Simmetrik shifrlash va rejimlar

function bloklar(string $baytlar, int $olcham = 16): string
{
    $natija = [];
    foreach (str_split(bin2hex($baytlar), $olcham * 2) as $i => $b) {
        $natija[] = sprintf('  %d: %s', $i, $b);
    }
    return implode(PHP_EOL, $natija);
}

echo 'AES blok o\'lchami: ',
    openssl_cipher_iv_length('aes-256-cbc'), ' bayt', PHP_EOL;

foreach (['aes-128-cbc', 'aes-192-cbc', 'aes-256-cbc'] as $shifr) {
    // kalit uzunligini nomidan olamiz
    $bit = (int) explode('-', $shifr)[1];
    printf('%-12s kalit: %2d bayt (%d bit)%s', $shifr, $bit / 8, $bit, PHP_EOL);
}

$kalit = hex2bin(str_repeat('11', 32));

// Ataylab takrorlanuvchi ma'lumot
$matn = str_repeat('AAAABBBBCCCCDDDD', 4);   // 4 ta bir xil blok

echo 'ochiq matn (4 blok, hammasi bir xil):', PHP_EOL;
echo bloklar($matn), PHP_EOL, PHP_EOL;

$shifr = openssl_encrypt($matn, 'aes-256-ecb', $kalit,
    OPENSSL_RAW_DATA | OPENSSL_ZERO_PADDING);

echo 'ECB bilan shifrlangan:', PHP_EOL;
echo bloklar($shifr), PHP_EOL;

$kalit = hex2bin(str_repeat('11', 32));

// 8x8 "rasm": 1 - qora nuqta, 0 - oq
$rasm = [
    '0000000000000000', '0011111111110000', '0011000000110000',
    '0011000000110000', '0011111111110000', '0011000000110000',
    '0011000000110000', '0000000000000000',
];

echo 'ASL "RASM":', PHP_EOL;
foreach ($rasm as $q) {
    echo '  ', strtr($q, ['0' => '.', '1' => '#']), PHP_EOL;
}

// Har qatorni alohida blok sifatida ECB bilan shifrlaymiz
echo PHP_EOL, 'ECB dan KEYIN (har qator - bitta blok):', PHP_EOL;
foreach ($rasm as $q) {
    $s = openssl_encrypt($q, 'aes-256-ecb', $kalit,
        OPENSSL_RAW_DATA | OPENSSL_ZERO_PADDING);
    echo '  ', substr(bin2hex($s), 0, 32), PHP_EOL;
}

$kalit = hex2bin(str_repeat('11', 32));
$iv = hex2bin(str_repeat('22', 16));

$matn = str_repeat('AAAABBBBCCCCDDDD', 4);

$shifr = openssl_encrypt($matn, 'aes-256-cbc', $kalit,
    OPENSSL_RAW_DATA | OPENSSL_ZERO_PADDING, $iv);

echo 'CBC bilan (bir xil ochiq bloklar):', PHP_EOL;
echo bloklar($shifr), PHP_EOL;

echo PHP_EOL, 'endi bloklar HAR XIL', PHP_EOL;

$kalit = hex2bin(str_repeat('11', 32));
$matn = 'Bir xil xabar!!!';

// Bir xil matn, TURLI IV
foreach (['33', '44', '55'] as $bayt) {
    $iv = hex2bin(str_repeat($bayt, 16));
    $s = openssl_encrypt($matn, 'aes-256-cbc', $kalit,
        OPENSSL_RAW_DATA | OPENSSL_ZERO_PADDING, $iv);
    printf('IV %s...: %s%s', $bayt . $bayt, bin2hex($s), PHP_EOL);
}

$kalit = hex2bin(str_repeat('11', 32));
$iv = hex2bin(str_repeat('22', 16));

// Ikki blokli xabar
$matn = 'AAAAAAAAAAAAAAAA' . 'rol=user;id=1234';

$shifr = openssl_encrypt($matn, 'aes-256-cbc', $kalit,
    OPENSSL_RAW_DATA | OPENSSL_ZERO_PADDING, $iv);

echo 'asl matn:  ', $matn, PHP_EOL;
echo 'ochilgan:  ', openssl_decrypt($shifr, 'aes-256-cbc', $kalit,
    OPENSSL_RAW_DATA | OPENSSL_ZERO_PADDING, $iv), PHP_EOL;

// Hujumchi BIRINCHI blokning bir baytini o'zgartiradi
$buzilgan = $shifr;
$buzilgan[5] = chr(ord($buzilgan[5]) ^ 0x04);

$natija = openssl_decrypt($buzilgan, 'aes-256-cbc', $kalit,
    OPENSSL_RAW_DATA | OPENSSL_ZERO_PADDING, $iv);

echo PHP_EOL, 'shifrmatn ozgartirilgandan keyin:', PHP_EOL;
echo 'xato berdimi: ', $natija === false ? 'ha' : 'YOQ', PHP_EOL;
echo '1-blok:    ', bin2hex(substr($natija, 0, 16)), PHP_EOL;
echo '2-blok:    ', substr($natija, 16), PHP_EOL;

$kalit = hex2bin(str_repeat('11', 32));
$iv = hex2bin(str_repeat('22', 16));

foreach (['a', 'salom', str_repeat('x', 15), str_repeat('x', 16)] as $m) {
    // OPENSSL_ZERO_PADDING SIZ - PKCS#7 to'ldirish ishlatiladi
    $s = openssl_encrypt($m, 'aes-256-cbc', $kalit, OPENSSL_RAW_DATA, $iv);
    printf('%2d bayt matn -> %2d bayt shifr%s',
        strlen($m), strlen($s), PHP_EOL);
}

$kalit = hex2bin(str_repeat('11', 32));
$nonce = hex2bin(str_repeat('33', 16));

foreach (['a', 'salom', str_repeat('x', 100)] as $m) {
    $s = openssl_encrypt($m, 'aes-256-ctr', $kalit, OPENSSL_RAW_DATA, $nonce);
    printf('%3d bayt matn -> %3d bayt shifr%s',
        strlen($m), strlen($s), PHP_EOL);
}

echo PHP_EOL, 'CTR da toldirish YOQ - uzunlik bir xil', PHP_EOL;

$mavjud = openssl_get_cipher_methods();

foreach (['aes-256-ecb', 'aes-256-cbc', 'aes-256-ctr',
          'aes-256-gcm', 'chacha20-poly1305'] as $c) {
    printf('%-20s %s%s', $c,
        in_array($c, $mavjud, true) ? 'mavjud' : 'yoq', PHP_EOL);
}