信息计算2019级1班30号刘毅扬

刘毅扬 · 发表于 2022-5-3 22:49:17

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
namespace RSA
{
class RSATools
{
public static bool isPrim(long num)
//以6为步进单元判断其是否为素数
{
//两个较小数另外处理
if (num == 2 || num == 3)
return true;
//不在6的倍数两侧的一定不是质数
if (num % 6 != 1 && num % 6 != 5)
return false;
long tmp = (long)Math.Sqrt(num);
//在6的倍数两侧的也可能不是质数
for (long i = 5; i <= tmp; i += 6)
if (num % i == 0 || num % (i + 2) == 0)
return false;
//排除所有，剩余的是质数
return true;
}
public static long gcd(long x, long y) => y != 0 ? gcd(y, x % y) : x;
//采用递归的形式，判断两个数是否互质
public static long inverse(long number1, long number3)
//利用欧几里得算法计算m，d的逆元
{
long x1 = 1, x2 = 0, x3 = number3, y1 = 0, y2 = 1, y3 = number1;
long q;
long number4 = 0;
long t1, t2, t3;
while (y3 != 0)
{
if (y3 == 1)
{
number4 = y2;
break;
}
else
{
q = (x3 / y3);
t1 = x1 - q * y1;
t2 = x2 - q * y2;
t3 = x3 - q * y3;
x1 = y1; x2 = y2; x3 = y3;
y1 = t1; y2 = t2; y3 = t3;
}
}
if (number4 < 0)
number4 = number4 + number3;
return number4;
}
public static long getMod(long a, long b, long c)
//利用快速指数模运算，计算m^e mod n
{
//指数 e --> a 底数 m --> b 模数 n --> c
long number3 = 1;
while (a != 0)
{
if (a % 2 == 1)
{
a = a - 1;
number3 = (number3 * b) % c;
}
else
{
a = (a / 2);
b = (b * b) % c;
}
}
return number3;
}
public static long getN(long p, long q) => p * q;
public static long getEuler_N(long p, long q) => (p - 1) * (q - 1);
//求N的欧拉函数
public static void getP_Q(out long p, out long q)
{
Random random = new Random();
while (true)
{
p = random.Next(1000);
q = random.Next(2000);
if (isPrim(p) && isPrim(q)) return;
}
}
public static byte[] longToBytes(long a)
{
byte[] b = new byte[8];
b[0] = (byte)(a);
b[1] = (byte)(a >> 8 & 0xFF);
b[2] = (byte)(a >> 16 & 0xFF);
b[3] = (byte)(a >> 24 & 0xFF);
b[4] = (byte)(a >> 32 & 0xFF);
b[5] = (byte)(a >> 40 & 0xFF);
b[6] = (byte)(a >> 48 & 0xFF);
b[7] = (byte)(a >> 56 & 0xFF);
return b;
}
public static long BytesToLong(byte[] input)
{
uint num = (uint)(((input[0] | (input[1] << 8)) | (input[2] << 0x10)) | (input[3] << 0x18));
uint num2 = (uint)(((input[4] | (input[5] << 8)) | (input[6] << 0x10)) | (input[7] << 0x18));
return (long)((num2 << 0x20) | num);
}
public static long[] UTF8ToLong(string input)
{
string input_64 = Convert.ToBase64String(Encoding.UTF8.GetBytes(input));
byte[] inputByte = Convert.FromBase64String(input_64);
long[] inputLong = new long[inputByte.Length];
for (int i = 0; i < inputByte.Length; i++)
{
inputLong[i] = (long)inputByte[i];
}
return inputLong;
}
public static string longToUTF8(long[] input)
{
byte[] inputByte = new byte[input.Length];
for (int i = 0; i < inputByte.Length; i++)
{
inputByte[i] = (byte)input[i];
}
string inputBase64 = Convert.ToBase64String(inputByte);
byte[] outputb = Convert.FromBase64String(inputBase64);
string output = Encoding.UTF8.GetString(outputb);
return output;
}
public static long[] Base64ToLong(string input)
{
List<long> output_l = new List<long>();
string t = "";
for (int i = 0; i < input.Length; i++)
{
t += input[i];
if (input[i] == '=')
{
byte[] tByte = Convert.FromBase64String(t);
output_l.Add(BytesToLong(tByte));
t = "";
}
}
return output_l.ToArray(); ;
}
public static string longToBase64(long[] input)
{
byte[][] inputByte = new byte[input.Length][];
string output = "";
for (int i = 0; i < input.Length; i++)
{
inputByte[i] = longToBytes(input[i]);
output += Convert.ToBase64String(inputByte[i]);
}
return output;
}
}
}
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2.RSA.cs
using System;
using System.Collections.Generic;
using System.Text;
namespace RSA
{
class RSA
{
private long p, q;
private long n;
private long euler_N;
private long[] publicKey;//0-e 1-n
private long[] privateKey;//0-d 1-n
public long P { get => p; set => p = value; }
public long Q { get => q; set => q = value; }
public long[] PublicKey { get => publicKey; set => publicKey = value; }
public long[] PrivateKey { get => privateKey; set => privateKey = value; }
public long N { get => n; set => n = value; }
public long Euler_N { get => euler_N; set => euler_N = value; }
public void InitPublicKey()
//初始化公钥
{
RSATools.getP_Q(out p, out q);
euler_N = RSATools.getEuler_N(p, q);
long e;
n = RSATools.getN(p, q);
Random radom = new Random();
while (true)
{
e = radom.Next(655300);
if (e > 1 && e < euler_N && RSATools.gcd(e, euler_N) == 1 && RSATools.isPrim(e)) break;
}
publicKey = new long[2];
publicKey[0] = e;
publicKey[1] = n;
}
public void InitPrivateKey()
//初始化私钥
{
long d = RSATools.inverse(publicKey[0], euler_N);
privateKey = new long[2];
privateKey[0] = d;
privateKey[1] = n;
}
//加密操作
public long encrypt(long plaintext, long[] p_k) => RSATools.getMod(p_k[0], plaintext, p_k[1]);
//解密操作
public long decrypt(long ciphertext) => RSATools.getMod(privateKey[0], ciphertext, privateKey[1]);
public string getCiphertext(string plaintext, long[] p_k)
//加密明文得到密文
{
long[] p_long = RSATools.UTF8ToLong(plaintext);
long[] c_long = new long[p_long.Length];
for (int i = 0; i < p_long.Length; i++)
{
c_long[i] = encrypt(p_long[i], p_k);
}
string c_text = RSATools.longToBase64(c_long);
return c_text;
}
public string getPlaintext(string ciphertext)
//解密密文得到明文
{
long[] c_long = RSATools.Base64ToLong(ciphertext);
long[] p_long = new long[c_long.Length];
for (int i = 0; i < c_long.Length; i++)
{
p_long[i] = decrypt(c_long[i]);
}
string p_text = RSATools.longToUTF8(p_long);
return p_text;
}
}
}

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