C中Blowfish加密的适应问题

I'm writing a program that implements the Boneh-Franklin Identity Based Encryption. For the actual encryption methods, I use Blowfish which I got from (https://voltar.org/). I'm trying to adapt the blowfish encryption/decryption code to my program. The difference in my program is that I read the message from the standard input, encrypt it and print the encryption, then decrypt it and print the decryption (which should be the original message). Currently, I read the input message up to a "?" character and then try to follow the code from the site. However, the decryption is printed as unreadable characters. I tried to solve this problem but I got stuck. Can you please help me?

我正在编写一个实现Boneh-Franklin Identity Based Encryption的程序。对于实际的加密方法,我使用的是Blowfish(https://voltar.org/)。我正在尝试将blowfish加密/解密代码改编为我的程序。我的程序的不同之处在于我从标准输入读取消息,加密并打印加密,然后解密并打印解密(应该是原始消息)。目前,我读取输入消息到“?”字符,然后尝试按照网站上的代码。但是,解密被打印为不可读的字符。我试图解决这个问题,但我卡住了。你能帮我么?

//initializations

BF_KEY s_key;       //shared key of the blowfish encryption
char plain[1000000];    //the plaintext of the message
char cipher[1000000];   //the ciphertext of the message  
char byte;          //to hold the byte of the msg
char *token;        //points to tokens of the msg
char IV[8]="MY*IV000";  //the initialization vector
int offset = 0;     //the offset of encryption
int b_count = 0;        //number of bytes in d_buf
char block[8];      //blocks of encryption
char msg[1000000];      //the input msg from the user
int j;          //used to read input in a loop with getchar
int i;          //for-loop value
int len;            //used to calculate lengths different variables
int f;          //flag for the setup stage
int q;    //used to read input in a loop with getchar
q=0;    //reset the index reader
char in;    //to read characters
printf("Please enter the message you wish to send:\n");

************ This is my code to read the input message: ***************

************这是我读取输入消息的代码:***************

//this loop reads the input from the user since C does not 
//provide a safe function to read strings with white spaces

while (in != '?'){   
in=getchar();
if(in != '?')    //dont include the delim character in the string
         msg[q++]=in;
}
msg[q]='\0';    //truncate the string by the null character

************ Then I used the code (cited and referenced) for encryption ***************

************然后我使用代码(引用和引用)进行加密***************

Of course I modified it as message read from stdin not program args

当然我把它修改为从stdin而不是程序args读取的消息

for(i=0; i<strlen(msg); i++)    //copy the input message to plain
    plain[i] = msg[i];

//set up the shared key of the BF encryption

BF_set_key(&s_key, strlen(ekey_buf), ekey_buf);    

while(1){
    for(i=0; i<8; i++)    //reinitiate the block of 8 characters each time

        block[i] = 0;
    strncpy(block, plain+offset, 8);
    BF_cbc_encrypt(plain+offset, cipher, 8, &s_key, IV, BF_ENCRYPT);   
    for(i=0; i<strlen(cipher); i++){
    printf("%02x", (unsigned char) cipher[i]);
}
if( strlen(plain+offset)>8 ){    //if there is still more characters
     offset += 8;         //process the next block of 8 characters
} else
       break;       
}
//the cipher is correctly printed

************ Then I used the code (cited and referenced) for decryption ***************

************然后我使用代码(引用和引用)进行解密***************

Here, I excluded the part where it tokenized the cipher and created the plain char array for decryption, I simply passed the cipher array to be decrypted (as it is output from the encryption function), and stored in the plain char array with length = strlen(cipher)

在这里,我排除了它对密码进行了标记并创建了用于解密的普通字符数组的部分,我只是传递了要解密的密码数组(因为它是从加密函数输出的),并存储在长度为=的纯字符数组中strlen的(加密)

//set up the shared key of the BF encryption

BF_set_key(&s_key, strlen(dkey_buf), dkey_buf);        
BF_cbc_encrypt(cipher, plain, strlen(cipher), &s_key, IV, BF_DECRYPT);  

printf("plain after decryption: %s\n", plain);
//HERE IS THE PROBLEM: I get unreadable characters as output of this line

Any help is appreciated. Sorry for the inconvenience and many thanks in advance.

任何帮助表示赞赏。很抱歉给您带来不便,并提前致谢。

4 个解决方案

#1

I have a hunch it's a dirty IV, but it's just a guess.

我有一个预感,这是一个肮脏的IV,但这只是一个猜测。

for(i=0; i<8; i++) ivec[i] = 'i';
BF_cbc_encrypt(inputz, outputz, strlen(inputz), &key, ivec, BF_ENCRYPT);

// won't decrypt right:
BF_cbc_encrypt(inputz, outputz, strlen(inputz), &key, ivec, BF_DECRYPT);
// without resetting the ivec to all 'i's, the decryption will fail.

// This would work though:

for(i=0; i<8; i++) ivec[i] = 'i';
BF_cbc_encrypt(inputz, outputz, strlen(inputz), &key, ivec, BF_ENCRYPT);

for(i=0; i<8; i++) ivec[i] = 'i';
BF_cbc_encrypt(inputz, outputz, strlen(inputz), &key, ivec, BF_DECRYPT);

My guess is only correct if every block after the first decrypts correctly though.

我的猜测只有在第一次正确解密之后的每个块都是正确的。

Another big problem with strlen(inputz) is that if the strlen() doesn't fall exactly on an 8byte boundary, your decrypt will ultimately fail. I have addressed the problem rather completely as a gist on github.

strlen(inputz)的另一个大问题是,如果strlen()没有完全落在8字节边界上,那么解密最终会失败。我已经完全解决了这个问题,作为github上的一个要点。

#2

Check your encoding.

检查你的编码。

#3

You need to null terminate plain i.e. something like plain[ strlen(dkey_buf) ] = 0 is needed.

你需要null终止plain,即需要像plain [strlen(dkey_buf)] = 0这样的东西。

#4

Aren't there patent restrictions on using/distributing programs that leverage the IBE algorithm?

使用/分发利用IBE算法的程序是否有专利限制?