✨ feat: Pbkdf2PasswordEncoder 작성 (#53)

src/main/java/com/smunity/petition/global/config/encoder/Pbkdf2PasswordEncoder.java

@@ -0,0 +1,64 @@
+package com.smunity.petition.global.config.encoder;
+
+import com.google.common.base.Charsets;
+import lombok.val;
+import org.springframework.security.crypto.keygen.KeyGenerators;
+import org.springframework.security.crypto.keygen.StringKeyGenerator;
+import org.springframework.security.crypto.password.PasswordEncoder;
+
+import javax.crypto.SecretKeyFactory;
+import javax.crypto.spec.PBEKeySpec;
+import java.security.GeneralSecurityException;
+import java.security.MessageDigest;
+import java.util.Arrays;
+import java.util.Base64;
+
+public class Pbkdf2PasswordEncoder implements PasswordEncoder {
+    private final StringKeyGenerator saltGenerator = KeyGenerators.string();
+    private final String PREFIX = "pbkdf2_sha256";
+    private final int ITERATIONS = 390000;
+    private final int HASH_WIDTH = 256;
+    private final String ALGORITHM = "PBKDF2WithHmacSHA256";
+
+    private byte[] base64Decode(String string) {
+        return Base64.getDecoder().decode(string);
+    }
+
+    private String base64Encode(byte[] bytes) {
+        return Base64.getEncoder().encodeToString(bytes);
+    }
+
+    private byte[] encodeWithSaltAndIterations(CharSequence rawPassword, byte[] salt, int iterations) {
+        val keySpec = new PBEKeySpec(rawPassword.toString().toCharArray(), salt, iterations, HASH_WIDTH);
+        try {
+            return SecretKeyFactory.getInstance(ALGORITHM).generateSecret(keySpec).getEncoded();
+        } catch (GeneralSecurityException e) {
+            throw new IllegalStateException("Could not create hash", e);
+        }
+    }
+
+    private byte[] encodeWithSalt(CharSequence rawPassword, byte[] salt) {
+        return encodeWithSaltAndIterations(rawPassword, salt, ITERATIONS);
+    }
+
+    @Override
+    public String encode(CharSequence rawPassword) {
+        val salt = saltGenerator.generateKey();
+        val hash = encodeWithSalt(rawPassword, salt.getBytes(Charsets.US_ASCII));
+        val encodedHash = base64Encode(hash);
+        return String.join("$", Arrays.asList(PREFIX, Integer.toString(ITERATIONS), salt, encodedHash));
+    }
+
+    @Override
+    public boolean matches(CharSequence rawPassword, String encodedPassword) {
+        if (!encodedPassword.startsWith(PREFIX))
+            throw new IllegalArgumentException("Encoded password does not start with: $PREFIX");
+        val parts = encodedPassword.split("\\$");
+        if (parts.length != 4)
+            throw new IllegalArgumentException("The encoded password format does not have 4 parts");
+        val iterations = Integer.parseInt(parts[1]);
+        val salt = parts[2].getBytes(Charsets.US_ASCII);
+        val hash = base64Decode(parts[3]);
+        return MessageDigest.isEqual(hash, encodeWithSaltAndIterations(rawPassword, salt, iterations));
+    }
+}