diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 19dd4559..03683f97 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -51,7 +51,7 @@ jobs:
                 with:
                     php-version: ${{ matrix.php-version }}
             -   name: Composer Install
-                run: composer install --classmap-authoritative --no-interaction --no-cache
+                run: composer install --classmap-authoritative --no-interaction --no-cache --ignore-platform-req=php
             -   name: Setup Secure Shell Functional Tests
                 if: matrix.os == 'ubuntu-latest'
                 run: |
@@ -80,4 +80,4 @@ jobs:
             fail-fast: false
             matrix:
                 os: [ubuntu-latest, windows-latest, macos-latest]
-                php-version: ['8.2']
+                php-version: ['8.1', '8.2']
diff --git a/phpseclib/Crypt/Common/SymmetricKey.php b/phpseclib/Crypt/Common/SymmetricKey.php
index a7724762..cae9e15d 100644
--- a/phpseclib/Crypt/Common/SymmetricKey.php
+++ b/phpseclib/Crypt/Common/SymmetricKey.php
@@ -268,85 +268,6 @@ abstract class SymmetricKey
      */
     protected $debuffer;
 
-    /**
-     * mcrypt resource for encryption
-     *
-     * The mcrypt resource can be recreated every time something needs to be created or it can be created just once.
-     * Since mcrypt operates in continuous mode, by default, it'll need to be recreated when in non-continuous mode.
-     *
-     * @see self::encrypt()
-     * @var resource
-     */
-    private $enmcrypt;
-
-    /**
-     * mcrypt resource for decryption
-     *
-     * The mcrypt resource can be recreated every time something needs to be created or it can be created just once.
-     * Since mcrypt operates in continuous mode, by default, it'll need to be recreated when in non-continuous mode.
-     *
-     * @see self::decrypt()
-     * @var resource
-     */
-    private $demcrypt;
-
-    /**
-     * Does the enmcrypt resource need to be (re)initialized?
-     *
-     * @see \phpseclib3\Crypt\Twofish::setKey()
-     * @see \phpseclib3\Crypt\Twofish::setIV()
-     * @var bool
-     */
-    private $enchanged = true;
-
-    /**
-     * Does the demcrypt resource need to be (re)initialized?
-     *
-     * @see \phpseclib3\Crypt\Twofish::setKey()
-     * @see \phpseclib3\Crypt\Twofish::setIV()
-     * @var bool
-     */
-    private $dechanged = true;
-
-    /**
-     * mcrypt resource for CFB mode
-     *
-     * mcrypt's CFB mode, in (and only in) buffered context,
-     * is broken, so phpseclib implements the CFB mode by it self,
-     * even when the mcrypt php extension is available.
-     *
-     * In order to do the CFB-mode work (fast) phpseclib
-     * use a separate ECB-mode mcrypt resource.
-     *
-     * @link http://phpseclib.sourceforge.net/cfb-demo.phps
-     * @see self::encrypt()
-     * @see self::decrypt()
-     * @see self::setupMcrypt()
-     * @var resource
-     */
-    private $ecb;
-
-    /**
-     * Optimizing value while CFB-encrypting
-     *
-     * Only relevant if $continuousBuffer enabled
-     * and $engine == self::ENGINE_MCRYPT
-     *
-     * It's faster to re-init $enmcrypt if
-     * $buffer bytes > $cfb_init_len than
-     * using the $ecb resource furthermore.
-     *
-     * This value depends of the chosen cipher
-     * and the time it would be needed for it's
-     * initialization [by mcrypt_generic_init()]
-     * which, typically, depends on the complexity
-     * on its internaly Key-expanding algorithm.
-     *
-     * @see self::encrypt()
-     * @var int
-     */
-    protected $cfb_init_len = 600;
-
     /**
      * Does internal cipher state need to be (re)initialized?
      *
diff --git a/phpseclib/Crypt/DH.php b/phpseclib/Crypt/DH.php
index 90897591..a7565ff5 100644
--- a/phpseclib/Crypt/DH.php
+++ b/phpseclib/Crypt/DH.php
@@ -64,6 +64,11 @@ abstract class DH extends AsymmetricKey
      */
     protected $base;
 
+    /**
+     * @var BigInteger
+     */
+    protected $publicKey;
+
     /**
      * Create DH parameters
      *
diff --git a/phpseclib/Crypt/DH/PublicKey.php b/phpseclib/Crypt/DH/PublicKey.php
index 583b3b2e..7ffd6fab 100644
--- a/phpseclib/Crypt/DH/PublicKey.php
+++ b/phpseclib/Crypt/DH/PublicKey.php
@@ -26,13 +26,6 @@ class PublicKey extends DH
 {
     use Common\Traits\Fingerprint;
 
-    /**
-     * Public Key
-     *
-     * @var BigInteger
-     */
-    protected $publicKey;
-
     /**
      * Returns the public key
      *
diff --git a/phpseclib/Crypt/EC/BaseCurves/KoblitzPrime.php b/phpseclib/Crypt/EC/BaseCurves/KoblitzPrime.php
index 4454dcc6..b22ba469 100644
--- a/phpseclib/Crypt/EC/BaseCurves/KoblitzPrime.php
+++ b/phpseclib/Crypt/EC/BaseCurves/KoblitzPrime.php
@@ -41,7 +41,7 @@ use phpseclib3\Math\PrimeField;
 class KoblitzPrime extends Prime
 {
     /**
-     * @var array<array<string,BigInteger>>
+     * @var list<array{a: BigInteger, b: BigInteger}>
      */
     public $basis = [];