RSA 加密 step 目前固定方式只适用1024长度秘钥，替换计算方式，适配多种长度的RSA秘钥

[DavidLei08]

另测试方法
` public static void main(String[] args) throws Exception {
String publicKey = "MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQDaeKDBABBuLvtoL+ykPLdyjX3HWbBgIpbSBOUHK2Z5uCopAuzv5xYXS6Pst/wivAuQ1U3Zbnxkz8Eecgm81hpBAaKc9dMAxymxqYG1Yv8s2GmKH4SzL0ID52lylT/RbMvabe6JSQ2C0Bc+WNG3nCMn771cY93ZcsJY4LT1rOgiKwIDAQAB";
String privateKey = "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";
String content = "小米";
//公钥加密数据

    String result = Base64Util.encode(RSAUtil.encrypt(content.getBytes(),publicKey));
    System.out.println(result);
    //私钥解密码数据
    String o = new String(RSAUtil.decrypt(Base64Util.decode(result),privateKey));
    System.out.println(o);
}`