RC4流密碼算法之C語言實現(xiàn)

1、RC4流密碼算法之C語言實現(xiàn)RC4加密算法RC4算法的原理很簡單，包括初始化算法（KSA）和偽隨機子密碼生成算法（PRGA)兩大部分。假設(shè)S-box長度和密鑰長度均為為n。先來看看算法的初始化部分（用類C偽代碼表示）：for (i=0; in; i+)s=i;在初始化的過程中，密鑰的主要功能是將S-box攪亂，i確保S-box的每個元素都得到處理，j保證S-box的攪亂是隨機的。而不同的S-box在經(jīng)過偽隨機子密碼生成算法的處理后可以得到不同的子密鑰序列，并且，該序列是隨機的：j=0;for (i=0; in; i+)j=(j+s+k)%256;swap(s, sj);i=j=0;得到的子密碼

2、sub_k用以和明文進行xor運算，得到密文，解密過程也完全相同。根據(jù)目前的分析結(jié)果，沒有任何的分析對于密鑰長度達到128位的RC4有效，所以，RC4是目前最安全的加密算法之一，大家可以放心使用！while (明文未結(jié)束)+i%=n;j=(j+s)%n;swap(s, sj);sub_k=s(s+sj)%n);位長可以自己隨意設(shè)置，將256設(shè)置為你希望的即可我的C語言源碼：平臺：windowsXP，VC+6.0有什么大家可以討論的地方請留言或發(fā)郵件至我郵箱：#include#include#includevoid swap(unsigned char *s1,unsigned char *s2

3、)char temp;temp=*s1;*s1=*s2;*s2=temp;void re_S(unsigned char *S)unsigned int i;for(i=0;i256;i+) Si=i;void re_T(unsigned char *T,char *key)int i;int keylen;keylen=strlen(key);for(i=0;i256;i+) Ti=keyi%keylen;void re_Sbox(unsigned char *S,unsigned char *T)int i;int j=0;for(i=0;i256;i+) j=(j+Si+Ti)%256;

4、 swap(&Si,&Sj);void re_RC4(unsigned char *S,char *key)char T255=0;re_S(S);re_T(T,key);re_Sbox(S,T);void RC4(FILE *readfile,FILE *writefile,char *key) unsigned char S255=0;unsigned char readbuf1;int i,j,t; re_RC4(S,key);i=j=0;while(fread(readbuf,1,1,readfile) i = (i + 1) % 256; j = (j + Si) % 256; sw

5、ap(&Si,&Sj); t = (Si + (Sj % 256) % 256; readbuf0=readbuf0St; fwrite(readbuf,1,1,writefile); memset(readbuf,0,1);printf(加密|解密成功!n);int main(int argc,char *argv)char *Filename1,*Filename2;char *key;FILE *file1,*file2;Filename1 = argv1;Filename2 = argv2;key=argv3;if ( argc = 4) printf(*正在加密中*n);else p

6、rintf(輸入格式： n); printf(文件名|加密或解密文件名|存放文件名|密鑰 n); return -1; if (file1= fopen(Filename1,rb) = NULL| (file2 = fopen(Filename2,wb)=NULL) printf(Cant open filen); return -1; RC4(file1,file2,key);fclose(file1);fclose(file2);return 0;加密解密算法 RC5- -#include #include math.h#include static const w=32;static c

7、onst r=12;static const b=16;static const t=26;/2*r+2=12*2+2static const c=4; /r*8/b = 16*8/32 typedef unsigned long int FOURBYTEINT;typedef unsigned char BYTE;/* 循環(huán)左移和右移函數(shù)* x : 被循環(huán)的數(shù)* y : 將要循環(huán)的位數(shù)*/#define ROTL(x,y) (x)(w-(y&(w-1)#define ROTR(x,y) (x)(y&(w-1) | (x)(w-(y&(w-1)/* 產(chǎn)生子密鑰的函數(shù)*/void generat

8、eChildKey(unsigned char*,FOURBYTEINT*);/* 產(chǎn)生初試密鑰的函數(shù)*/void InitialKey(unsigned char* KeyK,int b)for(int i=0;ib;i+) KeyKi=0;int intiSeed=3;KeyK0=intiSeed;for(i=1;ib;i+) KeyKi = (BYTE) ( (int)(pow(3,i)%(255-i) ); /KeyKi = KeyKi-1*intiSeed % 256;/* 取最近奇數(shù)的函數(shù)*/int Odd(double fl)int floorOffl = (int)floor(

9、fl);if (floorOffl% 2=0) return floorOffl+1;return floorOffl;/* 加密函數(shù)*/void Encipher(FOURBYTEINT* In,FOURBYTEINT* Out,FOURBYTEINT* S)FOURBYTEINT X,Y;X = In0+S0;Y = In1+S1;for(int i=1;i0;i-) Y = ROTR(Y-S2*i+1,X)X; X = ROTR(X-S2*i,Y)Y; Out0=X - S0;Out1=Y - S1;/* 主函數(shù)*/void main() FOURBYTEINT ChildKeyS2*r

10、+2; /64bitunsigned char KeyKb;/8bit=byteInitialKey(KeyK,b);int k;generateChildKey(KeyK,ChildKeyS);FOURBYTEINT Source2=8888,6666;/coutSource0 Source1endl;printf(加密以前的明文:);for (k=0;k2;k+) printf(%.8lX ,Sourcek);FOURBYTEINT Dest2;Encipher(Source,Dest,ChildKeyS);/coutDest0 Dest1endl;printf(n);printf(加密以

11、后的密文:);for (k=0;k2;k+) printf(%.8lX ,Destk);printf(n);Decipher(Dest,Source,ChildKeyS);/coutSource0 Source1endl;printf(解密以后的明文:);for (k=0;k2;k+) printf(%.8lX ,Sourcek);printf(n);/*printf(加密以前的明文:);for (k=0;k6;k+) printf(%.8lX ,mingwen_orgk);printf(n);printf(加密以后的密文:);for (k=0;k6;k+) printf(%.8lX ,miw

12、enk);printf(n);printf(解密以后的明文:);for (k=0;k6;k+) printf(%.8lX ,mingwen_finalk);printf(n);*/void generateChildKey(unsigned char* KeyK,FOURBYTEINT* ChildKeyS)const double e = 2.9;const double Phia = 1.9;/int PW = Odd(e-1)*pow(2,w);int PW = 0xb7e15163;/int QW = Odd(Phia -1)*pow(2,w);int QW = 0x9e3779b9;int i;FOURBYTEINT Lc;/初試化數(shù)組 SChildKeyS0=PW;for ( i=1;it;i+) ChildKeySi=(ChildKeySi-1+ QW);/% (2w)不需要/transform from K to L/initialization Lfor(i=0;ic;i+) Li=0;int u = w/8;for (i=b-1;i!=-1; i-) Li/u = (Li/u8)+KeyKi;for (i=0;i4;i+)printf(%.8Xn,Li);/generate child k