From abb89dbc6efd3370d98991f8bcb9f21950bb2979 Mon Sep 17 00:00:00 2001
From: Benedikt Galbavy <if22b082@technikum-wien.at>
Date: Sun, 5 Oct 2025 14:45:32 +0200
Subject: [PATCH] Finished implementation

---
 .run/PwDemoApplication.run.xml                |   1 -
 .run/Setup tables.run.xml                     |  19 +++
 presentation_notes.md                         |   8 +-
 .../pw_demo/CustomPbkdf2PasswordEncoder.java  | 115 ++++++++++++++
 .../itse/pw_demo/RegistrationController.java  |  38 +++++
 .../itse/pw_demo/SHA256PasswordEncoder.java   |  28 ++++
 .../fhtw/itse/pw_demo/SecurityConfig.java     |  27 ++--
 .../pw_demo/SelectablePasswordEncoder.java    | 144 ++++++++++++++++++
 .../fhtw/itse/pw_demo/UserDTO.java            |  12 ++
 .../fhtw/itse/pw_demo/WelcomeController.java  |   1 -
 src/main/resources/templates/register.html    |  43 ++++++
 11 files changed, 420 insertions(+), 16 deletions(-)
 create mode 100644 .run/Setup tables.run.xml
 create mode 100644 src/main/java/at/nanopenguin/fhtw/itse/pw_demo/CustomPbkdf2PasswordEncoder.java
 create mode 100644 src/main/java/at/nanopenguin/fhtw/itse/pw_demo/RegistrationController.java
 create mode 100644 src/main/java/at/nanopenguin/fhtw/itse/pw_demo/SHA256PasswordEncoder.java
 create mode 100644 src/main/java/at/nanopenguin/fhtw/itse/pw_demo/SelectablePasswordEncoder.java
 create mode 100644 src/main/java/at/nanopenguin/fhtw/itse/pw_demo/UserDTO.java
 create mode 100644 src/main/resources/templates/register.html

diff --git a/.run/PwDemoApplication.run.xml b/.run/PwDemoApplication.run.xml
index 0f957cc..b9bcfe9 100644
--- a/.run/PwDemoApplication.run.xml
+++ b/.run/PwDemoApplication.run.xml
@@ -4,7 +4,6 @@
     <option name="SPRING_BOOT_MAIN_CLASS" value="at.nanopenguin.fhtw.itse.pw_demo.PwDemoApplication" />
     <method v="2">
       <option name="Make" enabled="true" />
-      <option name="RunConfigurationTask" enabled="true" run_configuration_name="Docker Image" run_configuration_type="docker-deploy" />
     </method>
   </configuration>
 </component>
\ No newline at end of file
diff --git a/.run/Setup tables.run.xml b/.run/Setup tables.run.xml
new file mode 100644
index 0000000..1f5966f
--- /dev/null
+++ b/.run/Setup tables.run.xml	
@@ -0,0 +1,19 @@
+<component name="ProjectRunConfigurationManager">
+  <configuration default="false" name="Setup tables" type="DatabaseScript">
+    <data-source id="1c5ced7c-10f3-4662-9fcf-f6601b0cfc94" />
+    <script-text>CREATE TABLE users (
+                       username VARCHAR(50) NOT NULL PRIMARY KEY,
+                       password VARCHAR(500) NOT NULL,
+                       enabled BOOLEAN NOT NULL
+);
+
+CREATE TABLE authorities (
+                             username VARCHAR(50) NOT NULL,
+                             authority VARCHAR(50) NOT NULL,
+                             CONSTRAINT fk_authorities_users FOREIGN KEY (username) REFERENCES users(username)
+);
+
+CREATE UNIQUE INDEX ix_auth_username ON authorities (username, authority);</script-text>
+    <method v="2" />
+  </configuration>
+</component>
\ No newline at end of file
diff --git a/presentation_notes.md b/presentation_notes.md
index 46cc4df..b50804c 100644
--- a/presentation_notes.md
+++ b/presentation_notes.md
@@ -40,7 +40,7 @@ Note: Die angeführte Struktur ist die Langfassung von Punkten, die ich in irgen
    - Character-Set (Buchstaben (klein/groß), Zahlen, (welche) Sonderzeichen?)
    - Wörter & Namen? → Wenn ja, Tauschregeln von Buchstaben (0 ↔ O, 1 ↔ l ↔ I ↔ !)
 
-### Salt & Pepper
+### Salt
 
 - "Gratis" Entropy, am Server angehängt
 - Salt: Unique pro Nutzer
@@ -50,6 +50,12 @@ Note: Die angeführte Struktur ist die Langfassung von Punkten, die ich in irgen
 
 - Tunable CPU & Memory usage um Brute-Force zu erschweren
 - Beispiele (Pbkdf, bcrypt, scrypt, ...)
+
+#### PBKDF2
+
+- key = pbkdf2(password, salt, iterations-count, hash-function, derived-key-len)
+- 
+
 - (Überleitung zu Demo)
 
 ### Demo
diff --git a/src/main/java/at/nanopenguin/fhtw/itse/pw_demo/CustomPbkdf2PasswordEncoder.java b/src/main/java/at/nanopenguin/fhtw/itse/pw_demo/CustomPbkdf2PasswordEncoder.java
new file mode 100644
index 0000000..669aefb
--- /dev/null
+++ b/src/main/java/at/nanopenguin/fhtw/itse/pw_demo/CustomPbkdf2PasswordEncoder.java
@@ -0,0 +1,115 @@
+package at.nanopenguin.fhtw.itse.pw_demo;
+
+import lombok.SneakyThrows;
+import org.springframework.boot.web.servlet.server.Encoding;
+import org.springframework.security.crypto.password.PasswordEncoder;
+import org.springframework.security.crypto.util.EncodingUtils;
+
+import javax.crypto.Mac;
+import javax.crypto.spec.SecretKeySpec;
+import java.nio.charset.StandardCharsets;
+import java.security.MessageDigest;
+import java.security.SecureRandom;
+import java.util.Base64;
+import java.util.function.Function;
+
+public class CustomPbkdf2PasswordEncoder implements PasswordEncoder {
+
+    private static final int SALT_LENGTH = 16; // 128 bits
+    private static final int ITERATIONS = 1024;
+
+    private final SecureRandom random = new SecureRandom();
+
+    @Override
+    public String encode(CharSequence rawPassword) {
+
+        byte[] salt = generateSalt();
+        byte[] hash = pbkdf2(
+                rawPassword.toString().getBytes(StandardCharsets.UTF_8),
+                salt,
+                ITERATIONS
+        );
+
+        return Base64.getEncoder().encodeToString(salt) + ":" + Base64.getEncoder().encodeToString(hash);
+    }
+
+    private byte[] generateSalt() {
+        byte[] salt = new byte[SALT_LENGTH];
+        random.nextBytes(salt);
+        return salt;
+    }
+
+    private byte[] pbkdf2(byte[] password, byte[] salt, int iterations) {
+
+        byte[] saltWithBlockNum = new byte[salt.length + 4];
+        System.arraycopy(salt, 0, saltWithBlockNum, 0, salt.length);
+        saltWithBlockNum[salt.length + 3] = 1;
+
+        byte[] u = hmac(password, saltWithBlockNum);
+        byte[] result = u.clone();
+
+        for (int i = 2; i <= iterations; i++) {
+            u = hmac(password, u);
+            xorInPlace(result, u);
+        }
+
+        return result;
+    }
+
+
+    private void xorInPlace(byte[] a, byte[] b) {
+        for (int i = 0; i < a.length; i++) {
+            a[i] ^= b[i];
+        }
+    }
+
+    private byte[] hmac(byte[] key, byte[] message) {
+        try {
+            MessageDigest sha256 = MessageDigest.getInstance("SHA-256");
+
+            // Key preparation
+            byte[] k = key;
+            if (key.length > 64) {
+                k = sha256.digest(key);
+                sha256.reset();
+            }
+            byte[] keyPadded = new byte[64];
+            System.arraycopy(k, 0, keyPadded, 0, k.length);
+
+            // Inner and outer padding
+            byte[] innerPad = new byte[64];
+            byte[] outerPad = new byte[64];
+            for (int i = 0; i < 64; i++) {
+                innerPad[i] = (byte) (keyPadded[i] ^ 0x36);
+                outerPad[i] = (byte) (keyPadded[i] ^ 0x5C);
+            }
+
+            // HMAC = SHA256(outerPad || SHA256(innerPad || message))
+            sha256.update(innerPad);
+            sha256.update(message);
+            byte[] innerHash = sha256.digest();
+
+            sha256.reset();
+            sha256.update(outerPad);
+            sha256.update(innerHash);
+            return sha256.digest();
+
+        } catch (Exception e) {
+            throw new RuntimeException(e);
+        }
+    }
+
+    @Override
+    public boolean matches(CharSequence rawPassword, String encodedPassword) {
+        String[] parts = encodedPassword.split(":");
+        byte[] salt = Base64.getDecoder().decode(parts[0]);
+        byte[] storedHash = Base64.getDecoder().decode(parts[1]);
+        byte[] testHash = pbkdf2(rawPassword.toString().getBytes(StandardCharsets.UTF_8), salt, ITERATIONS);
+
+        int diff = 0;
+        for (int i = 0; i < 32; i++) {
+            diff |= storedHash[i] ^ testHash[i];
+        }
+        return diff == 0;
+    }
+}
diff --git a/src/main/java/at/nanopenguin/fhtw/itse/pw_demo/RegistrationController.java b/src/main/java/at/nanopenguin/fhtw/itse/pw_demo/RegistrationController.java
new file mode 100644
index 0000000..e350bec
--- /dev/null
+++ b/src/main/java/at/nanopenguin/fhtw/itse/pw_demo/RegistrationController.java
@@ -0,0 +1,38 @@
+package at.nanopenguin.fhtw.itse.pw_demo;
+
+import lombok.RequiredArgsConstructor;
+import org.springframework.security.core.authority.SimpleGrantedAuthority;
+import org.springframework.security.core.userdetails.User;
+import org.springframework.security.crypto.password.PasswordEncoder;
+import org.springframework.security.provisioning.JdbcUserDetailsManager;
+import org.springframework.stereotype.Controller;
+import org.springframework.ui.Model;
+import org.springframework.web.bind.annotation.GetMapping;
+import org.springframework.web.bind.annotation.ModelAttribute;
+import org.springframework.web.bind.annotation.PostMapping;
+
+import java.util.Collections;
+
+@Controller
+@RequiredArgsConstructor
+public class RegistrationController {
+
+    private final JdbcUserDetailsManager userDetailsService;
+    private final SelectablePasswordEncoder encoder;
+
+    @GetMapping("/register")
+    public String showRegistrationForm(Model model) {
+        model.addAttribute("user", new UserDTO());
+        return "register";
+    }
+
+    @PostMapping("/register")
+    public String registerUser(@ModelAttribute UserDTO user, Model model) {
+        userDetailsService.createUser(
+            new User(user.getName(), encoder.encodeSelect(user.getPassword(), user.getEncoder()), Collections.singleton(new SimpleGrantedAuthority("USER")))
+        );
+        model.addAttribute("user", new UserDTO());
+        model.addAttribute("message", "User registered successfully!");
+        return "register";
+    }
+}
diff --git a/src/main/java/at/nanopenguin/fhtw/itse/pw_demo/SHA256PasswordEncoder.java b/src/main/java/at/nanopenguin/fhtw/itse/pw_demo/SHA256PasswordEncoder.java
new file mode 100644
index 0000000..cd120d7
--- /dev/null
+++ b/src/main/java/at/nanopenguin/fhtw/itse/pw_demo/SHA256PasswordEncoder.java
@@ -0,0 +1,28 @@
+package at.nanopenguin.fhtw.itse.pw_demo;
+
+import lombok.SneakyThrows;
+import org.springframework.security.crypto.password.PasswordEncoder;
+
+import java.nio.charset.StandardCharsets;
+import java.security.MessageDigest;
+import java.util.Base64;
+
+public class SHA256PasswordEncoder implements PasswordEncoder {
+
+    MessageDigest encoder;
+
+    @SneakyThrows // just a demo, so we can throw best practices out of the window :)
+    public SHA256PasswordEncoder() {
+        encoder = MessageDigest.getInstance("SHA-256");
+    }
+
+    @Override
+    public String encode(CharSequence rawPassword) {
+        return Base64.getEncoder().encodeToString(encoder.digest(rawPassword.toString().getBytes(StandardCharsets.UTF_8)));
+    }
+
+    @Override
+    public boolean matches(CharSequence rawPassword, String encodedPassword) {
+        return String.valueOf(this.encode(rawPassword)).equals(encodedPassword);
+    }
+}
diff --git a/src/main/java/at/nanopenguin/fhtw/itse/pw_demo/SecurityConfig.java b/src/main/java/at/nanopenguin/fhtw/itse/pw_demo/SecurityConfig.java
index 78365b9..dcb3980 100644
--- a/src/main/java/at/nanopenguin/fhtw/itse/pw_demo/SecurityConfig.java
+++ b/src/main/java/at/nanopenguin/fhtw/itse/pw_demo/SecurityConfig.java
@@ -18,6 +18,7 @@ import org.springframework.security.crypto.bcrypt.BCryptPasswordEncoder;
 import org.springframework.security.crypto.password.*;
 import org.springframework.security.crypto.scrypt.SCryptPasswordEncoder;
 import org.springframework.security.provisioning.InMemoryUserDetailsManager;
+import org.springframework.security.provisioning.JdbcUserDetailsManager;
 import org.springframework.security.web.SecurityFilterChain;
 
 import javax.sql.DataSource;
@@ -35,6 +36,7 @@ public class SecurityConfig {
         http
                 .formLogin(Customizer.withDefaults())
                 .authorizeHttpRequests(authorize -> authorize
+                        .requestMatchers("/register").permitAll()
                         .anyRequest().authenticated()
                 );
 
@@ -42,25 +44,24 @@ public class SecurityConfig {
     }
 
     @Bean
-    public UserDetailsService userDetailsService(PasswordEncoder passwordEncoder) {
-        UserDetailsService userDetailsService = new InMemoryUserDetailsManager( // TODO: JDBC
-                new User("Beni", passwordEncoder.encode("password"), Set.of(new SimpleGrantedAuthority("USER")))
-        );
-
-        return userDetailsService;
+    public JdbcUserDetailsManager jdbcUserDetailsManager(DataSource dataSource) {
+        return new JdbcUserDetailsManager(dataSource);
     }
 
     @Bean
-    public PasswordEncoder passwordEncoder() {
+    public SelectablePasswordEncoder passwordEncoder() {
         String defaultEncoder = "pbkdf2";
 
         Map<String, PasswordEncoder> encoders = new HashMap<>();
         encoders.put("noop", NoOpPasswordEncoder.getInstance());
-        encoders.put("pbkdf2", Pbkdf2PasswordEncoder.defaultsForSpringSecurity_v5_8());
-        encoders.put("scrypt", SCryptPasswordEncoder.defaultsForSpringSecurity_v5_8());
-        encoders.put("argon2", Argon2PasswordEncoder.defaultsForSpringSecurity_v5_8());
-        encoders.put("bcrypt", new BCryptPasswordEncoder());
-        encoders.put("sha256", new StandardPasswordEncoder());
-        return new DelegatingPasswordEncoder(defaultEncoder, encoders);
+        encoders.put("sha256", new SHA256PasswordEncoder());
+        encoders.put("md5", new MessageDigestPasswordEncoder("md5"));
+        encoders.put("pbkdf2", new CustomPbkdf2PasswordEncoder());
+        //encoders.put("pbkdf2", Pbkdf2PasswordEncoder.defaultsForSpringSecurity_v5_8());
+        //encoders.put("scrypt", SCryptPasswordEncoder.defaultsForSpringSecurity_v5_8());
+        //encoders.put("argon2", Argon2PasswordEncoder.defaultsForSpringSecurity_v5_8());
+        //encoders.put("bcrypt", new BCryptPasswordEncoder());
+        //encoders.put("sha256", new StandardPasswordEncoder());
+        return new SelectablePasswordEncoder(defaultEncoder, encoders);
     }
 }
diff --git a/src/main/java/at/nanopenguin/fhtw/itse/pw_demo/SelectablePasswordEncoder.java b/src/main/java/at/nanopenguin/fhtw/itse/pw_demo/SelectablePasswordEncoder.java
new file mode 100644
index 0000000..577d9e2
--- /dev/null
+++ b/src/main/java/at/nanopenguin/fhtw/itse/pw_demo/SelectablePasswordEncoder.java
@@ -0,0 +1,144 @@
+package at.nanopenguin.fhtw.itse.pw_demo;
+
+import org.springframework.security.crypto.password.PasswordEncoder;
+
+import java.util.HashMap;
+import java.util.Map;
+
+public class SelectablePasswordEncoder implements PasswordEncoder {
+    private static final String DEFAULT_ID_PREFIX = "{";
+    private static final String DEFAULT_ID_SUFFIX = "}";
+    private static final String NO_PASSWORD_ENCODER_MAPPED = "There is no password encoder mapped for the id '%s'. Check your configuration to ensure it matches one of the registered encoders.";
+    private static final String NO_PASSWORD_ENCODER_PREFIX = "Given that there is no default password encoder configured, each password must have a password encoding prefix. Please either prefix this password with '{noop}' or set a default password encoder in `SelectablePasswordEncoder`.";
+    private static final String MALFORMED_PASSWORD_ENCODER_PREFIX = "The name of the password encoder is improperly formatted or incomplete. The format should be '%sENCODER%spassword'.";
+    private final String idPrefix;
+    private final String idSuffix;
+    private final String idForEncode;
+    private final PasswordEncoder passwordEncoderForEncode;
+    private final Map<String, PasswordEncoder> idToPasswordEncoder;
+    private PasswordEncoder defaultPasswordEncoderForMatches;
+
+    public SelectablePasswordEncoder(String idForEncode, Map<String, PasswordEncoder> idToPasswordEncoder) {
+        this(idForEncode, idToPasswordEncoder, "{", "}");
+    }
+
+    public SelectablePasswordEncoder(String idForEncode, Map<String, PasswordEncoder> idToPasswordEncoder, String idPrefix, String idSuffix) {
+        this.defaultPasswordEncoderForMatches = new UnmappedIdPasswordEncoder();
+        if (idForEncode == null) {
+            throw new IllegalArgumentException("idForEncode cannot be null");
+        } else if (idPrefix == null) {
+            throw new IllegalArgumentException("prefix cannot be null");
+        } else if (idSuffix != null && !idSuffix.isEmpty()) {
+            if (idPrefix.contains(idSuffix)) {
+                throw new IllegalArgumentException("idPrefix " + idPrefix + " cannot contain idSuffix " + idSuffix);
+            } else if (!idToPasswordEncoder.containsKey(idForEncode)) {
+                throw new IllegalArgumentException("idForEncode " + idForEncode + "is not found in idToPasswordEncoder " + String.valueOf(idToPasswordEncoder));
+            } else {
+                for(String id : idToPasswordEncoder.keySet()) {
+                    if (id != null) {
+                        if (!idPrefix.isEmpty() && id.contains(idPrefix)) {
+                            throw new IllegalArgumentException("id " + id + " cannot contain " + idPrefix);
+                        }
+
+                        if (id.contains(idSuffix)) {
+                            throw new IllegalArgumentException("id " + id + " cannot contain " + idSuffix);
+                        }
+                    }
+                }
+
+                this.idForEncode = idForEncode;
+                this.passwordEncoderForEncode = (PasswordEncoder)idToPasswordEncoder.get(idForEncode);
+                this.idToPasswordEncoder = new HashMap(idToPasswordEncoder);
+                this.idPrefix = idPrefix;
+                this.idSuffix = idSuffix;
+            }
+        } else {
+            throw new IllegalArgumentException("suffix cannot be empty");
+        }
+    }
+
+    public void setDefaultPasswordEncoderForMatches(PasswordEncoder defaultPasswordEncoderForMatches) {
+        if (defaultPasswordEncoderForMatches == null) {
+            throw new IllegalArgumentException("defaultPasswordEncoderForMatches cannot be null");
+        } else {
+            this.defaultPasswordEncoderForMatches = defaultPasswordEncoderForMatches;
+        }
+    }
+
+    public String encode(CharSequence rawPassword) {
+        String var10000 = this.idPrefix;
+        return var10000 + this.idForEncode + this.idSuffix + this.passwordEncoderForEncode.encode(rawPassword);
+    }
+
+    public String encodeSelect(CharSequence rawPassword, String encoder) {
+        String var10000 = this.idPrefix;;
+        return var10000 + encoder + this.idSuffix + this.idToPasswordEncoder.get(encoder).encode(rawPassword);
+    }
+
+    public boolean matches(CharSequence rawPassword, String prefixEncodedPassword) {
+        if (rawPassword == null && prefixEncodedPassword == null) {
+            return true;
+        } else {
+            String id = this.extractId(prefixEncodedPassword);
+            PasswordEncoder delegate = (PasswordEncoder)this.idToPasswordEncoder.get(id);
+            if (delegate == null) {
+                return this.defaultPasswordEncoderForMatches.matches(rawPassword, prefixEncodedPassword);
+            } else {
+                String encodedPassword = this.extractEncodedPassword(prefixEncodedPassword);
+                return delegate.matches(rawPassword, encodedPassword);
+            }
+        }
+    }
+
+    private String extractId(String prefixEncodedPassword) {
+        if (prefixEncodedPassword == null) {
+            return null;
+        } else {
+            int start = prefixEncodedPassword.indexOf(this.idPrefix);
+            if (start != 0) {
+                return null;
+            } else {
+                int end = prefixEncodedPassword.indexOf(this.idSuffix, start);
+                return end < 0 ? null : prefixEncodedPassword.substring(start + this.idPrefix.length(), end);
+            }
+        }
+    }
+
+    public boolean upgradeEncoding(String prefixEncodedPassword) {
+        String id = this.extractId(prefixEncodedPassword);
+        if (!this.idForEncode.equalsIgnoreCase(id)) {
+            return true;
+        } else {
+            String encodedPassword = this.extractEncodedPassword(prefixEncodedPassword);
+            return ((PasswordEncoder)this.idToPasswordEncoder.get(id)).upgradeEncoding(encodedPassword);
+        }
+    }
+
+    private String extractEncodedPassword(String prefixEncodedPassword) {
+        int start = prefixEncodedPassword.indexOf(this.idSuffix);
+        return prefixEncodedPassword.substring(start + this.idSuffix.length());
+    }
+
+    private class UnmappedIdPasswordEncoder implements PasswordEncoder {
+        public String encode(CharSequence rawPassword) {
+            throw new UnsupportedOperationException("encode is not supported");
+        }
+
+        public boolean matches(CharSequence rawPassword, String prefixEncodedPassword) {
+            String id = SelectablePasswordEncoder.this.extractId(prefixEncodedPassword);
+            if (id != null && !id.isBlank()) {
+                throw new IllegalArgumentException(String.format("There is no password encoder mapped for the id '%s'. Check your configuration to ensure it matches one of the registered encoders.", id));
+            } else {
+                if (prefixEncodedPassword != null && !prefixEncodedPassword.isBlank()) {
+                    int start = prefixEncodedPassword.indexOf(SelectablePasswordEncoder.this.idPrefix);
+                    int end = prefixEncodedPassword.indexOf(SelectablePasswordEncoder.this.idSuffix, start);
+                    if (start < 0 && end < 0) {
+                        throw new IllegalArgumentException("Given that there is no default password encoder configured, each password must have a password encoding prefix. Please either prefix this password with '{noop}' or set a default password encoder in `SelectablePasswordEncoder`.");
+                    }
+                }
+
+                throw new IllegalArgumentException(String.format("The name of the password encoder is improperly formatted or incomplete. The format should be '%sENCODER%spassword'.", SelectablePasswordEncoder.this.idPrefix, SelectablePasswordEncoder.this.idSuffix));
+            }
+        }
+    }
+}
diff --git a/src/main/java/at/nanopenguin/fhtw/itse/pw_demo/UserDTO.java b/src/main/java/at/nanopenguin/fhtw/itse/pw_demo/UserDTO.java
new file mode 100644
index 0000000..725e89d
--- /dev/null
+++ b/src/main/java/at/nanopenguin/fhtw/itse/pw_demo/UserDTO.java
@@ -0,0 +1,12 @@
+package at.nanopenguin.fhtw.itse.pw_demo;
+
+import lombok.Getter;
+import lombok.Setter;
+
+@Getter
+@Setter
+public class UserDTO {
+    private String name;
+    private String password;
+    private String encoder;
+}
diff --git a/src/main/java/at/nanopenguin/fhtw/itse/pw_demo/WelcomeController.java b/src/main/java/at/nanopenguin/fhtw/itse/pw_demo/WelcomeController.java
index 2bca5bc..14ddf8b 100644
--- a/src/main/java/at/nanopenguin/fhtw/itse/pw_demo/WelcomeController.java
+++ b/src/main/java/at/nanopenguin/fhtw/itse/pw_demo/WelcomeController.java
@@ -17,5 +17,4 @@ public class WelcomeController {
 
         return "welcome";
     }
-
 }
diff --git a/src/main/resources/templates/register.html b/src/main/resources/templates/register.html
new file mode 100644
index 0000000..dd3a5dd
--- /dev/null
+++ b/src/main/resources/templates/register.html
@@ -0,0 +1,43 @@
+<!DOCTYPE html>
+<html xmlns:th="http://www.thymeleaf.org" lang="en">
+<head>
+    <title>Welcome!</title>
+    <link href="/default-ui.css" rel="stylesheet">
+</head>
+<body>
+<div class="content">
+    <h2>Register User</h2>
+
+    <form th:action="@{/register}" th:object="${user}" method="post">
+        <div>
+            <label for="name">Name:</label>
+            <input type="text" id="name" th:field="*{name}" required>
+        </div>
+
+        <div>
+            <label for="password">Password:</label>
+            <input type="password" id="password" th:field="*{password}" required>
+        </div>
+
+        <div>
+            <label for="encoder">Password Encoder:</label>
+            <select id="encoder" th:field="*{encoder}" required>
+                <option value="">-- Select Encoder --</option>
+                <option value="pbkdf2">PBKDF2</option>
+                <option value="sha256">Unsalted SHA256</option>
+                <option value="md5">MD5</option>
+                <option value="noop">NoOp (Plain Text)</option>
+            </select>
+        </div>
+
+        <div>
+            <button type="submit">Register</button>
+        </div>
+    </form>
+
+    <div th:if="${message}">
+        <p th:text="${message}"></p>
+    </div>
+</div>
+</body>
+</html>
\ No newline at end of file