AES_ctr128_encrypt字符串，反之亦然ANSI C [英] AES_ctr128_encrypt string and vice versa ANSI C

问题描述

我需要插入一个128位十六进制的密钥来加密（16）一个字符串内容，然后我想将该字符串（crypted）解密为纯文本。

有时我有相同的输出，但并不总是正确的！我正在做这件事吗？

我现在的代码：

  #include< openssl / aes.h> 
 #include< openssl / rand.h> 
 #include< openssl / hmac.h> 
 #include< openssl / buffer.h> 
 #include< stdio.h> 
 #include< string.h> 
 #include< stdlib.h> 
 #include< math.h> 
 
 //代码示例使用partail代码：http://stackoverflow.com/questions/3141860/aes-ctr-256-encryption-mode-of-operation-on-openssl 
 //大部分在ctr_状态和init_ctr函数中。 
 
 struct ctr_state 
 {
 unsigned char ivec [AES_BLOCK_SIZE]; 
 unsigned int num; 
 unsigned char ecount [AES_BLOCK_SIZE]; 
}; 
 
 
 AES_KEY键; 
 
 int bytes_read，bytes_written; 
 unsigned char indata [AES_BLOCK_SIZE]; 
 unsigned char outdata [AES_BLOCK_SIZE]; 
 unsigned char iv [AES_BLOCK_SIZE]; // 16？ 
 struct ctr_state state; 
 
 
 int init_ctr（struct ctr_state * state，const unsigned char iv [16]）
 {
 / * O aes_ctr128_encrypt exige um'num'e um'ecount 'definidos一个零na齐拉chamada。 * / 
 state-> num = 0; 
 memset（state-> ecount，0，AES_BLOCK_SIZE）; // 16？ 
 
 / *Inicilaizaçãodo contador no'ivec'a 0 * / 
 memset（state-> ecount，0，16）; // 16？ 
 
 / * Copia o IV para o'ivec'* / 
 memcpy（state-> ivec，iv，16）; // 16？ 
} 
 
 char * TextEncrypt（const unsigned char * enc_key，char * text）
 {
 // Cria vector com valoresaleatórios
 if（！ RAND_bytes（iv，AES_BLOCK_SIZE））
 {
 printf（Erro：Nãofoi possivel criar bytes aleatorios.\\\
）; 
 exit（1）; 
} 
 
 // Inicializa a chave deencriptação
 if（AES_set_encrypt_key（enc_key，128，& key）< 0）
 {
 fprintf （stderr，Nao foipossíveldefinir chave de encrefacao）; 
 exit（1）; 
} 
 
 init_ctr（& state，iv）; // Chamada do contador 
 
 bytes_read = strlen（text）; 
 
 AES_set_encrypt_key（enc_key，128，& key）; 
 
 // Encripta em blocos de 16 bytes e guarda o texto cifrado numa string  - > outdata 
 AES_ctr128_encrypt（text，outdata，bytes_read，& key，state.ivec，state.ecount，& state.num）; 
 
 fflush（stdin）; 
返回outdata; 
} 
 
 char * TextDecrypt（const unsigned char * enc_key，unsigned char * cypherText）
 {
 
 //Inicializaçãoda Chave deencriptação
 if（AES_set_encrypt_key（enc_key，128，& key）< 0）
 {
 fprintf（stderr，Nao foi possivel definir chave de decodificacao）; 
 exit（1）; 
} 
 
 init_ctr（& state，iv）; // Chamada do contador 
 
 // Encripta em blocos de 16 bytes e escreve o ficheiro output.txt cifrado 
 bytes_read = strlen（cypherText）; 
 
 AES_set_encrypt_key（enc_key，128，& key）; 
 
 AES_ctr128_encrypt（cypherText，outdata，bytes_read，& key，state.ivec，state.ecount，& state.num）; 
 
 fflush（stdin）; 
返回outdata; 
} 
 
 int main（int argc，char * argv []）
 {
 char text [] =我的程序的文本测试; 
 
 //接收十六进制128位密钥
 unsigned const char * key =1234567812345678; 
 // unsigned const char * key =9EF4BCDE; 
 char * cipher，*解密; 
 
 printf（清洁文本：％s\\\
，文本）; 
 
 cipher = TextEncrypt（key，text）; 
 printf（Chiper文本：％s\\\
，cipher）; 
 
 decryptpted = TextDecrypt（key，cipher）; 
 printf（解密文本：％s\\\
，解密）; 
 
 getc（stdin）; 
 return 0; 
} 
  

有人可以帮忙吗？谢谢。

解决方案

您正在CipherText上使用strlen（），它可能包含空字节。这将导致bytes_read小于要解密的数据的实际长度。

I need to insert a 128 hex key to cipher by blocks (16) a string content, and then I want to decrypyt that string(crypted) to a plain text.

Sometimes I have the same output, but not totaly correct! I am doing this right?!

My code now:

#include <openssl/aes.h>
#include <openssl/rand.h> 
#include <openssl/hmac.h>
#include <openssl/buffer.h>
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <math.h>

// Code example uses partail code from: http://stackoverflow.com/questions/3141860/aes-ctr-256-encryption-mode-of-operation-on-openssl
// Mostly in the ctr_ state, and init_ctr functions. 

struct ctr_state 
{ 
    unsigned char ivec[AES_BLOCK_SIZE];  
    unsigned int num; 
    unsigned char ecount[AES_BLOCK_SIZE]; 
}; 


AES_KEY key; 

int bytes_read, bytes_written;   
unsigned char indata[AES_BLOCK_SIZE]; 
unsigned char outdata[AES_BLOCK_SIZE];
unsigned char iv[AES_BLOCK_SIZE]; //16?
struct ctr_state state;


int init_ctr(struct ctr_state *state, const unsigned char iv[16])
{        
    /*O aes_ctr128_encrypt exige um 'num' e um 'ecount' definidos a zero na primeira chamada. */
    state->num = 0;
    memset(state->ecount, 0, AES_BLOCK_SIZE); //16?

    /* Inicilaização do contador no 'ivec' a 0 */
    memset(state->ecount, 0, 16); //16?

    /* Copia o IV para o 'ivec' */
    memcpy(state->ivec, iv, 16); //16?
}

char * TextEncrypt(const unsigned char* enc_key, char * text)
{ 
    //Cria vector com valores aleatórios
    if(!RAND_bytes(iv, AES_BLOCK_SIZE))
    {
        printf("Erro: Não foi possivel criar bytes aleatorios.\n");
        exit(1);    
    }

    //Inicializa a chave de encriptação
    if (AES_set_encrypt_key(enc_key, 128, &key) < 0)
    {
        fprintf(stderr, "Nao foi possível definir chave de encriptacao.");
        exit(1);
    }

    init_ctr(&state, iv); //Chamada do contador

    bytes_read = strlen(text);

    AES_set_encrypt_key(enc_key, 128, &key);    

    //Encripta em blocos de 16 bytes e guarda o texto cifrado numa string -> outdata
    AES_ctr128_encrypt(text, outdata, bytes_read, &key, state.ivec, state.ecount, &state.num);

    fflush(stdin);
    return outdata;
}

char * TextDecrypt(const unsigned char* enc_key, unsigned char* cypherText)
{       

    //Inicialização da Chave de encriptação 
    if (AES_set_encrypt_key(enc_key, 128, &key) < 0)
    {
        fprintf(stderr, "Nao foi possível definir chave de decodificacao.");
        exit(1);
    }

    init_ctr(&state, iv);//Chamada do contador

    //Encripta em blocos de 16 bytes e escreve o ficheiro output.txt cifrado         
    bytes_read = strlen(cypherText);    

    AES_set_encrypt_key(enc_key, 128, &key);

    AES_ctr128_encrypt(cypherText, outdata, bytes_read, &key, state.ivec, state.ecount, &state.num);

    fflush(stdin);
    return outdata;
}

int main(int argc, char *argv[])
{
    char text [] = "Text test to my program";

    //Receive hexadecimal 128 bits key 
    unsigned const char * key = "1234567812345678";
    //unsigned const char * key = "9EF4BCDE";   
    char * cipher, * decrypted;

    printf("Clean text: %s\n", text);

    cipher = TextEncrypt(key, text);
    printf("Chiper text: %s\n", cipher);

    decrypted = TextDecrypt(key, cipher);
    printf("Decrypted text: %s\n", decrypted);

    getc(stdin);
    return 0;
}

Can anybody help, please?! Thanks.

解决方案

You are using strlen() on your CipherText, which may contain null bytes. This will cause bytes_read to be less than the actual length of the data you want to decrypt.

这篇关于AES_ctr128_encrypt字符串，反之亦然ANSI C的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！