Added JWSUtils class;

openid-connect-server/src/main/java/org/mitre/openid/connect/util/JWSUtils.java

@@ -0,0 +1,68 @@
+package org.mitre.openid.connect.util;
+
+import java.security.InvalidKeyException;
+import java.security.NoSuchAlgorithmException;
+import java.util.Arrays;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+
+import javax.crypto.Mac;
+import javax.crypto.spec.SecretKeySpec;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import com.nimbusds.jose.JWSAlgorithm;
+import com.nimbusds.jose.util.Base64URL;
+
+/**
+ * Utility class for JWS processing. 
+ * 
+ * @author Amanda Anganes
+ *
+ */
+public class JWSUtils {
+
+	private static Logger logger = LoggerFactory.getLogger(JWSUtils.class);
+	
+	public static Base64URL getAccessTokenHash(JWSAlgorithm signingAlg, byte[] tokenBytes) {
+		
+		//Switch based on the given signing algorithm
+		
+		String algName = signingAlg.getName();
+		
+		if (algName.equals(JWSAlgorithm.HS256)) {
+			
+		}
+		
+		Pattern re = Pattern.compile("^[HRE]S(\\d+)$");
+		Matcher match = re.matcher(algName);
+		if (match.matches()) {
+			String bits = match.group(1);
+			String hmacAlg = "HMACSHA" + bits;
+			try {
+				Mac mac = Mac.getInstance(hmacAlg);
+				mac.init(new SecretKeySpec(tokenBytes, hmacAlg));
+
+				byte[] at_hash_bytes = mac.doFinal();
+				byte[] at_hash_bytes_left = Arrays.copyOf(at_hash_bytes, at_hash_bytes.length / 2);
+				Base64URL at_hash = Base64URL.encode(at_hash_bytes_left);
+
+				return at_hash;
+
+			} catch (NoSuchAlgorithmException e) {
+				
+				logger.error("No such algorithm error: ", e);
+				
+			} catch (InvalidKeyException e) {
+				
+				logger.error("Invalid key error: ", e);
+			}
+
+		}
+		
+		return null;
+
+	}
+	
+}