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#include <docopt/docopt.h>
#include <docopt/docopt_value.h>
#include <fcntl.h>
#include <gcrypt.h>
#include <termios.h>
#include <unistd.h>
#include <cstring>
#include <iostream>
#include <memory>
#include <stdexcept>
#ifndef PROJECT_VERSION
#warning Use hardcoded version
#define PROJECT_VERSION "0.1.0"
#endif
auto get_version() {
/* TODO */
return "aes v" PROJECT_VERSION;
}
auto get_usage() {
/* TODO */
return get_version() + std::string(R"(
Usage:
aes [options]
Options:
-h, --help Pring this message
-v, --version Print version and exit
-d, --decrypt Decrypt data
-p, --password=PASSWORD Use password [default: prompt]
-k, --key=KEY Use key instead password [default: ]
-l, --last=LAST Size of last block [default: 0]
-b, --bits=BITS Use aes with specified bits [default: 256]
)");
}
gcry_error_t proccess_encrypt(gcry_cipher_hd_t hd,
const char* block_in,
char* block_out) {
return gcry_cipher_encrypt(hd, block_out, 16, block_in, 16);
}
gcry_error_t proccess_decrypt(gcry_cipher_hd_t hd,
const char* block_in,
char* block_out) {
return gcry_cipher_decrypt(hd, block_out, 16, block_in, 16);
}
void try_gcry(gcry_error_t err) {
auto code = gcry_err_code(err);
if (code != 0) {
throw std::runtime_error((const char*)gcry_err_source(err));
}
}
int main(int argc, const char** argv) {
auto args = docopt::docopt(get_usage(), {argv + 1, argv + argc}, true,
get_version());
auto decrypt = args.at("--decrypt").asBool();
auto password = args.at("--password").asString();
auto key = args.at("--key").asString();
auto bits = args.at("--bits").asLong();
auto last = args.at("--last").asLong();
try {
if (password != "prompt" && key != "") {
throw std::invalid_argument(
"using --password and --key at some time is imposible.");
}
if (last > 15 || last < 0) {
throw std::invalid_argument("--last should be between 0 and 15.");
}
if (bits != 256 && bits != 128) {
throw std::invalid_argument("--bits should be 128 or 256.");
}
if (key.size() != 0 && key.size() != (bits >> 1)) {
throw std::invalid_argument("--key size should be equal BITS/2");
}
if (decrypt == false && last != 0) {
std::cerr << "Note: using --last possible only with --decrypt\n";
}
} catch (const std::invalid_argument& e) {
std::cerr << e.what() << '\n';
return 1;
}
size_t key_size = bits >> 2;
std::unique_ptr<char[]> key_arr(new char[key_size]);
if (key == "") {
if (password == "prompt") {
password = getpass("Enter password:");
}
gcry_md_hd_t md_handle;
try_gcry(gcry_md_open(&md_handle, GCRY_MD_SHA512, 0));
gcry_md_write(md_handle, password.data(), password.size());
std::memcpy(key_arr.get(), gcry_md_read(md_handle, GCRY_MD_SHA512),
key_size);
gcry_md_close(md_handle);
} else {
for (size_t i = 0; i < key_size; ++i) {
char buf[3]{0, 0, 0};
buf[0] = key[(i << 1) + 0];
buf[1] = key[(i << 1) + 1];
buf[2] = 0;
key_arr[i] = std::strtol(buf, nullptr, 16);
}
}
int algo = GCRY_CIPHER_AES256;
if (bits == 128) {
algo = GCRY_CIPHER_AES128;
}
gcry_cipher_hd_t hd;
try_gcry(gcry_cipher_open(&hd, algo, GCRY_CIPHER_MODE_XTS, 0));
try_gcry(gcry_cipher_setkey(hd, key_arr.get(), key_size));
auto proccess = decrypt ? proccess_decrypt : proccess_encrypt;
while (std::cin.good()) {
char block_in[16];
char block_out[16];
std::cin.read(block_in, 16);
size_t readed = std::cin.gcount();
if (readed == 0)
break;
if (readed != 16) {
std::cerr << "last block size: " << readed << '\n';
std::memset(block_in + readed, 0, 16 - readed);
}
try_gcry(proccess(hd, block_in, block_out));
if (std::cin.peek() == EOF) {
if (last != 0) {
std::cout.write(block_out, last);
break;
}
}
std::cout.write(block_out, 16);
}
gcry_cipher_close(hd);
return 0;
}
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