JS-RSA请求数据加密

　　最近公司要对前端请求数据进行RSA加密，所以在网上找了一些博客，并下载了一些demo测试了下，但不太乐观。目前网上的绝大部分博客对超长字符串（117位以上）加密不太支持或者支持的不太好。即使是付费的。。。

　　所以我在网上的demo基础上，请教了下算法同学，经过测试，发现转化位二进制后，若第一位为0则会出现位数不够，同时导致解密失败。所以在原来的基础上进行了改进。

一、引入js文件（下载地址：这里）

js/jsencrypt.min.js

二、生产公私钥

这一步的话，可以直接在网上找在线生成。

三、定义方法

这里需要重新定义两个方法：超长加密（encryptLong2）、超长解密（decryptLong2）

let encrypt = new JSEncrypt();  //  声明变量
    let b64map = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
    let b64pad = "=";

JSEncrypt.prototype.encryptLong2 = function (string) {
    var k = this.getKey();
    try {
        var lt = "";
        var ct = "";
        //RSA每次加密117bytes，需要辅助方法判断字符串截取位置
        //1.获取字符串截取点
        var bytes = new Array();
        bytes.push(0);
        var byteNo = 0;
        var len, c;
        len = string.length;
        var temp = 0;
        for (var i = 0; i < len; i++) {
            c = string.charCodeAt(i);
            if (c >= 0x010000 && c <= 0x10FFFF) {
                byteNo += 4;
            } else if (c >= 0x000800 && c <= 0x00FFFF) {
                byteNo += 3;
            } else if (c >= 0x000080 && c <= 0x0007FF) {
                byteNo += 2;
            } else {
                byteNo += 1;
            }
            if ((byteNo % 117) >= 114 || (byteNo % 117) == 0) {
                if (byteNo - temp >= 114) {
                    bytes.push(i);
                    temp = byteNo;
                }
            }
        }
        //2.截取字符串并分段加密
        if (bytes.length > 1) {
            for (var i = 0; i < bytes.length - 1; i++) {
                var str;
                if (i == 0) {
                    str = string.substring(0, bytes[i + 1] + 1);
                } else {
                    str = string.substring(bytes[i] + 1, bytes[i + 1] + 1);
                }
                var t1 = k.encrypt(str);
                ct += addPreZero(t1,256);
            }
            ;
            if (bytes[bytes.length - 1] != string.length - 1) {
                var lastStr = string.substring(bytes[bytes.length - 1] + 1);
   let rsaStr = k.encrypt(lastStr)                
                ct += addPreZero(rsaStr,256);
            }
//console.log("加密完的数据："+ct);
            return hex2b64(ct);
        }
        var t = k.encrypt(string);
        var y = hex2b64(t);
        return y;
    } catch (ex) {
        return false;
    }
}
JSEncrypt.prototype.decryptLong2 = function (string) {
    var k = this.getKey();
    // var maxLength = ((k.n.bitLength()+7)>>3);
    var MAX_DECRYPT_BLOCK = 128;
    try {
        var ct = "";
        var t1;
        var bufTmp;
        var hexTmp;
        var str = b64tohex(string);
        var buf = hexToBytes(str);
        var inputLen = buf.length;
        //开始长度
        var offSet = 0;
        //结束长度
        var endOffSet = MAX_DECRYPT_BLOCK;

        //分段解密
        console.log(inputLen +"----"+offSet)
        while (inputLen - offSet > 0) {
            if (inputLen - offSet > MAX_DECRYPT_BLOCK) {
                bufTmp = buf.slice(offSet, endOffSet); 
   hexTmp = bytesToHex(bufTmp);
                t1 = k.decrypt(hexTmp);
                ct += t1;

            } else {
                bufTmp = buf.slice(offSet, inputLen);
   hexTmp = bytesToHex(bufTmp);
                t1 = k.decrypt(hexTmp);
                ct += t1;

            }
            offSet += MAX_DECRYPT_BLOCK;
            endOffSet += MAX_DECRYPT_BLOCK;
        }
        return ct;
    } catch (ex) {
        return false;
    }
}

四、加密

// 配置公钥
encrypt.setPublicKey('MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQCSLZqlbJchBRpyoBe1pWuoxV3At36hG85G3LikI7fiMRynou9nYz4a4T6uCtJNecFGdMPWPKtZ29/amgeFcHw/5vVEHuo8/JLFDM7u4P+cwTtBMwtsQCgynejfB0aOEp4NYjZTMmaeyRWCo5HOQahuV9LORyH/dWdD948qFsIFcQIDAQAB');    //    这里是配置公钥

// 声明超长字符串

let str = '{"latitude":"30.685632","longitude":"104.074092","appKey":"123412341234","channelId":"12341234","custId":"LASDFASWERSDFASDFASD","telephone":"2341234211234","token":"68d6a4c21170469289c42386b519612c","name":"王十二"}'
// 加密

var encryptData = encrypt.encryptLong2(str)　　//　　encryptData 为加密后的数据

五、解密

// 配置私钥
encrypt.setPrivateKey('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');
// 解密
var  str2 = encrypt.decryptLong2(encryptData);   //strs 为解密后数据，看看是否一致

注：在定义方法时，需引入以下方法

function hex2b64(h) {
        var i;
        var c;
        var ret = "";
        for (i = 0; i + 3 <= h.length; i += 3) {
            c = parseInt(h.substring(i, i + 3), 16);
            ret += b64map.charAt(c >> 6) + b64map.charAt(c & 63);
        }
        if (i + 1 == h.length) {
            c = parseInt(h.substring(i, i + 1), 16);
            ret += b64map.charAt(c << 2);
        }
        else if (i + 2 == h.length) {
            c = parseInt(h.substring(i, i + 2), 16);
            ret += b64map.charAt(c >> 2) + b64map.charAt((c & 3) << 4);
        }
        while ((ret.length & 3) > 0) ret += b64pad;
        return ret;
    }
    function hexToBytes(hex) {
        for (var bytes = [], c = 0; c < hex.length; c += 2)
            bytes.push(parseInt(hex.substr(c, 2), 16));
        return bytes;
    }
    function bytesToHex(bytes) {
        for (var hex = [], i = 0; i < bytes.length; i++) {
            hex.push((bytes[i] >>> 4).toString(16));
            hex.push((bytes[i] & 0xF).toString(16));
        }
        return hex.join("");
    }
    function b64tohex(str) {
        for (var i = 0, bin = atob(str.replace(/[ \r\n]+$/, "")), hex = []; i < bin.length; ++i) {
            var tmp = bin.charCodeAt(i).toString(16);
            if (tmp.length === 1) tmp = "0" + tmp;
            hex[hex.length] = tmp;
        }
        return hex.join("");
    }
    function addPreZero(num,length){
        var t = (num+'').length,
        s = '';
        for(var i=0; i<length-t; i++){
        s += '0';
    }
  
 return s+num;
}

在这里一次性补全了，当时找了好多地方才把引入的方法补全。。。