#1095 Update SMF hash algorithm to generate salt as SMF does

- The salt isn't used for password hashing but SMF requires that there be one to generate the authentication cookie. This does not yet enable registration from Minecraft: SMF has other non-null columns that need to be tackled. This is a first step.

src/main/java/fr/xephi/authme/security/crypts/Smf.java

@@ -1,12 +1,47 @@
 package fr.xephi.authme.security.crypts;
 
 import fr.xephi.authme.security.HashUtils;
+import fr.xephi.authme.security.crypts.description.HasSalt;
+import fr.xephi.authme.security.crypts.description.Recommendation;
+import fr.xephi.authme.security.crypts.description.SaltType;
+import fr.xephi.authme.security.crypts.description.Usage;
+import fr.xephi.authme.util.RandomStringUtils;
 
-public class Smf extends UsernameSaltMethod {
+/**
+ * Hashing algorithm for SMF forums.
+ * <p>
+ * The hash algorithm is {@code sha1(strtolower($username) . $password)}. However, an additional four-character
+ * salt is generated for each user, used to generate the login cookie. Therefore, this implementation generates a salt
+ * and declares that it requires a separate salt (the SMF members table has a not-null constraint on the salt column).
+ *
+ * @see <a href="https://www.simplemachines.org/">Simple Machines Forum</a>
+ */
+@Recommendation(Usage.DO_NOT_USE)
+@HasSalt(SaltType.USERNAME)
+public class Smf implements EncryptionMethod {
 
     @Override
     public HashedPassword computeHash(String password, String name) {
-        return new HashedPassword(HashUtils.sha1(name.toLowerCase() + password));
+        return new HashedPassword(computeHash(password, null, name), generateSalt());
     }
 
+    @Override
+    public String computeHash(String password, String salt, String name) {
+        return HashUtils.sha1(name.toLowerCase() + password);
+    }
+
+    @Override
+    public boolean comparePassword(String password, HashedPassword hashedPassword, String name) {
+        return computeHash(password, null, name).equals(hashedPassword.getHash());
+    }
+
+    @Override
+    public String generateSalt() {
+        return RandomStringUtils.generate(4);
+    }
+
+    @Override
+    public boolean hasSeparateSalt() {
+        return true;
+    }
 }