四种加密解密算法的源代码移位密码仿射密码.docVIP

四种加密解密算法的源代码：移位密码、仿射密码、维吉尼亚密码以及置换密码 #include stdio.h #include conio.h #include string.h #include malloc.h void Shift() /*移位密码*/ { char c[100]; int length, i=0, key=0; clrscr(); printf(********Shift Cipher********\nPlease input primal sentence: ); gets(c); length = strlen(c); printf(Input the key(0~26): ); scanf(%d, key); getchar(); if(key0) { printf(The value of key is error!\nPress any key to return...); getch(); return; } for(i=0; ilength; i++) { if(c[i]96c[i]123) c[i] = (c[i]+key-97)%26+65; else if(c[i]64c[i]91) c[i] = (c[i]+key-65)%26+65; } printf(Result is: %s\n, c); for(i=0; ilength; i++) { if(c[i]64c[i]91) c[i] = (c[i]-key-65+26)%26+97; } printf(\nAfter translated the sentence,we can see the primal sentence as follow:\n%s\n, c); printf(Press any key to return...); getch(); } int gcd(int a, int b) /*辗转相除法求a,b的最大公因数*/ { int k = 0; do { k = a%b; a = b; b = k; }while(k!=0); return a; } int Ni(int a, int b) /*求a相对于b的逆*/ { int i = 0; while(a*(++i)%b!=1); return i; } void Affine() /*仿射密码*/ { char c[100]; int length, i=0, ka=0, kb=0, tmp; clrscr(); printf(********Affine Cipher********\nPlease input primal sentence: ); gets(c); length = strlen(c); printf(Input the key(2 numbers): ); scanf(%d%d, ka, kb); getchar(); if(gcd(ka,26)!=1) { printf(The value of the key is error!\nPress any key to return...); return; } for(i=0; ilength; i++) { if(c[i]96c[i]123) c[i] = (ka*(c[i]-97)+kb)%26+65; else if(c[i]64c[i]91) c[i] = (ka*(c[i]-65)+kb)%26+65; } printf(Result is: %s\n, c); for(i=0; ilength; i++) { if(c[i]64c[i]91) { tmp = Ni(ka,26)*((c[i]-65)-kb); if(tmp0) c[i] = tmp%26+26+97; else c[i] = tmp%26+97; } } printf(\nAfter translated the sentence,we can see the primal sentence as follow:\n%s\n, c); printf(Press any key to return...); getch(); } void Vigenere() /*维吉利亚密码*/ { char c[100], key[100]; int lenc, lenk, i=0, j=0, tmp; clrscr(); printf(********Vigenere Cipher********\nPlease