nodeJS rsasha加密

/**
 * Created by Administrator on 2017/4/19.
 */
var crypto = require('crypto');

//签名
function signer(algorithm, key, data) {
    key = get_key(key, 1);
    var sign = crypto.createSign(algorithm);
    sign.update(data);
    sig = sign.sign(key, 'base64');
    return sig;
}

//验证签名
function verify(algorithm, pubkey, sig, data) {
    pubkey = get_key(pubkey, 0);
    var verify = crypto.createVerify(algorithm);
    verify.update(new Buffer(data, 'utf-8'));
    return verify.verify(pubkey, sig, 'base64');
}

/**
*获取PEM格式的秘钥（公钥，私钥）
*key：待编码的key
*keyType: 0 公钥 1 私钥
*/
function get_key(key,keyType) {
    key = insert_str(key, '
', 64);
    switch (keyType) {
        case 0:
            key = '-----BEGIN PUBLIC KEY-----
' + key + '-----END PUBLIC KEY-----';
            break;
        case 1:
            key = '-----BEGIN PRIVATE KEY-----
' + key + '-----END PRIVATE KEY-----';
            break;
    }
    return key;
}

/**
 * 在指定位置插入字符串
 * @待插入字符串 str
 * @插入字符串 insert_str
 * @位置 sn
 * @returns {string}
 */
function insert_str(str, insert_str, sn) {
    var newstr = "";
    for (var i = 0; i < str.length; i += sn) {
        var tmp = str.substring(i, i + sn);
        newstr += tmp + insert_str;
    }
    return newstr;
}

/**
 * RSA-SHA1验证签名
 * @数据 {string} data
 * @公钥 {string} pubkey
 * @签名 {string} sig
 */
exports.rsasha1verify = function(data,pubkey,sig){
    var algorithm = 'RSA-SHA1';
    return verify(algorithm,pubkey,sig,data);
}

/**
 * RSA-SHA1签名
 * @加密私钥 {string} key
 * @数据 {string} data
 */
exports.rsasha1sign = function (key,data) {
    var algorithm = 'RSA-SHA1';
    return signer(algorithm, key, data);
}

/**
 * RSA-SHA256签名
 * @加密私钥 {string} key
 * @数据 {string} data
 */
exports.rsasha256sign = function (key ,data) {
    var algorithm = 'RSA-SHA256';
    return signer(algorithm, key, data);
}

/**
 * RSA-SHA256验证签名
 * @数据 {string} data
 * @公钥 {string} pubkey
 * @签名 {string} sig
 */
exports.rsasha256verify = function (data, pubkey, sig) {
    var algorithm = 'RSA-SHA256';
    return verify(algorithm, pubkey, sig, data);
}