diff --git a/src/Symfony/Component/Security/Core/Encoder/BasePasswordEncoder.php b/src/Symfony/Component/Security/Core/Encoder/BasePasswordEncoder.php
index ffacede722c9..4c5824f783c3 100644
--- a/src/Symfony/Component/Security/Core/Encoder/BasePasswordEncoder.php
+++ b/src/Symfony/Component/Security/Core/Encoder/BasePasswordEncoder.php
@@ -31,11 +31,9 @@ public function needsRehash(string $encoded): bool
     /**
      * Demerges a merge password and salt string.
      *
-     * @param string $mergedPasswordSalt The merged password and salt string
-     *
      * @return array An array where the first element is the password and the second the salt
      */
-    protected function demergePasswordAndSalt($mergedPasswordSalt)
+    protected function demergePasswordAndSalt(string $mergedPasswordSalt)
     {
         if (empty($mergedPasswordSalt)) {
             return ['', ''];
@@ -56,14 +54,11 @@ protected function demergePasswordAndSalt($mergedPasswordSalt)
     /**
      * Merges a password and a salt.
      *
-     * @param string      $password The password to be used
-     * @param string|null $salt     The salt to be used
-     *
      * @return string a merged password and salt
      *
      * @throws \InvalidArgumentException
      */
-    protected function mergePasswordAndSalt($password, $salt)
+    protected function mergePasswordAndSalt(string $password, ?string $salt)
     {
         if (empty($salt)) {
             return $password;
@@ -82,12 +77,9 @@ protected function mergePasswordAndSalt($password, $salt)
      * This method implements a constant-time algorithm to compare passwords to
      * avoid (remote) timing attacks.
      *
-     * @param string $password1 The first password
-     * @param string $password2 The second password
-     *
      * @return bool true if the two passwords are the same, false otherwise
      */
-    protected function comparePasswords($password1, $password2)
+    protected function comparePasswords(string $password1, string $password2)
     {
         return hash_equals($password1, $password2);
     }
@@ -95,11 +87,9 @@ protected function comparePasswords($password1, $password2)
     /**
      * Checks if the password is too long.
      *
-     * @param string $password The password to check
-     *
      * @return bool true if the password is too long, false otherwise
      */
-    protected function isPasswordTooLong($password)
+    protected function isPasswordTooLong(string $password)
     {
         return \strlen($password) > static::MAX_PASSWORD_LENGTH;
     }
diff --git a/src/Symfony/Component/Security/Core/Encoder/MessageDigestPasswordEncoder.php b/src/Symfony/Component/Security/Core/Encoder/MessageDigestPasswordEncoder.php
index dba0c30d5a9d..88ce73007ec3 100644
--- a/src/Symfony/Component/Security/Core/Encoder/MessageDigestPasswordEncoder.php
+++ b/src/Symfony/Component/Security/Core/Encoder/MessageDigestPasswordEncoder.php
@@ -39,7 +39,7 @@ public function __construct(string $algorithm = 'sha512', bool $encodeHashAsBase
     /**
      * {@inheritdoc}
      */
-    public function encodePassword($raw, $salt)
+    public function encodePassword(string $raw, ?string $salt)
     {
         if ($this->isPasswordTooLong($raw)) {
             throw new BadCredentialsException('Invalid password.');
@@ -63,7 +63,7 @@ public function encodePassword($raw, $salt)
     /**
      * {@inheritdoc}
      */
-    public function isPasswordValid($encoded, $raw, $salt)
+    public function isPasswordValid(string $encoded, string $raw, ?string $salt)
     {
         return !$this->isPasswordTooLong($raw) && $this->comparePasswords($encoded, $this->encodePassword($raw, $salt));
     }
diff --git a/src/Symfony/Component/Security/Core/Encoder/MigratingPasswordEncoder.php b/src/Symfony/Component/Security/Core/Encoder/MigratingPasswordEncoder.php
index 2c8a6f72ce9a..cd10b32bf733 100644
--- a/src/Symfony/Component/Security/Core/Encoder/MigratingPasswordEncoder.php
+++ b/src/Symfony/Component/Security/Core/Encoder/MigratingPasswordEncoder.php
@@ -34,7 +34,7 @@ public function __construct(PasswordEncoderInterface $bestEncoder, PasswordEncod
     /**
      * {@inheritdoc}
      */
-    public function encodePassword($raw, $salt): string
+    public function encodePassword(string $raw, ?string $salt): string
     {
         return $this->bestEncoder->encodePassword($raw, $salt);
     }
@@ -42,7 +42,7 @@ public function encodePassword($raw, $salt): string
     /**
      * {@inheritdoc}
      */
-    public function isPasswordValid($encoded, $raw, $salt): bool
+    public function isPasswordValid(string $encoded, string $raw, ?string $salt): bool
     {
         if ($this->bestEncoder->isPasswordValid($encoded, $raw, $salt)) {
             return true;
diff --git a/src/Symfony/Component/Security/Core/Encoder/NativePasswordEncoder.php b/src/Symfony/Component/Security/Core/Encoder/NativePasswordEncoder.php
index 51a17b93cf5f..a7612a595e37 100644
--- a/src/Symfony/Component/Security/Core/Encoder/NativePasswordEncoder.php
+++ b/src/Symfony/Component/Security/Core/Encoder/NativePasswordEncoder.php
@@ -57,7 +57,7 @@ public function __construct(int $opsLimit = null, int $memLimit = null, int $cos
     /**
      * {@inheritdoc}
      */
-    public function encodePassword($raw, $salt)
+    public function encodePassword(string $raw, ?string $salt)
     {
         if (\strlen($raw) > self::MAX_PASSWORD_LENGTH) {
             throw new BadCredentialsException('Invalid password.');
@@ -78,7 +78,7 @@ public function encodePassword($raw, $salt)
     /**
      * {@inheritdoc}
      */
-    public function isPasswordValid($encoded, $raw, $salt): bool
+    public function isPasswordValid(string $encoded, string $raw, ?string $salt): bool
     {
         if (72 < \strlen($raw) && 0 === strpos($encoded, '$2')) {
             // BCrypt encodes only the first 72 chars
diff --git a/src/Symfony/Component/Security/Core/Encoder/PasswordEncoderInterface.php b/src/Symfony/Component/Security/Core/Encoder/PasswordEncoderInterface.php
index 07341588d222..9d8d48f8db43 100644
--- a/src/Symfony/Component/Security/Core/Encoder/PasswordEncoderInterface.php
+++ b/src/Symfony/Component/Security/Core/Encoder/PasswordEncoderInterface.php
@@ -23,15 +23,12 @@ interface PasswordEncoderInterface
     /**
      * Encodes the raw password.
      *
-     * @param string      $raw  The password to encode
-     * @param string|null $salt The salt
-     *
      * @return string The encoded password
      *
      * @throws BadCredentialsException   If the raw password is invalid, e.g. excessively long
      * @throws \InvalidArgumentException If the salt is invalid
      */
-    public function encodePassword($raw, $salt);
+    public function encodePassword(string $raw, ?string $salt);
 
     /**
      * Checks a raw password against an encoded password.
@@ -44,7 +41,7 @@ public function encodePassword($raw, $salt);
      *
      * @throws \InvalidArgumentException If the salt is invalid
      */
-    public function isPasswordValid($encoded, $raw, $salt);
+    public function isPasswordValid(string $encoded, string $raw, ?string $salt);
 
     /**
      * Checks if an encoded password would benefit from rehashing.
diff --git a/src/Symfony/Component/Security/Core/Encoder/Pbkdf2PasswordEncoder.php b/src/Symfony/Component/Security/Core/Encoder/Pbkdf2PasswordEncoder.php
index 4c4eee75d807..c53abaad5ab1 100644
--- a/src/Symfony/Component/Security/Core/Encoder/Pbkdf2PasswordEncoder.php
+++ b/src/Symfony/Component/Security/Core/Encoder/Pbkdf2PasswordEncoder.php
@@ -52,7 +52,7 @@ public function __construct(string $algorithm = 'sha512', bool $encodeHashAsBase
      *
      * @throws \LogicException when the algorithm is not supported
      */
-    public function encodePassword($raw, $salt)
+    public function encodePassword(string $raw, ?string $salt)
     {
         if ($this->isPasswordTooLong($raw)) {
             throw new BadCredentialsException('Invalid password.');
@@ -70,7 +70,7 @@ public function encodePassword($raw, $salt)
     /**
      * {@inheritdoc}
      */
-    public function isPasswordValid($encoded, $raw, $salt)
+    public function isPasswordValid(string $encoded, string $raw, ?string $salt)
     {
         return !$this->isPasswordTooLong($raw) && $this->comparePasswords($encoded, $this->encodePassword($raw, $salt));
     }
diff --git a/src/Symfony/Component/Security/Core/Encoder/PlaintextPasswordEncoder.php b/src/Symfony/Component/Security/Core/Encoder/PlaintextPasswordEncoder.php
index a9347f7257fa..64353c29fae9 100644
--- a/src/Symfony/Component/Security/Core/Encoder/PlaintextPasswordEncoder.php
+++ b/src/Symfony/Component/Security/Core/Encoder/PlaintextPasswordEncoder.php
@@ -33,7 +33,7 @@ public function __construct(bool $ignorePasswordCase = false)
     /**
      * {@inheritdoc}
      */
-    public function encodePassword($raw, $salt)
+    public function encodePassword(string $raw, ?string $salt)
     {
         if ($this->isPasswordTooLong($raw)) {
             throw new BadCredentialsException('Invalid password.');
@@ -45,7 +45,7 @@ public function encodePassword($raw, $salt)
     /**
      * {@inheritdoc}
      */
-    public function isPasswordValid($encoded, $raw, $salt)
+    public function isPasswordValid(string $encoded, string $raw, ?string $salt)
     {
         if ($this->isPasswordTooLong($raw)) {
             return false;
diff --git a/src/Symfony/Component/Security/Core/Encoder/SodiumPasswordEncoder.php b/src/Symfony/Component/Security/Core/Encoder/SodiumPasswordEncoder.php
index 2215a20a2b2e..c55a486b7cab 100644
--- a/src/Symfony/Component/Security/Core/Encoder/SodiumPasswordEncoder.php
+++ b/src/Symfony/Component/Security/Core/Encoder/SodiumPasswordEncoder.php
@@ -54,7 +54,7 @@ public static function isSupported(): bool
     /**
      * {@inheritdoc}
      */
-    public function encodePassword($raw, $salt): string
+    public function encodePassword(string $raw, ?string $salt): string
     {
         if (\strlen($raw) > self::MAX_PASSWORD_LENGTH) {
             throw new BadCredentialsException('Invalid password.');
@@ -74,7 +74,7 @@ public function encodePassword($raw, $salt): string
     /**
      * {@inheritdoc}
      */
-    public function isPasswordValid($encoded, $raw, $salt): bool
+    public function isPasswordValid(string $encoded, string $raw, ?string $salt): bool
     {
         if (\strlen($raw) > self::MAX_PASSWORD_LENGTH) {
             return false;
diff --git a/src/Symfony/Component/Security/Core/Encoder/UserPasswordEncoder.php b/src/Symfony/Component/Security/Core/Encoder/UserPasswordEncoder.php
index e091cba0e683..dd33f8462c2e 100644
--- a/src/Symfony/Component/Security/Core/Encoder/UserPasswordEncoder.php
+++ b/src/Symfony/Component/Security/Core/Encoder/UserPasswordEncoder.php
@@ -30,7 +30,7 @@ public function __construct(EncoderFactoryInterface $encoderFactory)
     /**
      * {@inheritdoc}
      */
-    public function encodePassword(UserInterface $user, $plainPassword)
+    public function encodePassword(UserInterface $user, string $plainPassword)
     {
         $encoder = $this->encoderFactory->getEncoder($user);
 
@@ -40,7 +40,7 @@ public function encodePassword(UserInterface $user, $plainPassword)
     /**
      * {@inheritdoc}
      */
-    public function isPasswordValid(UserInterface $user, $raw)
+    public function isPasswordValid(UserInterface $user, string $raw)
     {
         $encoder = $this->encoderFactory->getEncoder($user);
 
diff --git a/src/Symfony/Component/Security/Core/Encoder/UserPasswordEncoderInterface.php b/src/Symfony/Component/Security/Core/Encoder/UserPasswordEncoderInterface.php
index 045e529e5c60..fa4ec67815c9 100644
--- a/src/Symfony/Component/Security/Core/Encoder/UserPasswordEncoderInterface.php
+++ b/src/Symfony/Component/Security/Core/Encoder/UserPasswordEncoderInterface.php
@@ -23,20 +23,14 @@ interface UserPasswordEncoderInterface
     /**
      * Encodes the plain password.
      *
-     * @param UserInterface $user          The user
-     * @param string        $plainPassword The password to encode
-     *
      * @return string The encoded password
      */
-    public function encodePassword(UserInterface $user, $plainPassword);
+    public function encodePassword(UserInterface $user, string $plainPassword);
 
     /**
-     * @param UserInterface $user The user
-     * @param string        $raw  A raw password
-     *
      * @return bool true if the password is valid, false otherwise
      */
-    public function isPasswordValid(UserInterface $user, $raw);
+    public function isPasswordValid(UserInterface $user, string $raw);
 
     /**
      * Checks if an encoded password would benefit from rehashing.
diff --git a/src/Symfony/Component/Security/Core/Tests/Authentication/Provider/DaoAuthenticationProviderTest.php b/src/Symfony/Component/Security/Core/Tests/Authentication/Provider/DaoAuthenticationProviderTest.php
index 53ff17055422..d8fa39828358 100644
--- a/src/Symfony/Component/Security/Core/Tests/Authentication/Provider/DaoAuthenticationProviderTest.php
+++ b/src/Symfony/Component/Security/Core/Tests/Authentication/Provider/DaoAuthenticationProviderTest.php
@@ -15,6 +15,7 @@
 use Symfony\Component\Security\Core\Authentication\Provider\DaoAuthenticationProvider;
 use Symfony\Component\Security\Core\Encoder\PlaintextPasswordEncoder;
 use Symfony\Component\Security\Core\Exception\UsernameNotFoundException;
+use Symfony\Component\Security\Core\User\UserInterface;
 
 class DaoAuthenticationProviderTest extends TestCase
 {
@@ -73,7 +74,7 @@ public function testRetrieveUserReturnsUserFromTokenOnReauthentication()
                      ->method('loadUserByUsername')
         ;
 
-        $user = $this->getMockBuilder('Symfony\\Component\\Security\\Core\\User\\UserInterface')->getMock();
+        $user = new TestUser();
         $token = $this->getSupportedToken();
         $token->expects($this->once())
               ->method('getUser')
@@ -90,7 +91,7 @@ public function testRetrieveUserReturnsUserFromTokenOnReauthentication()
 
     public function testRetrieveUser()
     {
-        $user = $this->getMockBuilder('Symfony\\Component\\Security\\Core\\User\\UserInterface')->getMock();
+        $user = new TestUser();
 
         $userProvider = $this->getMockBuilder('Symfony\\Component\\Security\\Core\\User\\UserProviderInterface')->getMock();
         $userProvider->expects($this->once())
@@ -127,11 +128,7 @@ public function testCheckAuthenticationWhenCredentialsAreEmpty()
             ->willReturn('')
         ;
 
-        $method->invoke(
-            $provider,
-            $this->getMockBuilder('Symfony\\Component\\Security\\Core\\User\\UserInterface')->getMock(),
-            $token
-        );
+        $method->invoke($provider, new TestUser(), $token);
     }
 
     public function testCheckAuthenticationWhenCredentialsAre0()
@@ -154,11 +151,7 @@ public function testCheckAuthenticationWhenCredentialsAre0()
             ->willReturn('0')
         ;
 
-        $method->invoke(
-            $provider,
-            $this->getMockBuilder('Symfony\\Component\\Security\\Core\\User\\UserInterface')->getMock(),
-            $token
-        );
+        $method->invoke($provider, new TestUser(), $token);
     }
 
     /**
@@ -182,7 +175,7 @@ public function testCheckAuthenticationWhenCredentialsAreNotValid()
               ->willReturn('foo')
         ;
 
-        $method->invoke($provider, $this->getMockBuilder('Symfony\\Component\\Security\\Core\\User\\UserInterface')->getMock(), $token);
+        $method->invoke($provider, new TestUser(), $token);
     }
 
     /**
@@ -256,7 +249,7 @@ public function testCheckAuthentication()
               ->willReturn('foo')
         ;
 
-        $method->invoke($provider, $this->getMockBuilder('Symfony\\Component\\Security\\Core\\User\\UserInterface')->getMock(), $token);
+        $method->invoke($provider, new TestUser(), $token);
     }
 
     protected function getSupportedToken()
@@ -299,3 +292,30 @@ protected function getProvider($user = null, $userChecker = null, $passwordEncod
         return new DaoAuthenticationProvider($userProvider, $userChecker, 'key', $encoderFactory);
     }
 }
+
+class TestUser implements UserInterface
+{
+    public function getRoles()
+    {
+        return [];
+    }
+
+    public function getPassword()
+    {
+        return 'secret';
+    }
+
+    public function getSalt()
+    {
+        return null;
+    }
+
+    public function getUsername()
+    {
+        return 'jane_doe';
+    }
+
+    public function eraseCredentials()
+    {
+    }
+}