Kalit almashinuvi

// Darslik uchun qat'iy kalitlar. Real tizimda har sessiyaga yangi juft.
const ALISA_MAXFIY = <<<'PEM'
-----BEGIN EC PRIVATE KEY-----
MHcCAQEEICidPlZx2J4A1sx7b97ButVhDSTQxsICIr+MxYXTse6noAoGCCqGSM49
AwEHoUQDQgAEe39CeoZQUWyQbRVU6L8lQ8S8kFR7ls40P0w/bPznljOVza657HDq
DmUa5skHMX0hJEVP8cb4DFfYjWWQSCXr7Q==
-----END EC PRIVATE KEY-----
PEM;

const ALISA_OCHIQ = <<<'PEM'
-----BEGIN PUBLIC KEY-----
MFkwEwYHKoZIzj0CAQYIKoZIzj0DAQcDQgAEe39CeoZQUWyQbRVU6L8lQ8S8kFR7
ls40P0w/bPznljOVza657HDqDmUa5skHMX0hJEVP8cb4DFfYjWWQSCXr7Q==
-----END PUBLIC KEY-----
PEM;

const BOBUR_MAXFIY = <<<'PEM'
-----BEGIN EC PRIVATE KEY-----
MHcCAQEEIDUTZL094fJVDFkFG5S9+7yYZ9m9ywlhnRb0Hd4JPL1coAoGCCqGSM49
AwEHoUQDQgAEc/7W8mWzxt5PAlQVNSUcWBb58kVHJq9onVftuVmK4SVkcYOO/zCz
p+8FVN/umE3wA8Pbka2NahVJPqxj+EKzWg==
-----END EC PRIVATE KEY-----
PEM;

const BOBUR_OCHIQ = <<<'PEM'
-----BEGIN PUBLIC KEY-----
MFkwEwYHKoZIzj0CAQYIKoZIzj0DAQcDQgAEc/7W8mWzxt5PAlQVNSUcWBb58kVH
Jq9onVftuVmK4SVkcYOO/zCzp+8FVN/umE3wA8Pbka2NahVJPqxj+EKzWg==
-----END PUBLIC KEY-----
PEM;

function korsat(string $nom, string $qiymat): void
{
    printf("%-22s %s%s", $nom . ':', $qiymat, PHP_EOL);
}

// Alisa o'z maxfiy kaliti + Boburning OCHIQ kaliti
$alisaMaxfiy = openssl_pkey_get_private(ALISA_MAXFIY);
$umumiy1 = openssl_pkey_derive(BOBUR_OCHIQ, $alisaMaxfiy, 32);

// Bobur o'z maxfiy kaliti + Alisaning OCHIQ kaliti
$boburMaxfiy = openssl_pkey_get_private(BOBUR_MAXFIY);
$umumiy2 = openssl_pkey_derive(ALISA_OCHIQ, $boburMaxfiy, 32);

korsat('Alisa hisobladi', bin2hex($umumiy1));
korsat('Bobur hisobladi', bin2hex($umumiy2));
korsat('bir xilmi', hash_equals($umumiy1, $umumiy2) ? 'HA' : 'yoq');

$alisaMaxfiy = openssl_pkey_get_private(ALISA_MAXFIY);
$xomSir = openssl_pkey_derive(BOBUR_OCHIQ, $alisaMaxfiy, 32);

korsat('xom sir', bin2hex($xomSir));

// XOM SIRNI KALIT SIFATIDA ISHLATMANG - u bir tekis taqsimlanmagan.
// HKDF bilan o'tkazing va maqsadlarga ajrating:
$shifrKaliti = hash_hkdf('sha256', $xomSir, 32, 'sessiya-shifr-v1');
$macKaliti = hash_hkdf('sha256', $xomSir, 32, 'sessiya-mac-v1');

korsat('shifr kaliti', bin2hex($shifrKaliti));
korsat('mac kaliti', bin2hex($macKaliti));

final class Sessiya
{
    private readonly string $kalit;

    public function __construct(string $ochiqKalit, string $maxfiyKalit)
    {
        $maxfiy = openssl_pkey_get_private($maxfiyKalit);
        if ($maxfiy === false) {
            throw new RuntimeException('maxfiy kalit oqilmadi');
        }

        $xom = openssl_pkey_derive($ochiqKalit, $maxfiy, 32);
        if ($xom === false) {
            throw new RuntimeException('umumiy sir hisoblanmadi');
        }

        $this->kalit = hash_hkdf('sha256', $xom, 32, 'sessiya-v1');
    }

    public function barmoqIzi(): string
    {
        return substr(bin2hex(hash('sha256', $this->kalit, true)), 0, 16);
    }

    public function shifrla(string $matn): string
    {
        $nonce = random_bytes(12);
        $teg = '';
        $shifr = openssl_encrypt($matn, 'aes-256-gcm', $this->kalit,
            OPENSSL_RAW_DATA, $nonce, $teg);

        return $nonce . $teg . $shifr;
    }

    public function och(string $paket): string
    {
        $matn = openssl_decrypt(substr($paket, 28), 'aes-256-gcm',
            $this->kalit, OPENSSL_RAW_DATA,
            substr($paket, 0, 12), substr($paket, 12, 16));

        if ($matn === false) {
            throw new RuntimeException('ochib bolmadi');
        }

        return $matn;
    }
}

$alisa = new Sessiya(BOBUR_OCHIQ, ALISA_MAXFIY);
$bobur = new Sessiya(ALISA_OCHIQ, BOBUR_MAXFIY);

korsat('Alisa kaliti', $alisa->barmoqIzi());
korsat('Bobur kaliti', $bobur->barmoqIzi());

// Alisa shifrlaydi, Bobur ochadi
$paket = $alisa->shifrla('Uchrashuv ertaga soat 10:00');
korsat('Bobur oqidi', $bobur->och($paket));

// Bobur javob beradi
$javob = $bobur->shifrla('Kelishdik');
korsat('Alisa oqidi', $alisa->och($javob));

// Hujumchining o'z kalit jufti
$hujumMaxfiy = <<<'PEM'
-----BEGIN EC PRIVATE KEY-----
MHcCAQEEIAg//U7lDWR+ujaZDQsoUa9SYA6G2Carjfn3jKfaDxPzoAoGCCqGSM49
AwEHoUQDQgAELnAcXHNotq7eBO+aiXOMCZmHm+mmpw9BJWbDjLgSUSQleE6u/0lk
GQ4rZZHVrXkkes8T3yW3cfMrAnbAkuR5ZQ==
-----END EC PRIVATE KEY-----
PEM;

$hujumOchiq = <<<'PEM'
-----BEGIN PUBLIC KEY-----
MFkwEwYHKoZIzj0CAQYIKoZIzj0DAQcDQgAELnAcXHNotq7eBO+aiXOMCZmHm+mm
pw9BJWbDjLgSUSQleE6u/0lkGQ4rZZHVrXkkes8T3yW3cfMrAnbAkuR5ZQ==
-----END PUBLIC KEY-----
PEM;

// Hujumchi Alisaga o'z kalitini "Boburniki" deb beradi
$alisa = new Sessiya($hujumOchiq, ALISA_MAXFIY);
$hujumAlisaBilan = new Sessiya(ALISA_OCHIQ, $hujumMaxfiy);

// Va Boburga ham o'z kalitini "Alisaniki" deb beradi
$bobur = new Sessiya($hujumOchiq, BOBUR_MAXFIY);
$hujumBoburBilan = new Sessiya(BOBUR_OCHIQ, $hujumMaxfiy);

korsat('Alisa <-> hujumchi', $alisa->barmoqIzi());
korsat('hujumchi <-> Alisa', $hujumAlisaBilan->barmoqIzi());
korsat('Bobur <-> hujumchi', $bobur->barmoqIzi());
korsat('hujumchi <-> Bobur', $hujumBoburBilan->barmoqIzi());

$hujumMaxfiy = <<<'PEM'
-----BEGIN EC PRIVATE KEY-----
MHcCAQEEIAg//U7lDWR+ujaZDQsoUa9SYA6G2Carjfn3jKfaDxPzoAoGCCqGSM49
AwEHoUQDQgAELnAcXHNotq7eBO+aiXOMCZmHm+mmpw9BJWbDjLgSUSQleE6u/0lk
GQ4rZZHVrXkkes8T3yW3cfMrAnbAkuR5ZQ==
-----END EC PRIVATE KEY-----
PEM;

$hujumOchiq = <<<'PEM'
-----BEGIN PUBLIC KEY-----
MFkwEwYHKoZIzj0CAQYIKoZIzj0DAQcDQgAELnAcXHNotq7eBO+aiXOMCZmHm+mm
pw9BJWbDjLgSUSQleE6u/0lkGQ4rZZHVrXkkes8T3yW3cfMrAnbAkuR5ZQ==
-----END PUBLIC KEY-----
PEM;

$alisa = new Sessiya($hujumOchiq, ALISA_MAXFIY);
$hujumAlisaBilan = new Sessiya(ALISA_OCHIQ, $hujumMaxfiy);
$bobur = new Sessiya($hujumOchiq, BOBUR_MAXFIY);
$hujumBoburBilan = new Sessiya(BOBUR_OCHIQ, $hujumMaxfiy);

// 1. Alisa Boburga yozadi (deb o'ylaydi)
$paket = $alisa->shifrla('Hisobga 1000000 som otkaz');

// 2. Hujumchi uni ochadi
$oqilgan = $hujumAlisaBilan->och($paket);
korsat('hujumchi oqidi', $oqilgan);

// 3. Hujumchi o'zgartiradi va Boburga qayta shifrlab yuboradi
$soxta = str_replace('1000000', '9000000', $oqilgan);
$yangiPaket = $hujumBoburBilan->shifrla($soxta);

// 4. Bobur ochadi - hech narsa sezmaydi
korsat('Bobur oqidi', $bobur->och($yangiPaket));

function barmoqIzi(string $ochiqKalit): string
{
    // PEM sarlavhalarini olib tashlaymiz, faqat kalit baytlari qoladi
    $baytlar = base64_decode(preg_replace('/-----[^-]+-----|\s+/', '',
        $ochiqKalit));

    $xesh = hash('sha256', $baytlar, true);

    // odam o'qiy oladigan shakl
    return implode(' ', str_split(strtoupper(
        substr(bin2hex($xesh), 0, 24)), 4));
}

korsat('Alisa', barmoqIzi(ALISA_OCHIQ));
korsat('Bobur', barmoqIzi(BOBUR_OCHIQ));

// PHP da mavjud egri chiziqlar
$egrilar = openssl_get_curve_names();

echo 'jami egri chiziqlar: ', count($egrilar), PHP_EOL;

foreach (['prime256v1', 'secp384r1', 'secp521r1'] as $e) {
    printf('%-12s %s%s', $e,
        in_array($e, $egrilar, true) ? 'mavjud' : 'yoq', PHP_EOL);
}