tesyt.c

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>
#include <openssl/conf.h>
#include <openssl/evp.h>
#include <openssl/err.h>

#define LUNG_MAX 100

void handleErrors(void);
int encrypt(unsigned char *plaintext, int plaintext_len, unsigned char *key,
            unsigned char *iv, unsigned char *ciphertext);
int decrypt(unsigned char *ciphertext, int ciphertext_len, unsigned char *key,
            unsigned char *iv, unsigned char *plaintext);

void string2hex(char* cuv, char* rezultat, int lungime)
{
    for (int i = 0, j = 0; i < lungime; ++i, j += 4)
    {
        sprintf(rezultat + j,"\\x");
        sprintf(rezultat + j + 2, "%02x", cuv[i] & 0xff);
    }
    int dimensiune_hex=strlen(rezultat)-1;
    for(int i=0,j=dimensiune_hex+1;  i<16-lungime; i++,j+=4)
        sprintf(rezultat+j,"\\x20");
}

void hex2string(char* cuv, char* rezultat, int lungime)
{
    char intermediar[100]="";
    char parte[3]="";
    for(int i = 2,j=0;i<lungime;i+=4,j++)
    {
        strncpy(parte,cuv+i,2);
        strcat(intermediar,parte);
    }
    int len = strlen(intermediar);
        for (int i = 0, j = 0; j < len; ++i, j += 2)
    {
        int val[1];
        sscanf(intermediar + j, "%2x", val);
        rezultat[i] = val[0];
        rezultat[i + 1] = '\0';
    }
}

int main (void)
{
    FILE *fisier = fopen("dict.txt", "r");
        char cuvant[LUNG_MAX];
        long contor = 0;
    int dimensiune=0;
        while(fgets(cuvant, sizeof cuvant, fisier) != NULL )
    {
        contor++;
    }
    do
    {
        rewind(fisier);
        srand((unsigned) time(NULL));
        int numar = rand()%contor+1;
        for(int i =0; i<numar;i++)
        {
            fgets(cuvant, sizeof cuvant, fisier);
        }
        dimensiune= strlen(cuvant)-1;
    }while(dimensiune>=16);
    printf("%s\n",cuvant);
        printf("%i\n",dimensiune);
    char hex[100]="";
    char cuvant_intors[100]="";
    string2hex(cuvant,hex,dimensiune);
    int dimensiune_hex=strlen(hex)-1;
    hex2string(hex,cuvant_intors,dimensiune_hex);
    printf("'%s' in hex is %s.\n", cuvant, hex);
    printf("'%s' in string is %s.\n", hex, cuvant_intors);


    unsigned char *key = (unsigned char *)hex;
unsigned char *keyfals = (unsigned char *)"\x01\x02\x03\x04\x05\x06\x07\x08\x09\x0a\x0b\x0c\x0d\x0e\x0f";
    unsigned char *iv = (unsigned char *)"\x01\x02\x03\x04\x05\x06\x07\x08\x09\x0a\x0b\x0c\x0d\x0e\x0f";


unsigned char *plaintext =
        (unsigned char *)"TOMA E INVIDIOS PE PROGRAMUL MEU";

    unsigned char ciphertext[128];

    unsigned char decryptedtext[128];

    int decryptedtext_len, ciphertext_len;

    printf("KEY: %s\n",key);

    ciphertext_len = encrypt (plaintext, strlen ((char *)plaintext), key, iv,
                              ciphertext);

    printf("Ciphertext is:\n");
    BIO_dump_fp (stdout, (const char *)ciphertext, ciphertext_len);
    rewind(fisier);
        int semafor=0;
        contor=0;
    while(fgets(cuvant, sizeof cuvant, fisier) != NULL&&semafor==0 )
        {
            contor++;
            dimensiune= strlen(cuvant)-1;
            string2hex(cuvant,hex,dimensiune);
            dimensiune_hex=strlen(hex)-1;
            decryptedtext_len = decrypt(ciphertext, ciphertext_len, (unsigned char*)hex, iv,decryptedtext);
            printf("%i",decryptedtext_len);
            semafor=1;
            if(decryptedtext_len==-1||decryptedtext_len==47)
            {
                semafor=0;
            }
            else
            {
                printf("\n%s %i\n",cuvant, dimensiune);
                hex2string(hex,cuvant_intors,dimensiune_hex);
                printf("%s.\n",(unsigned char*)hex);
            }
        }
    decryptedtext[decryptedtext_len] = '\0';

    printf("Decrypted text is:\n");
    printf("%s\n", decryptedtext);

    fclose(fisier);
    return 0;
}

void handleErrors(void)
{
    ERR_print_errors_fp(stderr);
    abort();
}

int encrypt(unsigned char *plaintext, int plaintext_len, unsigned char *key,
            unsigned char *iv, unsigned char *ciphertext)
{
    EVP_CIPHER_CTX *ctx;

    int len;

    int ciphertext_len;

    /* Create and initialise the context */
    if(!(ctx = EVP_CIPHER_CTX_new()))
        handleErrors();

    if(1 != EVP_EncryptInit_ex(ctx, EVP_aes_128_cbc(), NULL, key, iv))
        handleErrors();

    if(1 != EVP_EncryptUpdate(ctx, ciphertext, &len, plaintext, plaintext_len))
        handleErrors();
    ciphertext_len = len;

    if(1 != EVP_EncryptFinal_ex(ctx, ciphertext + len, &len))
        handleErrors();
    ciphertext_len += len;

    EVP_CIPHER_CTX_free(ctx);

    return ciphertext_len;
}


int decrypt(unsigned char *ciphertext, int ciphertext_len, unsigned char *key,
            unsigned char *iv, unsigned char *plaintext)
{
    EVP_CIPHER_CTX *ctx;
    int trash=0;
    int len;

    int plaintext_len;

    /* Create and initialise the context */
    if(!(ctx = EVP_CIPHER_CTX_new()))
        handleErrors();
    int unu=EVP_DecryptInit_ex(ctx, EVP_aes_128_cbc(), NULL, key, iv);
    if(1 != unu)
       trash++;
   int doi=EVP_DecryptUpdate(ctx, plaintext, &len, ciphertext, ciphertext_len);
    if(1 != doi)
  trash++;
    plaintext_len = len;
     int trei=EVP_DecryptFinal_ex(ctx, plaintext + len, &len);
    if(1 != trei)
       trash++;
    plaintext_len += len;
    memset(plaintext + plaintext_len, 0, plaintext_len);
    EVP_CIPHER_CTX_free(ctx);
if(trei==0)
return -1;
    return plaintext_len;
}