名，提交数据时携带此签名！
//options为登录验证时若需进行登录时传的参数
onLoad:function(options){
sign.sign(this.apiServer);//预签名：获取签名并保存在本地
//console.log(options)
_self = this;
pageOptions = options
//条件编译：判断对应平台
// #ifdef MP-WEIXIN
//微信端登录
uni.login({
success:function(res){
console.log(res)
uni.request({
url: _self.apiServer + 'member&m=codeToSession&code=' + res.code,
method: 'GET',
//data: {},
success: res => {
console.log(res)
session_key = res.data.session_key;
openid = res.data.openid;
}
});
}
})
// #endif
// #ifdef APP-PLUS
//app端(微信第三方)登录:手册位置 https://uniapp.dcloud.io/api/plugins/login?id=getuserinfo
uni.login({
provider: 'weixin',//默认登录提供商是微信，可省略（也可以开发微博、qq等的同步登录）
success:function(loginRes){
//console.log(JSON.stringify(loginRes))//对象转json
//console.log(JSON.stringify(loginRes.authResult));//authResult对象存放的是和对应平台相关的敏感信息
uni.getUserInfo({
success:function(infoRes){//userInfo存放基本的用户信息,
//console.log(JSON.stringify(infoRes));
//console.log('用户昵称为:' + infoRes.userInfo.nickName);
var sign = uni.getStorageSync('sign');
// 与服务器交互将数据提交到服务端数据库
uni.request({
url: _self.apiServer+'member&m=login',
method: 'POST',
header: {'content-type' : "application/x-www-form-urlencoded"},
data: {
openid : infoRes.userInfo.openId,
name : infoRes.userInfo.nickName,
face : infoRes.userInfo.avatarUrl,
sign : sign
},
success: res => {
console.log(JSON.stringify(res));
res = res.data;
if(res.status == "ok"){
uni.showToast({title:"登录成功后存储用户信息并跳转"});
uni.setStorageSync('SUID',res.data.u_id + '');
uni.setStorageSync('SRAND',res.data.u_random + '');
uni.setStorageSync('SNAME',res.data.u_name + '');
uni.setStorageSync('SFACE',res.data.u_face + '');
if(options.backtype == 1){
uni.redirectTo({url:options.backpage});
}else{
uni.switchTab({url:options.backpage});
}
}else{
uni.showToast({title:'登录失败:' + res.data});
}
},
fail: () => {},
complete: () => {}
});
},
fail:function(){
uni.showToast({title:"微信登录授权失败",icon:"none"});
}
})
},
fail:function(){
uni.showToast({title:"微信登录授权失败",icon:"none"});
}
})
// #endif
}
5. 更合理的签名保存
(1)此处使用数据库保存了accessToken，会降低数据库的性能：每一个token都会连接数据库去读取和生成；如果只是预签名没有提交，但也会放在数据表中产生垃圾数据。
(2)更好的方式是使用redis 或 memcache来保存token和time，优点是不仅变量会自动失效而且查询效率高：redis 或 memcache的所有变量都有有效期，可以设置变量有效期并能隔段时间自动失效，符合accessToken的生命周期；redis 或 memcache的保存是基于内存的，不需要连接数据库，查询效率高。
