0x00 前言 正文开始之前先闲扯几句吧,玩CTF的小伙伴也许会遇到类似这样的问题:表哥,你知道这是什么加密吗?其实CTF中脑洞密码题(非现代加密方式)一般都是各种古典密码的变形,一般出题者会对密文进行一些处理,但是会给留一些线索,所以写此文的目的是想给小伙伴做题时给一些参考,当然常在CTF里出现的编码也可以了解一下.本来是想尽快写出参考的文章,无奈期间被各种事情耽搁导致文章断断续续写了2个月,文章肯定有许多没有提及到,欢迎小伙伴补充,总之,希望对小伙伴们有帮助吧! 0x01 目录 1 2 3…

加密代码 /**解密 * @param content 待解密内容 * @param password 解密密钥 * @return */ public static byte[] decrypt(byte[] content, String password) { try { KeyGenerator kgen = KeyGenerator.getInstance("AES"); kgen.init(128, new SecureRandom(password.getBytes())…

链接:http://poj.org/problem?id=1026 Cipher Time Limit: 1000MS   Memory Limit: 10000K Total Submissions: 21436   Accepted: 5891 Description Bob and Alice started to use a brand-new encoding scheme. Surprisingly it is not a Public Key Cryptosystem, but t…

1031: [JSOI2007]字符加密Cipher Time Limit: 10 Sec  Memory Limit: 162 MBSubmit: 6014  Solved: 2503[Submit][Status][Discuss] Description 喜欢钻研问题的JS同学,最近又迷上了对加密方法的思考.一天,他突然想出了一种他认为是终极的加密办法 :把需要加密的信息排成一圈,显然,它们有很多种不同的读法.例如下图,可以读作: JSOI07 SOI07J OI07JS I07JSO 0…

让上帝的归上帝,凯撒的归凯撒. 下面我们来介绍风靡全球的凯撒密码Caesar cipher,又叫移位密码. 移位密码也就是密码中的字母会按照指定的数量来做移位. 一个常见的案例就是ROT13密码,字母会移位13个位置.由'A' ↔ 'N', 'B' ↔ 'O',以此类推. 写一个ROT13函数,实现输入加密字符串,输出解密字符串. 所有的字母都是大写,不要转化任何非字母形式的字符(例如:空格,标点符号),遇到这些特殊字符,跳过它们. /*思路 26个字母的unicode码在65(A)与90(Z)…

// the parent constructor function Parent(name) { this.name = name || 'Adam'; } // adding functionality to the prototype Parent.prototype.say = function () { return this.name; }; // empty child constructor function Child(name) {} inherit(Child, Paren…

Cipher Message Time Limit:1000MS     Memory Limit:65536KB     64bit IO Format:%I64d & %I64u Description Müller tried to catch Stierlitz red-handed many times, but always failed because Stierlitz could ever find some excuse. Once Stierlitz was looking…

Ancient Roman empire had a strong government system with various departments, including a secret service department. Important documents were sent between provinces and the capital in encrypted form to prevent eavesdropping. The most popular ciphers…

1031: [JSOI2007]字符加密Cipher Time Limit: 10 Sec  Memory Limit: 162 MBSubmit: 5504  Solved: 2277[Submit][Status][Discuss] Description 喜欢钻研问题的JS同学,最近又迷上了对加密方法的思考.一天,他突然想出了一种他认为是终极的加密办法 :把需要加密的信息排成一圈,显然,它们有很多种不同的读法.例如下图,可以读作: JSOI07 SOI07J OI07JS I07JSO 0…

Ancient Roman empire had a strong government system with various departments, including a secret service department. Important documents were sent between provinces and the capital in encrypted form to prevent eavesdropping. The most popular ciphers…