基于.net 4.0框架的Cipher演示程序

using System.Text;

namespace Cipher.Algorithm
{
    static class Caesar
    {
        static public string Encrypt(string input, int key)
        {
            StringBuilder sb = new StringBuilder();
            for(int i = 0; i < input.Length; ++i)
            {
                if ('a' <= input[i] && input[i] <= 'z')
                {
                    sb.Append((char)((input[i] - 'a' + key + 26) % 26 + 'a'));
                }
                else if ('A' <= input[i] && input[i] <= 'Z')
                {
                    sb.Append((char)((input[i] - 'A' + key + 26) % 26 + 'A'));
                }
                else
                {
                    sb.Append(input[i]);
                }
            }
            return sb.ToString();
        }

        static public string Decrypt(string input, int key)
        {
            StringBuilder sb = new StringBuilder();
            for (int i = 0; i < input.Length; ++i)
            {
                if ('a' <= input[i] && input[i] <= 'z')
                {
                    sb.Append((char)((input[i] - 'a' - key + 26) % 26 + 'a'));
                }
                else if ('A' <= input[i] && input[i] <= 'Z')
                {
                    sb.Append((char)((input[i] - 'A' - key + 26) % 26 + 'A'));
                }
                else
                {
                    sb.Append(input[i]);
                }
            }
            return sb.ToString();
        }
    }
}

using System;
using System.Text;

namespace Cipher.Algorithm
{
    public class Hill
    {
        //  矩阵阶数
        private int _level;
        //  加密矩阵
        private long[][] _matrix;
        //  解密矩阵
        private long[][] _inverseMatrix = null;
        
        private int _times = 0;

        //  用于填充的无效字符
        const char INVALID_CHAR = 'A';

        /// <summary>
        /// 带阶数的构造函数
        /// </summary>
        /// <param name="level">矩阵阶数</param>
        public Hill(int level)
        {
            _level = level;
            while(_inverseMatrix == null)
            {
                _matrix = getRandomMatrix();
                _inverseMatrix = getInverseMatrix(_matrix);
                ++_times;
            }
            ;
        }

        public Hill(int level, long[][] matrix)
        {
            _level = level;
            _matrix = matrix;
            _inverseMatrix = getInverseMatrix(_matrix);
            if (null == _inverseMatrix) _inverseMatrix = getNewMatrix();
        }

        #region Properties
        

        public int Level
        {
            get
            {
                return _level;
            }
        }

        /// <summary>当前矩阵
        /// </summary>
        public long[][] Matrix
        {
            get
            {
                return _matrix;
            }
        }

        public long[][] InverseMatrix
        {
            get
            {
                return _inverseMatrix;
            }
        }

        public int Times
        {
            get
            {
                return _times;
            }
        }
        #endregion

        /// <summary>
        /// 得到一个新的整数矩阵
        /// </summary>
        /// <returns>矩阵</returns>
        public long[][] getNewMatrix()
        {
            long[][] res = new long[_level][];
            for (int i = 0; i < _level; ++i) res[i] = new long[_level];
            for (int i = 0; i < _level; ++i)
                for (int j = 0; j < _level; ++j) res[i][j] = 0;
            return res;
        }

        /// <summary>
        /// 得到一个n阶整数矩阵
        /// </summary>
        /// <param name="level">阶数</param>
        /// <returns>矩阵</returns>
        public static long[][] getNewMatrix(int level)
        {
            long[][] res = new long[level][];
            for (int i = 0; i < level; ++i) res[i] = new long[level];
            for (int i = 0; i < level; ++i)
                for (int j = 0; j < level; ++j) res[i][j] = 0;
            return res;
        }
        
        /// <summary>
        /// 求关于MOD26的逆矩阵
        /// </summary>
        /// <param name="o">原矩阵</param>
        /// <returns>逆矩阵</returns>
        private long[][] getInverseMatrix(long[][] o)
        {
            long[][] res = getNewMatrix();
            long[][] original = getNewMatrix();

            for (int i = 0; i < _level; ++i)
            {
                for (int j = 0; j < _level; ++j)
                {
                    if (i == j) res[i][j] = 1;
                    else res[i][j] = 0;
                    original[i][j] = o[i][j];
                }
            }
            for (int k = 0; k <_level; ++k)
            {
                bool isGCD = false;
                for (int i = k; i < _level; ++i)
                {
                    if (GCD(original[i][k], 26) == 1)
                    {
                        isGCD = true;
                        if (i != k)
                        {
                            long[] temp1 = original[i], temp2 = res[i];
                            original[i] = original[k]; res[i] = res[k];
                            original[k] = temp1; res[k] = temp2;
                        }
                        break;
                    }
                }
                //  若矩阵一列中没有与26互素的元素，则认为该矩阵不可逆
                if (!isGCD) return null;
                long ie = getInverseElement(original[k][k], 26);
                Console.WriteLine(original[k][k] + "的逆元是：" + ie);
                if (-1 == ie) return null;
                for (int j = 0; j < _level; ++j)
                {
                    original[k][j] = (original[k][j] * ie) % 26;
                    res[k][j] = (res[k][j] * ie) % 26;
                }
                for (int i = k + 1; i < _level; ++i)
                {
                    long l = original[i][k] / original[k][k];
                    for (int j = 0; j < _level; ++j)
                    {
                        //  对增广矩阵的运算
                        res[i][j] = getMOD((res[i][j] - l * res[k][j]), 26);
                        //  对原矩阵的运算
                        original[i][j] = getMOD((original[i][j] - l * original[k][j]), 26);
                    }
                }
            }
            for (int k = _level - 1; k > 0; --k)
            {
                if (original[k][k] == 0) return null;
                for (int i = k - 1; i >= 0; --i)
                {
                    long l = original[i][k] / original[k][k];

                    //  对增广矩阵的运算
                    for (int j = 0; j < _level; ++j)
                    {
                        if (res[k][j] == 0) continue;
                        res[i][j] = getMOD((res[i][j] - l * res[k][j]), 26);
                    }
                    //  对原矩阵的运算
                    original[i][k] = getMOD((original[i][k] - l * original[k][k]), 26);
                }
            }
            return res;
        }

        private long getMOD(long x, long m)
        {
            while (x < m)
            {
                x += m;
            }
            return x % m;
        }

        /// <summary>
        /// 求a关于m的乘法逆元
        /// </summary>
        /// <param name="a"></param>
        /// <param name="m"></param>
        /// <returns>逆元</returns>
        public static long getInverseElement(long a, long m)
        {
            long x = 0, y = 0;
            long gcd = E_GCD(a, m, ref x, ref y);
            if (1 % gcd != 0) return -1;
            x *= 1 / gcd;
            m = Math.Abs(m);
            long res = x % m;
            if (res <= 0) res += m;
            return res;
        }

        /// <summary>
        /// 拓展欧几里德算法
        /// </summary>
        /// <param name="a"></param>
        /// <param name="b"></param>
        /// <param name="x"></param>
        /// <param name="y"></param>
        /// <returns>GCD（a， b）</returns>
        public static long E_GCD(long a, long b, ref long x, ref long y)
        {
            if (0 == b)
            {
                x = 1;
                y = 0;
                return a;
            }
            long res = E_GCD(b, a % b, ref x, ref y);
            long temp = x;
            x = y;
            y = temp - a / b * y;
            return res;
        }

        /// <summary>
        /// 求最大公约数
        /// </summary>
        /// <param name="x">第一个参数</param>
        /// <param name="y">第二个参数</param>
        /// <returns>最大公约数</returns>
        static public long GCD(long x, long y)
        {
            if (y == 0) return x;
            return GCD(y, x % y);
        }

        static int GetRandomSeed()
        {
            byte[] bytes = new byte[4];
            System.Security.Cryptography.RNGCryptoServiceProvider rng = new System.Security.Cryptography.RNGCryptoServiceProvider();
            rng.GetBytes(bytes);
            return BitConverter.ToInt32(bytes, 0);
        }

        private long[][] getRandomMatrix()
        {
            long[][] res = getNewMatrix();

            for (int i = 0; i < _level; ++i)
            {
                for (int j = 0; j < _level; ++j)
                {
                    int t;
                    Random rd = new Random(GetRandomSeed());
                    t = rd.Next(0, 26);
                    res[i][j] = t;
                }
            }
            return res;
        }

        private string getOneGroup(string input, long[][] matrix)
        {
            StringBuilder sb = new StringBuilder();
            int[] p = new int[_level];
            for (int i = 0; i < _level; ++i)
            {
                if (i < input.Length)
                    p[i] = input[i] - 'A';
                else p[i] = INVALID_CHAR;
            }
            for (int i = 0; i < _level; ++i)
            {
                long o = 0;
                for (int j = 0; j < _level; ++j)
                {
                    o += matrix[i][j] * p[j] ;
                }
                Console.Write(o.ToString() + " ");
                sb.Append((char)(o % 26 + 'A'));
            }
            Console.WriteLine();
            return sb.ToString();
        }

        /// <summary>
        /// 加密
        /// </summary>
        /// <param name="input">请确保输入的字符串只有字母</param>
        /// <returns></returns>
        public string Encrypt(string input)
        {
            StringBuilder sb = new StringBuilder();
            input = input.ToUpper();
            for (int i = 0; i < input.Length; i += _level)
            {
                int end = _level < (input.Length - i) ? _level : (input.Length - i);
                sb.Append(getOneGroup(input.Substring(i, end), _matrix));
            }
            return sb.ToString();
        }

        public string Decrypt(string input)
        {
            StringBuilder sb = new StringBuilder();
            input = input.ToUpper();
            for (int i = 0; i < input.Length; i += _level)
            {
                int end = _level < (input.Length - i) ? _level : (input.Length - i);
                sb.Append(getOneGroup(input.Substring(i, end), _inverseMatrix));
            }
            return sb.ToString();
        }
    }
}

using System.Text;
using System.Windows;

namespace Cipher.Algorithm
{
    public static class Playfair
    {
        private static char[,] _key = new char[5, 5];     //  经过处理的5×5矩阵
        private static Point[] _location = new Point[26]; //  26个字母在key中的位置
        private static string _group;   //  分组后的字符串
        private static char _ch = 'Q';    //  无效字母，如Q， K， X

        public static string Encrypt(string input)
        {
            StringBuilder sb = new StringBuilder();
            string str = group(input);
            for(int i = 0; i < str.Length; i += 2)
            {
                int r1 = (int)(_location[str[i] - 'A'].X);
                int r2 = (int)(_location[str[i + 1] - 'A'].X);
                int c1 = (int)(_location[str[i] - 'A'].Y);
                int c2 = (int)(_location[str[i + 1] - 'A'].Y);
                //  字母同行
                if (r1 == r2)
                {
                    sb.Append(_key[r1, (c1 + 1) % 5]).Append(_key[r1, (c2 + 1) % 5]);
                }
                //  字母同列
                else if (c1 == c2)
                {
                    sb.Append(_key[(r1 + 1) % 5, c1]).Append(_key[(r2 + 1) % 5, c1]);
                }
                else
                {
                    if (r1 > r2 && c1 > c2)
                    {
                        sb.Append(_key[r1, c2]).Append(_key[r2, c1]);
                    }
                    else if (r1 < r2 && c1 > c2)
                    {
                        sb.Append(_key[r2, c1]).Append(_key[r1, c2]);
                    }
                    else if (r1 > r2 && c1 < c2)
                    {
                        sb.Append(_key[r1, c2]).Append(_key[r2, c1]);
                    }
                    else
                    {
                        sb.Append(_key[r2, c1]).Append(_key[r1, c2]);
                    }
                }
            }
            return sb.ToString();
        }

        public static string Decrypt(string input)
        {
            StringBuilder sb = new StringBuilder();
            string str = (string)input.ToUpper();
            if (str.Length % 2 == 1 || str.Length == 0 || str.IndexOf(' ') != -1) return "";
            for (int i = 0; i < str.Length; i += 2)
            {
                int r1 = (int)(_location[str[i] - 'A'].X);
                int r2 = (int)(_location[str[i + 1] - 'A'].X);
                int c1 = (int)(_location[str[i] - 'A'].Y);
                int c2 = (int)(_location[str[i + 1] - 'A'].Y);
                //  字母同行
                if (r1 == r2)
                {
                    sb.Append(_key[r1, (c1 - 1 + 5) % 5]).Append(_key[r1, (c2 - 1 + 5) % 5]);
                }
                //  字母同列
                else if (c1 == c2)
                {
                    sb.Append(_key[(r1 - 1 + 5) % 5, c1]).Append(_key[(r2 - 1 + 5) % 5, c1]);
                }
                else
                {
                    if (r1 > r2 && c1 > c2)
                    {
                        sb.Append(_key[r1, c2]).Append(_key[r2, c1]);
                    }
                    else if (r1 < r2 && c1 > c2)
                    {
                        sb.Append(_key[r2, c1]).Append(_key[r1, c2]);
                    }
                    else if (r1 > r2 && c1 < c2)
                    {
                        sb.Append(_key[r1, c2]).Append(_key[r2, c1]);
                    }
                    else
                    {
                        sb.Append(_key[r2, c1]).Append(_key[r1, c2]);
                    }
                }
            }
            for(int i = 2; i < sb.Length; ++i)
            {
                if(sb[i].Equals(sb[i - 2]) && sb[i - 1].Equals(_ch))
                {
                    sb.Remove(i - 1, 1);
                }
            }
            if (sb[sb.Length - 1].Equals(_ch)) sb.Remove(sb.Length - 1, 1);
            return sb.ToString();
        }

        public static char[, ] Key(string word)
        {
            string temp = word.ToUpper();
            StringBuilder sb = new StringBuilder();
            bool[] flag = new bool[26];
                for(int i = 0; i < temp.Length; ++i)
                {
                    //  该字母未出现过
                    if (flag[temp[i] - 'A'] == false)
                    {
                        sb.Append(temp[i]);
                    }
                    flag[temp[i] - 'A'] = true;
                }
                for(int i = 0; i < 26; ++i)
                {
                    if (i == 'J' - 'A')
                    {
                        continue;
                    }
                    if (flag[i] == false)
                    {
                        sb.Append((char)(i + 'A'));
                    }
                }
                for (int i = 0; i < 5; ++i)
                {
                    for(int j = 0; j < 5; ++j)
                    {
                        _key[i, j] = sb[i * 5 + j];
                        Point insert = new Point(i, j);
                        _location[_key[i, j] - 'A'] = insert;
                    }
                }
            return _key;
        }

        private static string group(string input)
        {
            StringBuilder sb = new StringBuilder();
            string temp = input.ToUpper();
            for(int i = 0; i < temp.Length; )
            {
                if (0 != i && sb.Length > 0 && temp[i] == sb[sb.Length - 1])
                {
                    sb.Append(_ch);
                }
                else if ('A' <= temp[i] && temp[i] <= 'Z')
                {
                    sb.Append(temp[i]);
                    ++i;
                }
                else
                {
                    ++i;
                }
            }
            if (sb.Length % 2 == 1)
            {
                sb.Append(_ch);
            }
            _group = sb.ToString();
            return sb.ToString();
        }
    }
}

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace Cipher.Algorithm
{
    class Rd
    {
        public static int GetRandomSeed()
        {
            byte[] bytes = new byte[4];
            System.Security.Cryptography.RNGCryptoServiceProvider rng = new System.Security.Cryptography.RNGCryptoServiceProvider();
            rng.GetBytes(bytes);
            return BitConverter.ToInt32(bytes, 0);
        }
    }
}

using System;
using System.Collections.Generic;
using System.Linq;
using System.Numerics;
using System.Text;

namespace Cipher.Algorithm
{
    class RSA
    {
        //  已保存的素数集
        protected int[] primes = { 307, 311, 313, 317, 331, 337, 347, 349, 353, 359, 367, 373, 379, 383, 389 };

        protected BigInteger rsa_e;
        protected BigInteger rsa_d;
        protected BigInteger rsa_n;

        protected BigInteger rsa_p;
        protected BigInteger rsa_q;

        #region Properties
        public string P
        {
            get
            {
                return rsa_p.ToString();
            }
        }
        public string Q
        {
            get
            {
                return rsa_q.ToString();
            }
        }

        public string E
        {
            get
            {
                return rsa_e.ToString();
            }
        }

        public string D
        {
            get
            {
                return rsa_d.ToString();
            }
        }

        public string N
        {
            get
            {
                return rsa_n.ToString();
            }
        }
        #endregion

        public RSA()
        {
            BigInteger p, q;
            p = getRandomPrime();
            q = getRandomPrime();
            while (p == q)
            {
                //  确保p与q不相等
                q = getRandomPrime();
            }
            BigInteger n = p * q;
            BigInteger fi_n = (p - 1) * (q - 1);
            BigInteger e = getRandomPrime();
            while (GCD(fi_n, e) != 1)
            {
                e = getRandomPrime();
            }
            BigInteger d = getInverseElement(e, fi_n);

            rsa_e = e;
            rsa_d = d;
            rsa_n = n;
            rsa_p = p;
            rsa_q = q;
        }

        public RSA(BigInteger p, BigInteger q, BigInteger e)
        {
            rsa_p = p;
            rsa_q = q;
            rsa_e = e;
            BigInteger n = p * q;
            BigInteger fi_n = (p - 1) * (q - 1);
            if (GCD(fi_n, e) != 1) return;
            BigInteger d = getInverseElement(e, fi_n);

            rsa_d = d;
            rsa_n = n;
        }

        public BigInteger[] Encrypt(string input)
        {
            List<BigInteger> res = new List<BigInteger>();
            char[] c = input.ToArray();
            for (int i = 0; i < c.Length; ++i)
            {
                res.Add(EncryptSingle(c[i], rsa_e));
            }
            return res.ToArray();
        }

        public char[] Decrypt(BigInteger[] input)
        {
            List<char> res = new List<char>();
            for (int i = 0; i < input.Length; ++i)
            {
                int ch = Int32.Parse(EncryptSingle(input[i], rsa_d).ToString());
                res.Add((char)ch);
            }
            return res.ToArray();
        }

        /// <summary>
        /// 对单个字符进行幂运算加密
        /// </summary>
        /// <param name="input"></param>
        /// <param name="m"></param>
        /// <returns></returns>
        protected BigInteger EncryptSingle(BigInteger input, BigInteger m)
        {
            BigInteger res = 1;
            for (int i = 0; i < m; ++i)
            {
                res = (res * input) % rsa_n;
            }
            return res;
        }

        protected BigInteger getRandomPrime()
        {
            Random rd = new Random(Rd.GetRandomSeed());
            BigInteger res = new BigInteger(primes[rd.Next(0, primes.Length)]);
            return res;
        }

        protected BigInteger GCD(BigInteger a, BigInteger b)
        {
            if (b == BigInteger.Zero) return a;
            return GCD(b, a % b);
        }

        /// <summary>
        /// 求a关于m的乘法逆元
        /// </summary>
        /// <param name="a">原数</param>
        /// <param name="m">被MOD的数</param>
        /// <returns>逆元</returns>
        protected BigInteger getInverseElement(BigInteger a, BigInteger m)
        {
            BigInteger x = 0, y = 0;
            BigInteger gcd = E_GCD(a, m, ref x, ref y);
            if (1 % gcd != 0) return -1;
            x *= 1 / gcd;
            m = BigInteger.Abs(m);
            BigInteger res = x % m;
            if (res <= 0) res += m;
            return res;
        }

        /// <summary>
        /// 拓展欧几里德算法
        /// </summary>
        /// <param name="a"></param>
        /// <param name="b"></param>
        /// <param name="x"></param>
        /// <param name="y"></param>
        /// <returns>GCD（a， b）</returns>
        protected BigInteger E_GCD(BigInteger a, BigInteger b, ref BigInteger x, ref BigInteger y)
        {
            if (0 == b)
            {
                x = 1;
                y = 0;
                return a;
            }
            BigInteger res = E_GCD(b, a % b, ref x, ref y);
            BigInteger temp = x;
            x = y;
            y = temp - a / b * y;
            return res;
        }
    }
}