Added support for absent parameters field in PSS keys

See [here](https://tools.ietf.org/html/rfc4055#section-3.1) for details.

phpseclib/Crypt/RSA/Formats/Keys/PSS.php

@@ -120,11 +120,16 @@ abstract class PSS extends Progenitor
 
         $result = $components + PKCS1::load($key[$type . 'Key']);
 
-        $decoded = ASN1::decodeBER($key[$type . 'KeyAlgorithm']['parameters']);
-        if ($decoded === false) {
-            throw new \UnexpectedValueException('Unable to decode parameters');
+        if (isset($key[$type . 'KeyAlgorithm']['parameters'])) {
+            $decoded = ASN1::decodeBER($key[$type . 'KeyAlgorithm']['parameters']);
+            if ($decoded === false) {
+                throw new \UnexpectedValueException('Unable to decode parameters');
+            }
+            $params = ASN1::asn1map($decoded[0], Maps\RSASSA_PSS_params::MAP);
+        } else {
+            $params = [];
         }
-        $params = ASN1::asn1map($decoded[0], Maps\RSASSA_PSS_params::MAP);
+
         if (isset($params['maskGenAlgorithm']['parameters'])) {
             $decoded = ASN1::decodeBER($params['maskGenAlgorithm']['parameters']);
             if ($decoded === false) {
@@ -144,7 +149,9 @@ abstract class PSS extends Progenitor
 
         $result['hash'] = str_replace('id-', '', $params['hashAlgorithm']['algorithm']);
         $result['MGFHash'] = str_replace('id-', '', $params['maskGenAlgorithm']['parameters']['algorithm']);
-        $result['saltLength'] = (int) $params['saltLength']->toString();
+        if (isset($params['saltLength'])) {
+            $result['saltLength'] = (int) $params['saltLength']->toString();
+        }
 
         if (isset($key['meta'])) {
             $result['meta'] = $key['meta'];

tests/Unit/Crypt/RSA/LoadKeyTest.php

@@ -246,6 +246,66 @@ ZQIDAQAB
         $this->assertInstanceOf(PublicKey::class, $rsa);
     }
 
+
+    public function testPubKeyPssWithoutParams()
+    {
+        // extracted from a SubjectPublicKeyInfo of a CSR created by OpenSSL
+        $key = '-----BEGIN PUBLIC KEY-----
+MIIBIDALBgkqhkiG9w0BAQoDggEPADCCAQoCggEBANHPPf5tjTmEHtQvzi6+rItj
+G3OUvh6Nihc9bXSu0xNFjl/9TdyIXstRUG/Lh07isHgZFEfXn4pmm/iZIQh09ACg
+TjEau8rpcLB0BS9dDgTh8hvgkbdxWR2UPxk34bFcdgIplckslAfB4+/ebL+ObvUa
+W3sZosTq3D6/qh0fujGZg/EKLJcNCHI27XMiAT5yWztSjHWwQm7LBwJ5uKlFLEDC
+Z/+LIV/vPEIMfE6lA/+OnLKwVFB540eXQPuWar1ARHXN8PpiCqJHanddYMA5l/Cw
+5R7kJ+CBoHzaPePXjB9V1bfzEBzBHb2ddiSjum+qtLWuH0Q7B8gPX9EjxIwuCzMC
+AwEAAQ==
+-----END PUBLIC KEY-----';
+        $key = str_replace(["\r", "\n", "\r\n"], ' ', $key);
+
+        $rsa = PublicKeyLoader::load($key);
+
+        $this->assertInstanceOf(PublicKey::class, $rsa);
+        $this->assertIsString("$rsa");
+    }
+
+    public function testPrivateKeyPssWithoutParams()
+    {
+        $key = '-----BEGIN PRIVATE KEY-----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+-----END PRIVATE KEY-----';
+
+        $key = str_replace(["\r", "\n", "\r\n"], ' ', $key);
+
+        $rsa = PublicKeyLoader::load($key);
+
+        $this->assertInstanceOf(PrivateKey::class, $rsa);
+        $this->assertIsString("$rsa");
+    }
+
     public function testPubPrivateKey()
     {
         $key = '-----BEGIN RSA PUBLIC KEY-----