MessageAuthenticator

https://coova.github.io/JRadius/
https://coova.github.io/JRadius/

import org.tinyradius.packet.RadiusPacket;
import org.tinyradius.util.RadiusUtil;
import java.nio.charset.StandardCharsets;public class RadiusAuthUtils {/*** 生成 RADIUS 報文的 Message-Authenticator 值* @param sharedSecret 共享密鑰* @param requestAuthenticator 請求認證器（16 字節隨機數）* @param packetBytes 完整的 RADIUS 報文字節數據（包含報文頭和屬性）* @return Message-Authenticator 的字節數組（16 字節）*/public static byte[] generateMessageAuthenticator(String sharedSecret, byte[] requestAuthenticator, byte[] packetBytes) {try {// 1. 使用 HMAC-MD5 計算哈希byte[] hmacMd5 = RadiusUtil.getMd5Digest(sharedSecret.getBytes(StandardCharsets.UTF_8), packetBytes);// 2. 提取前 16 字節作為 Message-Authenticatorbyte[] messageAuthenticator = new byte[16];System.arraycopy(hmacMd5, 0, messageAuthenticator, 0, 16);return messageAuthenticator;} catch (Exception e) {throw new RuntimeException("生成 Message-Authenticator 失敗", e);}}
}

public static byte[] generateMessageAuthenticator(byte[] sharedSecret, RADIUS packet) {try {byte[] messageBytes = packet.getBytes(); SecretKeySpec secretKeySpec = new SecretKeySpec(sharedSecret, "HmacMD5");Mac mac = Mac.getInstance("HmacMD5"); mac.init(secretKeySpec); byte[] macValue = mac.doFinal(messageBytes); Attribute macAttribute = new MessageAuthenticator(macValue);List<Attribute> attributes = packet.getAttributes(); attributes.add(macAttribute); return macValue;} catch (NoSuchAlgorithmException | InvalidKeyException e) {throw new RuntimeException("Failed to generate Message-Authenticator", e);}
}

jradius-1.1.5

package net.jradius.util;import java.security.InvalidKeyException;
import java.security.NoSuchAlgorithmException;
import java.util.Arrays;
import java.io.IOException;
import java.nio.ByteBuffer;import net.jradius.packet.RadiusFormat;
import net.jradius.packet.RadiusPacket;
import net.jradius.packet.attribute.AttributeDictionary;
import net.jradius.packet.attribute.AttributeFactory;
import net.jradius.packet.attribute.RadiusAttribute;public class MessageAuthenticator 
{private static final RadiusFormat format = RadiusFormat.getInstance();public static void generateRequestMessageAuthenticator(RadiusPacket request, String sharedSecret) throws IOException, InvalidKeyException, NoSuchAlgorithmException{byte[] hash = new byte[16];ByteBuffer buffer = ByteBuffer.allocate(4096);request.overwriteAttribute(AttributeFactory.newAttribute(AttributeDictionary.MESSAGE_AUTHENTICATOR, hash, request.isRecyclable()));format.packPacket(request, sharedSecret, buffer, true);System.arraycopy(MD5.hmac_md5(buffer.array(), 0, buffer.position(), sharedSecret.getBytes()), 0, hash, 0, 16);}public static void generateResponseMessageAuthenticator(RadiusPacket request, RadiusPacket reply, String sharedSecret) throws IOException, InvalidKeyException, NoSuchAlgorithmException{byte[] hash = new byte[16];byte[] requestAuth = request.getAuthenticator();byte[] replyAuth = reply.getAuthenticator();ByteBuffer buffer = ByteBuffer.allocate(4096);reply.setAuthenticator(requestAuth);reply.overwriteAttribute(AttributeFactory.newAttribute(AttributeDictionary.MESSAGE_AUTHENTICATOR, hash, reply.isRecyclable()));format.packPacket(reply, sharedSecret, buffer, true);System.arraycopy(MD5.hmac_md5(buffer.array(), 0, buffer.position(), sharedSecret.getBytes()), 0, hash, 0, 16);reply.setAuthenticator(replyAuth);}public static Boolean verifyRequest(RadiusPacket request, String sharedSecret) throws IOException, InvalidKeyException, NoSuchAlgorithmException{byte[] hash = new byte[16];ByteBuffer buffer = ByteBuffer.allocate(4096);RadiusAttribute attr = request.findAttribute(AttributeDictionary.MESSAGE_AUTHENTICATOR);if (attr == null) return null;byte[] pval = attr.getValue().getBytes();attr.setValue(hash);format.packPacket(request, sharedSecret, buffer, true);System.arraycopy(MD5.hmac_md5(buffer.array(), 0, buffer.position(), sharedSecret.getBytes()), 0, hash, 0, 16);attr.setValue(pval);return new Boolean(Arrays.equals(pval, hash));}public static Boolean verifyReply(byte[] requestAuth, RadiusPacket reply, String sharedSecret) throws IOException, InvalidKeyException, NoSuchAlgorithmException{byte[] replyAuth = reply.getAuthenticator();byte[] hash = new byte[16];ByteBuffer buffer = ByteBuffer.allocate(4096);RadiusAttribute attr = reply.findAttribute(AttributeDictionary.MESSAGE_AUTHENTICATOR);if (attr == null) return null;byte[] pval = attr.getValue().getBytes();attr.setValue(hash);reply.setAuthenticator(requestAuth);format.packPacket(reply, sharedSecret, buffer, true);System.arraycopy(MD5.hmac_md5(buffer.array(), 0, buffer.position(), sharedSecret.getBytes()), 0, hash, 0, 16);reply.setAuthenticator(replyAuth);return new Boolean(Arrays.equals(pval, hash));}
}