信息安全的古典加密之替代加密算法和置换加密算法C/C++实现

/* *********************** 置换加密 */ #include <iostream> #include <string> using namespace std; //获取置换序列 void GetSequence(string key,int len,int *a) { // int *a = new int[len]; //数组a存放置换序列 for (int i=0; i<len; ++i) { a[i] = i+1; } //选择排序获取密钥的置换序列 int k = 0; string akey = key; //拷贝一份密钥，进行操作，不改变原密钥 for (int i=0; i<len; ++i) { k = i; for (int j=i+1; j<len; ++j) { if (akey[k] > akey[j]) { k = j; } } if (k != i) { char ch; ch = akey[k]; akey[k] = akey[i]; akey[i] = ch; int temp = 0; temp = a[k]; a[k] = a[i]; a[i] = temp; } } } string cipher(string context,string key,int *a) { string ciphertext = context; int len = key.length(); int row = context.length()/key.length(); // cout<<row<<endl; for (int i=0; i<row; ++i) { for (int j=0; j<len; ++j) { ciphertext[j+i*len] = context[(a[j]-1)+i*len]; } } cout<<ciphertext<<endl; return ciphertext; } string decipher(string ciphertext,string key,int *a) { string context = ciphertext; int len = key.length(); int row = ciphertext.length()/key.length(); // cout<<row<<endl; for (int i=0; i<row; ++i) { for (int j=0; j<len; ++j) { context[(a[j]-1)+i*len] = ciphertext[j+i*len]; } } cout<<context<<endl; return context; } void main() { string key; //密钥 string context; //明文 string ciphertext; //密文 // string app; //需要增补的空格 int len = 0; //密钥的长度 int num = 0; //需要增补的空格的个数 cout<<"请输入密钥"<<endl; getline(cin,key); // cout<<key<<endl; len = key.length(); cout<<"请输入明文"<<endl; getline(cin,context); // cout<<context<<endl; ciphertext = context; num = context.length()%len; if (num != 0) { num = len - num; string app(num,'*'); cout<<app<<endl; context += app; ciphertext = context; } int *a = new int[len]; //存放密钥的序列 GetSequence(key,len,a); ciphertext = cipher(context,key,a); //加密处理 context = decipher(ciphertext,key,a); //解密； }