[c] changed cfich_chacha20.c to handle any file size
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68d5728ab4
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cddc411a19
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SHA256:JiuxZNdA5bRWXPMUJChI0AQ75yC+cXY4xM0IaVwEVys
1 changed files with 100 additions and 181 deletions
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@ -1,3 +1,5 @@
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#include <openssl/err.h>
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#include <openssl/evp.h>
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#include <openssl/rand.h>
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#include <stdio.h>
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#include <stdlib.h>
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@ -7,33 +9,50 @@ void setup(char *key_file) {
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FILE *f = fopen(key_file, "wb");
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if (f == NULL) {
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printf("Error opening file\n");
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goto close;
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return;
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}
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unsigned char key_bytes[32];
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if (RAND_bytes(key_bytes, 32) != 1) {
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printf("Error generating random bytes\n");
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goto close;
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fclose(f);
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return;
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}
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if (fwrite(key_bytes, 1, 32, f) != 32) {
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printf("Error writing to file\n");
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goto close;
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}
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goto close;
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close:
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fclose(f);
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}
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int encrypt(char *input_file, char *key_file) {
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FILE *fkey = fopen(key_file, "rb");
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int chacha20(const char *input_file, const char *output_file, const char *key_file, int enc) {
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int BUF_SIZE = 1024;
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int u_len = 0, f_len = 0;
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unsigned char input_buf[BUF_SIZE], output_buf[BUF_SIZE];
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FILE *finput = fopen(input_file, "rb");
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if (finput == NULL) {
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printf("Error opening input file\n");
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return 1;
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}
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// Open output file
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FILE *foutput = fopen(output_file, "wb");
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if (foutput == NULL) {
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printf("Error opening output file\n");
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fclose(finput);
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return 1;
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}
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FILE *fkey = fopen(key_file, "rb");
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if (fkey == NULL) {
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printf("Error opening key file\n");
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return 1;
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}
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unsigned char key_bytes[32];
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if (fread(key_bytes, 1, 32, fkey) != 32) {
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printf("Error reading key from file\n");
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@ -42,204 +61,104 @@ int encrypt(char *input_file, char *key_file) {
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}
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fclose(fkey);
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FILE *finput = fopen(input_file, "rb");
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if (finput == NULL) {
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printf("Error opening input file\n");
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return 1;
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}
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// Determining file size
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fseek(finput, 0, SEEK_END);
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unsigned long fsize = ftell(finput);
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rewind(finput);
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unsigned char *plaintext = malloc(fsize * sizeof(unsigned char));
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if (plaintext == NULL) {
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printf("Error allocating memory\n");
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fclose(finput);
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return 1;
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}
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if (fread(plaintext, 1, fsize, finput) != fsize) {
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printf("Error reading file\n");
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fclose(finput);
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free(plaintext);
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return 1;
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}
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fclose(finput);
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unsigned char nonce[16];
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if (RAND_bytes(nonce, 16) != 1) {
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printf("Error generating nonce\n");
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free(plaintext);
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return 1;
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}
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// Encrypt the plaintext using chacha20
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unsigned char ciphertext[fsize];
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EVP_CIPHER_CTX *ctx;
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EVP_CIPHER_CTX *ctx = NULL;
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if (!(ctx = EVP_CIPHER_CTX_new())) {
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printf("Error creating context\n");
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free(plaintext);
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fclose(finput);
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fclose(foutput);
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return 1;
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}
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if (EVP_EncryptInit_ex(ctx, EVP_chacha20(), NULL, key_bytes, nonce) != 1) {
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printf("Error initializing encryption\n");
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free(plaintext);
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EVP_CIPHER_CTX_free(ctx);
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return 1;
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}
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int len;
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if (EVP_EncryptUpdate(ctx, ciphertext, &len, plaintext, fsize) != 1) {
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printf("Error encrypting\n");
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EVP_CIPHER_CTX_free(ctx);
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free(plaintext);
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// If enc is 1, then we are encrypting, else we are decrypting
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// If we are encrypting, we need to generate an IV
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// If we are decrypting, we need to read the IV from the file
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unsigned char iv[16];
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if (enc) {
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if (RAND_bytes(iv, 16) != 1) {
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printf("Error generating IV\n");
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return 1;
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}
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if (fwrite(iv, 1, 16, foutput) != 16) {
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printf("Error writing IV to file\n");
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return 1;
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}
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} else {
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if (fread(iv, 1, 16, finput) != 16) {
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printf("Error reading IV from file\n");
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return 1;
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}
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}
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if (EVP_EncryptFinal_ex(ctx, ciphertext + len, &len) != 1) {
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printf("Error finalizing encryption\n");
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if (EVP_CipherInit_ex(ctx, EVP_chacha20(), NULL, key_bytes, iv, enc) != 1) {
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fprintf(stderr, "ERROR: EVP_CipherInit_ex failed. OpenSSL error: %s\n",
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ERR_error_string(ERR_get_error(), NULL));
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EVP_CIPHER_CTX_free(ctx);
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free(plaintext);
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return 1;
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}
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// Add the nonce to the beginning of the file
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char *nonce_and_ciphertext = malloc(16 + (fsize * sizeof(unsigned char)));
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memcpy(nonce_and_ciphertext, nonce, 16);
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memcpy(nonce_and_ciphertext + 16, ciphertext, fsize);
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int read_size, len;
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while ((read_size = fread(input_buf, 1, BUF_SIZE, finput)) > 0) {
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printf("Read %d bytes, passing through CipherUpdate...\n", read_size);
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if (EVP_CipherUpdate(ctx, output_buf, &len, input_buf, read_size) != 1) {
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fprintf(stderr, "ERROR: EVP_CipherUpdate failed. OpenSSL error: %s\n",
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ERR_error_string(ERR_get_error(), NULL));
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fclose(finput);
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fclose(foutput);
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return 1;
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}
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printf("\tGot back %d bytes from CipherUpdate...\n", len);
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printf("Writing %d bytes to %s...\n", len, output_file);
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if (fwrite(output_buf, 1, len, foutput) != len) {
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printf("Error writing to output file\n");
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return 1;
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}
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printf("\tWrote %d bytes\n", len);
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u_len += len;
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}
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if (read_size == -1) {
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fprintf(stderr, "ERROR: Reading from the file %s failed.\n", input_file);
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}
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// Create output file
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if (EVP_CipherFinal_ex(ctx, output_buf, &f_len) != 1) {
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fprintf(stderr, "ERROR: EVP_CipherFinal_ex failed. OpenSSL error: %s\n",
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ERR_error_string(ERR_get_error(), NULL));
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fclose(finput);
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fclose(foutput);
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return 1;
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}
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printf("u_len: %d, f_len: %d\n", u_len, f_len);
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if (f_len) {
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printf("Writing final %d bytes to %s...\n", f_len, output_file);
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if (fwrite(output_buf, 1, f_len, foutput) != f_len) {
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printf("Error writing to output file\n");
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fclose(finput);
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fclose(foutput);
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return 1;
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}
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}
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printf("\tWrote last %d bytes\n", f_len);
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fclose(finput);
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fclose(foutput);
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return 0;
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}
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int encrypt(char *input_file, char *key_file) {
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char *output_file = malloc(strlen(input_file) + 5);
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strcpy(output_file, input_file);
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strcat(output_file, ".enc");
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FILE *foutput = fopen(output_file, "wb");
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if (foutput == NULL) {
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printf("Error opening output file\n");
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EVP_CIPHER_CTX_free(ctx);
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return 1;
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}
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if (fwrite(nonce_and_ciphertext, 1, 16 + fsize, foutput) != (16 + fsize)) {
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printf("Error writing to output file\n");
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fclose(foutput);
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free(plaintext);
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free(nonce_and_ciphertext);
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free(output_file);
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EVP_CIPHER_CTX_free(ctx);
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return 1;
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}
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fclose(foutput);
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free(plaintext);
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free(nonce_and_ciphertext);
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free(output_file);
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EVP_CIPHER_CTX_free(ctx);
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chacha20(input_file, output_file, key_file, 1);
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return 0;
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}
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int decrypt(char *input_file, char *key_file) {
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FILE *fkey = fopen(key_file, "rb");
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if (fkey == NULL) {
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printf("Error opening key file\n");
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return 1;
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}
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unsigned char key_bytes[32];
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if (fread(key_bytes, 1, 32, fkey) != 32) {
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printf("Error reading key from file\n");
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fclose(fkey);
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return 1;
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}
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fclose(fkey);
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FILE *finput = fopen(input_file, "rb");
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if (finput == NULL) {
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printf("Error opening input file\n");
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return 1;
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}
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// Determining file size
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fseek(finput, 0, SEEK_END);
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unsigned long fsize = ftell(finput);
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rewind(finput);
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unsigned char *nonce_and_ciphertext = malloc(fsize * sizeof(unsigned char));
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if (nonce_and_ciphertext == NULL) {
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printf("Error allocating memory\n");
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fclose(finput);
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return 1;
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}
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if (fread(nonce_and_ciphertext, 1, fsize, finput) != fsize) {
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printf("Error reading file\n");
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fclose(finput);
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free(nonce_and_ciphertext);
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return 1;
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}
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fclose(finput);
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unsigned char nonce[16];
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memcpy(nonce, nonce_and_ciphertext, 16);
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unsigned char *ciphertext = malloc((fsize * sizeof(unsigned char)) - 16);
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memcpy(ciphertext, nonce_and_ciphertext + 16, fsize - 16);
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// Decrypt the ciphertext using chacha20
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unsigned char plaintext[fsize - 16];
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EVP_CIPHER_CTX *ctx;
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if (!(ctx = EVP_CIPHER_CTX_new())) {
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printf("Error creating context\n");
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free(nonce_and_ciphertext);
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free(ciphertext);
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return 1;
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}
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if (EVP_DecryptInit_ex(ctx, EVP_chacha20(), NULL, key_bytes, nonce) != 1) {
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printf("Error initializing decryption\n");
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free(nonce_and_ciphertext);
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free(ciphertext);
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return 1;
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}
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int len;
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if (EVP_DecryptUpdate(ctx, plaintext, &len, ciphertext, fsize - 16) != 1) {
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printf("Error decrypting\n");
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free(nonce_and_ciphertext);
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free(ciphertext);
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return 1;
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}
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if (EVP_DecryptFinal_ex(ctx, plaintext + len, &len) != 1) {
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printf("Error finalizing decryption\n");
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free(nonce_and_ciphertext);
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free(ciphertext);
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return 1;
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}
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free(ciphertext);
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// Create output file
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char *output_file = malloc(strlen(input_file) + 5);
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strcpy(output_file, input_file);
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strcat(output_file, ".dec");
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FILE *foutput = fopen(output_file, "wb");
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if (foutput == NULL) {
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printf("Error opening output file\n");
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return 1;
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}
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if (fwrite(plaintext, 1, fsize - 16, foutput) != (fsize - 16)) {
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printf("Error writing to output file\n");
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fclose(foutput);
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free(nonce_and_ciphertext);
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free(output_file);
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return 1;
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}
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fclose(foutput);
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free(nonce_and_ciphertext);
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free(output_file);
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chacha20(input_file, output_file, key_file, 0);
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return 0;
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}
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