c语言程序设计文件加密解密

#include<stdio.h>

#include<string.h>

#include<stdlib.h>

main()

{

void sc(char *fp,char *key,int Flen,int Klen)

FILE *fp

char *pBuf,filename[20],key[20],ch

printf("请输入选择：A、加密B、解密 C退出\n")

ch=getchar()

while(ch!='c'&&ch!='C')

{

if(ch=='a'||ch=='A'||ch=='b'||ch=='B')

{

printf("请输入要打开的文件名：\n")

scanf("%s",filename)

if((fp=fopen(filename,"rb"))==NULL)

{printf("无法打开文件，请注意尺唤输入后缀！\n")<br/> exit(0)<br/> }

fseek(fp,0,SEEK_END)

int len=ftell(fp)

pBuf=new char[len+1]

rewind(fp)

fread(pBuf,1,len,fp)

pBuf[len]=0

printf("%s\n",pBuf)

fclose(fp)

printf("请输入加密/解密的密码：\n")

scanf("%s",key)

sc(pBuf,key,len,strlen(key))

printf("请输入保存加密文件的文件名：\n")

scanf("%s",filename)

if((fp=fopen(filename,"wb"))==NULL)

{printf("无法保存文件，请注意磁盘是否已满！\n"陵物凯)<br/蚂带> exit(0)<br/> }

else

fwrite(pBuf,1,len,fp)

fclose(fp)

printf("请输入选择：A、加密B、解密 C退出\n")

}

else {

printf("输入错误，请重新输入\n")

}

ch=getchar()

ch=getchar()

}

}

void sc(char *fp,char *key,int Flen,int Klen)

{int i,j,k<br/>for(i=0i<Fleni+=Klen)<br/>for(j=i,k=0k<Klenj++,k++)<br/>fp[j]^=key[k]<br/><br/>fp[i]='\0'<br/>printf("%s\n",fp)<br/>}

C语言设计一个简单的加密解密程序如下：

加密程序代码：

#include<stdio.h>

main()

{

char

c,filename[20]

FILE

*fp1,*fp2

printf("请输入待加密的文件名:\n")

scanf("%s",filename)

fp1=fopen(filename,"r")

fp2=fopen("miwen.txt","w")

do

{

c=fgetc(fp1)

if(c>=32&&c<=126)

{

c=c-32

c=126-c

}

if(c!=-1)

fprintf(fp2,"%c",c)

}

while(c!=-1)

}

解密程序代码：

#include<stdio.h>

#include<string.h>

main()

{

char

c,filename[20]

char

yanzhengma[20]

FILE

*fp1,*fp2

printf("请输入待解密文件名:\n")

scanf("%s",filename)

printf("请输入验证码:\n")

scanf("%s",yanzhengma)

if(strcmp(yanzhengma,"shan")==0)

{

fp1=fopen(filename,"r")

fp2=fopen("yuanwen.txt","w")

do

{

c=fgetc(fp1)

if(c>=32&&c<=126)

{

c=126-c

c=32+c

}

if(c!=-1)

fprintf(fp2,"%c",c)

}

while(c!=-1)

}

else

{

printf("验证码错误！请重新输入:\n")

scanf("%s",filename)

}

}

直接对字符串按字符加减密钥的位数就可以了。

#include

<iostream.h>困族衡

#define

MAX

1000

//加密

char

*

Encryption(char

*E,int

Key)

{

for(int

i=0*(E+i)i++)

{

*(E+i)

+=

Key

if(*(E+i)>'z'穗握)

*(E+i)

-=

('z'-'a')+1

}

return

E

}

//解密

char

*

Decryption(char

*E,int

Key)

{

for(int

i=0*(E+i)i++)

{

*(E+i)

-=

Key

if(*(E+i)<'a')

*(E+i)

+=

('z'-'a')+1

}

return

E

}

void

main()

{

char

a[MAX]

int

key

cout<<"输入字符串:"<<endl

cin

>>

a

cout<<"输入汪做密钥:"<<endl

cin

>>key

cout<<"加密输出:"<<Encryption(a,key)<<endl

cout<<"解密输出:"<<Decryption(a,key)<<endl

}

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