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#include "rc4.h"
char* rc4_ncurses_get_password(void) {
unsigned char* pass = malloc(PASS_MAX + 1);
pointer_alloc_check(pass);
initscr();
noecho(); // Doesn't echo chars when typed
unsigned int c, i;
do {
printw("Enter Password (32 character max): ");
memset(pass, '\0', PASS_MAX + 1);
i = 0, c = 0;
while (c != '\n' && (c = (unsigned) getch())) {
if (c != BACKSPACE) {
pass[i] = (char) c;
i++;
if (i > PASS_MAX) { // Breaks loop if more than max
c = '\n';
printw("\n");
}
} else if (i > 0) // If backspace
pass[i - 1] = '\0';
}
} while (i > PASS_MAX);
clear();
endwin();
return (char*) pass;
}
void rc4_encode_string(String* pString, const char password[PASS_MAX]) {
int keySchedule[256];
size_t key_len = strlen(password);
int j = 0, out;
// KEY EXCHANGE
for (int i = 0; i < KEY_SCHEDULE_LENGTH; i++)
keySchedule[i] = i;
int temp;
for (int i = 0; i < KEY_SCHEDULE_LENGTH; i++) {
j = (j + keySchedule[i] + password[i % key_len]) % KEY_SCHEDULE_LENGTH;
temp = keySchedule[i];
keySchedule[i] = keySchedule[j];
keySchedule[j] = temp;
}
// PRGA
int i = 0;
j = 0;
for (size_t k = 0; k < pString->len; k++) {
i = (i + 1) % KEY_SCHEDULE_LENGTH;
j = (j + keySchedule[i]) % KEY_SCHEDULE_LENGTH;
temp = keySchedule[i];
keySchedule[i] = keySchedule[j];
keySchedule[j] = temp;
out = (unsigned char) keySchedule[(keySchedule[i] + keySchedule[j]) % KEY_SCHEDULE_LENGTH];
pString->data[k] ^= out; // XOR to encode/decode
}
}
int rc4_ncurses_decrypt_string(String* pString, char** password_ref) {
int status = 1;
Json* jobj = json_tokener_parse(pString->data); // Make sure portfolio is JSON formatted
if (jobj == NULL || !json_object_is_type(jobj, json_type_array)) { // if not JSON array, decrypt
char* password = rc4_ncurses_get_password();
puts("Decrypting portfolio...");
rc4_encode_string(pString, password); // Decode using password
jobj = json_tokener_parse(pString->data);
if (jobj == NULL || !json_object_is_type(jobj, json_type_array)) { // Wrong pw if not JSON[]
puts("Wrong password!");
status = 0; // false
free(password);
} else if (password_ref != NULL) // If provided a string reference, strcpy
*password_ref = password; // This is used for re-encrypting the portfolio
else free(password);
}
json_object_put(jobj);
return status;
}
void portfolio_write_encrypt_decrypt(int crypt_opt) {
char* password = NULL;
String* pString = file_get_string(portfolio_file_path);
if (pString == NULL) // Error reading portfolio
return;
if (!rc4_ncurses_decrypt_string(pString, &password)) // Error decrypting
goto cleanup;
if (crypt_opt == ENCRYPT && password != NULL) // Trying to encrypt an encrypted portfolio
GOTO_CLEAN_MSG("Portfolio is already encrypted.")
if (crypt_opt == DECRYPT && password == NULL) // Trying to decrypt a plaintext portfolio
GOTO_CLEAN_MSG("Portfolio isn't encrypted.")
if (crypt_opt == DECRYPT) {
string_write_file(pString, portfolio_file_path);
GOTO_CLEAN_MSG("Decrypted successfully")
}
// ENCRYPT
password = rc4_ncurses_get_password();
puts("You will be asked to enter your password again to make sure the entries match.");
sleep(2); // Sleep so user can read above message before ncurses initscr()
char* password_check = rc4_ncurses_get_password(); // Get password a second time
if (strcmp(password, password_check) != 0) { // Make sure the two passwords are the same
free(password_check);
GOTO_CLEAN_MSG("Passwords do not match!")
}
rc4_encode_string(pString, password);
string_write_file(pString, portfolio_file_path);
puts("Encrypted successfully");
free(password_check);
cleanup: // CLEANUP
free(password);
string_destroy(&pString);
}
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