diff --git a/phpseclib/Crypt/Common/AsymmetricKey.php b/phpseclib/Crypt/Common/AsymmetricKey.php
index a261dfc4..407f0369 100644
--- a/phpseclib/Crypt/Common/AsymmetricKey.php
+++ b/phpseclib/Crypt/Common/AsymmetricKey.php
@@ -136,6 +136,11 @@ abstract class AsymmetricKey
     {
         self::initialize_static_variables();
 
+        $class = new \ReflectionClass(static::class);
+        if ($class->isFinal()) {
+            throw new \RuntimeException('load() should not be called from final classes (' . static::class . ')');
+        }
+
         $components = false;
         foreach (self::$plugins[static::ALGORITHM]['Keys'] as $format) {
             if (isset(self::$invisiblePlugins[static::ALGORITHM]) && in_array($format, self::$invisiblePlugins[static::ALGORITHM])) {
diff --git a/phpseclib/Crypt/DH.php b/phpseclib/Crypt/DH.php
index 876cdbf8..e1deaf08 100644
--- a/phpseclib/Crypt/DH.php
+++ b/phpseclib/Crypt/DH.php
@@ -81,6 +81,11 @@ abstract class DH extends AsymmetricKey
      */
     public static function createParameters(...$args)
     {
+        $class = new \ReflectionClass(static::class);
+        if ($class->isFinal()) {
+            throw new \RuntimeException('createParameters() should not be called from final classes (' . static::class . ')');
+        }
+
         $params = new Parameters();
         if (count($args) == 2 && $args[0] instanceof BigInteger && $args[1] instanceof BigInteger) {
             //if (!$args[0]->isPrime()) {
@@ -242,6 +247,11 @@ abstract class DH extends AsymmetricKey
      */
     public static function createKey(Parameters $params, $length = 0)
     {
+        $class = new \ReflectionClass(static::class);
+        if ($class->isFinal()) {
+            throw new \RuntimeException('createKey() should not be called from final classes (' . static::class . ')');
+        }
+
         $one = new BigInteger(1);
         if ($length) {
             $max = $one->bitwise_leftShift($length);
@@ -387,9 +397,9 @@ abstract class DH extends AsymmetricKey
      */
     public function getParameters()
     {
-        $type = self::validatePlugin('Keys', 'PKCS1', 'saveParameters');
+        $type = DH::validatePlugin('Keys', 'PKCS1', 'saveParameters');
 
         $key = $type::saveParameters($this->prime, $this->base);
-        return self::load($key, 'PKCS1');
+        return DH::load($key, 'PKCS1');
     }
 }
diff --git a/phpseclib/Crypt/DH/Parameters.php b/phpseclib/Crypt/DH/Parameters.php
index e4c15576..c0ded84c 100644
--- a/phpseclib/Crypt/DH/Parameters.php
+++ b/phpseclib/Crypt/DH/Parameters.php
@@ -18,7 +18,7 @@ use phpseclib3\Crypt\DH;
  *
  * @author  Jim Wigginton <terrafrost@php.net>
  */
-class Parameters extends DH
+final class Parameters extends DH
 {
     /**
      * Returns the parameters
diff --git a/phpseclib/Crypt/DH/PrivateKey.php b/phpseclib/Crypt/DH/PrivateKey.php
index fe03452c..737781f8 100644
--- a/phpseclib/Crypt/DH/PrivateKey.php
+++ b/phpseclib/Crypt/DH/PrivateKey.php
@@ -19,7 +19,7 @@ use phpseclib3\Crypt\DH;
  *
  * @author  Jim Wigginton <terrafrost@php.net>
  */
-class PrivateKey extends DH
+final class PrivateKey extends DH
 {
     use Common\Traits\PasswordProtected;
 
diff --git a/phpseclib/Crypt/DH/PublicKey.php b/phpseclib/Crypt/DH/PublicKey.php
index 3536360c..87726a5a 100644
--- a/phpseclib/Crypt/DH/PublicKey.php
+++ b/phpseclib/Crypt/DH/PublicKey.php
@@ -19,7 +19,7 @@ use phpseclib3\Crypt\DH;
  *
  * @author  Jim Wigginton <terrafrost@php.net>
  */
-class PublicKey extends DH
+final class PublicKey extends DH
 {
     use Common\Traits\Fingerprint;
 
diff --git a/phpseclib/Crypt/DSA.php b/phpseclib/Crypt/DSA.php
index 1d265860..0123c66c 100644
--- a/phpseclib/Crypt/DSA.php
+++ b/phpseclib/Crypt/DSA.php
@@ -105,6 +105,11 @@ abstract class DSA extends AsymmetricKey
     {
         self::initialize_static_variables();
 
+        $class = new \ReflectionClass(static::class);
+        if ($class->isFinal()) {
+            throw new \RuntimeException('createParameters() should not be called from final classes (' . static::class . ')');
+        }
+
         if (!isset(self::$engines['PHP'])) {
             self::useBestEngine();
         }
@@ -180,6 +185,11 @@ abstract class DSA extends AsymmetricKey
     {
         self::initialize_static_variables();
 
+        $class = new \ReflectionClass(static::class);
+        if ($class->isFinal()) {
+            throw new \RuntimeException('createKey() should not be called from final classes (' . static::class . ')');
+        }
+
         if (!isset(self::$engines['PHP'])) {
             self::useBestEngine();
         }
diff --git a/phpseclib/Crypt/DSA/Parameters.php b/phpseclib/Crypt/DSA/Parameters.php
index 6bcb152d..84d16ba6 100644
--- a/phpseclib/Crypt/DSA/Parameters.php
+++ b/phpseclib/Crypt/DSA/Parameters.php
@@ -18,7 +18,7 @@ use phpseclib3\Crypt\DSA;
  *
  * @author  Jim Wigginton <terrafrost@php.net>
  */
-class Parameters extends DSA
+final class Parameters extends DSA
 {
     /**
      * Returns the parameters
diff --git a/phpseclib/Crypt/DSA/PrivateKey.php b/phpseclib/Crypt/DSA/PrivateKey.php
index 7039941b..74d3e69e 100644
--- a/phpseclib/Crypt/DSA/PrivateKey.php
+++ b/phpseclib/Crypt/DSA/PrivateKey.php
@@ -21,7 +21,7 @@ use phpseclib3\Math\BigInteger;
  *
  * @author  Jim Wigginton <terrafrost@php.net>
  */
-class PrivateKey extends DSA implements Common\PrivateKey
+final class PrivateKey extends DSA implements Common\PrivateKey
 {
     use Common\Traits\PasswordProtected;
 
diff --git a/phpseclib/Crypt/DSA/PublicKey.php b/phpseclib/Crypt/DSA/PublicKey.php
index 7e00e24a..c14ffbdf 100644
--- a/phpseclib/Crypt/DSA/PublicKey.php
+++ b/phpseclib/Crypt/DSA/PublicKey.php
@@ -20,7 +20,7 @@ use phpseclib3\Crypt\DSA\Formats\Signature\ASN1 as ASN1Signature;
  *
  * @author  Jim Wigginton <terrafrost@php.net>
  */
-class PublicKey extends DSA implements Common\PublicKey
+final class PublicKey extends DSA implements Common\PublicKey
 {
     use Common\Traits\Fingerprint;
 
diff --git a/phpseclib/Crypt/EC.php b/phpseclib/Crypt/EC.php
index e61f0092..10b38254 100644
--- a/phpseclib/Crypt/EC.php
+++ b/phpseclib/Crypt/EC.php
@@ -140,6 +140,11 @@ abstract class EC extends AsymmetricKey
     {
         self::initialize_static_variables();
 
+        $class = new \ReflectionClass(static::class);
+        if ($class->isFinal()) {
+            throw new \RuntimeException('createKey() should not be called from final classes (' . static::class . ')');
+        }
+
         if (!isset(self::$engines['PHP'])) {
             self::useBestEngine();
         }
diff --git a/phpseclib/Crypt/EC/Parameters.php b/phpseclib/Crypt/EC/Parameters.php
index c9bf1bea..c0ed64a8 100644
--- a/phpseclib/Crypt/EC/Parameters.php
+++ b/phpseclib/Crypt/EC/Parameters.php
@@ -18,7 +18,7 @@ use phpseclib3\Crypt\EC;
  *
  * @author  Jim Wigginton <terrafrost@php.net>
  */
-class Parameters extends EC
+final class Parameters extends EC
 {
     /**
      * Returns the parameters
diff --git a/phpseclib/Crypt/EC/PrivateKey.php b/phpseclib/Crypt/EC/PrivateKey.php
index 8bf86862..462ea1a3 100644
--- a/phpseclib/Crypt/EC/PrivateKey.php
+++ b/phpseclib/Crypt/EC/PrivateKey.php
@@ -29,7 +29,7 @@ use phpseclib3\Math\BigInteger;
  *
  * @author  Jim Wigginton <terrafrost@php.net>
  */
-class PrivateKey extends EC implements Common\PrivateKey
+final class PrivateKey extends EC implements Common\PrivateKey
 {
     use Common\Traits\PasswordProtected;
 
diff --git a/phpseclib/Crypt/EC/PublicKey.php b/phpseclib/Crypt/EC/PublicKey.php
index 609d5960..4558ce34 100644
--- a/phpseclib/Crypt/EC/PublicKey.php
+++ b/phpseclib/Crypt/EC/PublicKey.php
@@ -28,7 +28,7 @@ use phpseclib3\Math\BigInteger;
  *
  * @author  Jim Wigginton <terrafrost@php.net>
  */
-class PublicKey extends EC implements Common\PublicKey
+final class PublicKey extends EC implements Common\PublicKey
 {
     use Common\Traits\Fingerprint;
 
diff --git a/phpseclib/Crypt/RSA.php b/phpseclib/Crypt/RSA.php
index 207a9051..7b935cc2 100644
--- a/phpseclib/Crypt/RSA.php
+++ b/phpseclib/Crypt/RSA.php
@@ -304,6 +304,11 @@ abstract class RSA extends AsymmetricKey
     {
         self::initialize_static_variables();
 
+        $class = new \ReflectionClass(static::class);
+        if ($class->isFinal()) {
+            throw new \RuntimeException('createKey() should not be called from final classes (' . static::class . ')');
+        }
+
         $regSize = $bits >> 1; // divide by two to see how many bits P and Q would be
         if ($regSize > self::$smallestPrime) {
             $num_primes = floor($bits / self::$smallestPrime);
diff --git a/phpseclib/Crypt/RSA/PrivateKey.php b/phpseclib/Crypt/RSA/PrivateKey.php
index 84cede8e..37dd09a4 100644
--- a/phpseclib/Crypt/RSA/PrivateKey.php
+++ b/phpseclib/Crypt/RSA/PrivateKey.php
@@ -23,7 +23,7 @@ use phpseclib3\Math\BigInteger;
  *
  * @author  Jim Wigginton <terrafrost@php.net>
  */
-class PrivateKey extends RSA implements Common\PrivateKey
+final class PrivateKey extends RSA implements Common\PrivateKey
 {
     use Common\Traits\PasswordProtected;
 
diff --git a/phpseclib/Crypt/RSA/PublicKey.php b/phpseclib/Crypt/RSA/PublicKey.php
index 89408792..58939a9f 100644
--- a/phpseclib/Crypt/RSA/PublicKey.php
+++ b/phpseclib/Crypt/RSA/PublicKey.php
@@ -28,7 +28,7 @@ use phpseclib3\Math\BigInteger;
  *
  * @author  Jim Wigginton <terrafrost@php.net>
  */
-class PublicKey extends RSA implements Common\PublicKey
+final class PublicKey extends RSA implements Common\PublicKey
 {
     use Common\Traits\Fingerprint;