1.4.0

2 files changed, 140 insertions, 10 deletions

diff --git a/src/main/java/org/uic/barcode/utils/SecurityUtils.java b/src/main/java/org/uic/barcode/utils/SecurityUtils.java
index 5fdbda7..8c981af 100644
--- a/src/main/java/org/uic/barcode/utils/SecurityUtils.java
+++ b/src/main/java/org/uic/barcode/utils/SecurityUtils.java
@@ -1,5 +1,8 @@
 package org.uic.barcode.utils;

 

+import java.io.ByteArrayOutputStream;

+import java.io.IOException;

+import java.math.BigInteger;

 import java.security.KeyFactory;

 import java.security.NoSuchAlgorithmException;

 import java.security.PrivateKey;

@@ -10,6 +13,7 @@ import java.security.Security;
 import java.security.spec.InvalidKeySpecException;

 import java.security.spec.PKCS8EncodedKeySpec;

 import java.security.spec.X509EncodedKeySpec;

+import java.util.Arrays;

 

 /**

  * The Class SecurityUtils.

@@ -182,4 +186,129 @@ public class SecurityUtils {
 		

 		return null;

 	}

+	

+	/**

+	 * Decode signature integer sequence.

+	 * 

+	 * Support function to decode a DSA signature

+	 * Provides the two DSA signature parameter encoded in a DSA signature

+	 *

+	 * @param bytes the bytes

+	 * @return the big integer[]

+	 * @throws Exception the exception

+	 */

+	public static BigInteger[] decodeSignatureIntegerSequence(byte[] bytes) throws Exception {

+

+		int sequenceTag = (int) bytes[0];

+		

+		if (sequenceTag != 48) throw new Exception("signature is not a sequence");

+		

+		int sequenceLength = (int) bytes[1];

+		

+		if (sequenceLength < 6) throw new Exception("signature sequence too short");

+		

+		BigInteger[] result = new BigInteger[2];

+		

+		int offset = 2;

+		int i = 0;

+		while (offset < bytes.length && i < 2) {

+			int integerTag = (int) bytes[offset];

+			if (integerTag != 2) throw new Exception("signature is not an integer sequence");

+			int integerLength = (int) bytes[offset + 1];

+			byte[] value = Arrays.copyOfRange(bytes, offset + 2, offset + 2 + integerLength);		

+			result[i] = new BigInteger(+1, value);

+			offset = offset + integerLength + 2;

+			i++;

+		}

+

+		return result;

+	}

+	

+	/**

+	 * Encode signature integer sequence.

+	 *  

+	 *  Support function to format two parameters as DER encoded integer list 

+	 *  to get a valid formated DSA signature from the signature parameter

+	 *

+	 * @param i1 the i 1

+	 * @param i2 the i 2

+	 * @return the byte[]

+	 * @throws IOException Signals that an I/O exception has occurred.

+	 */

+	public static byte[] encodeSignatureIntegerSequence(BigInteger i1, BigInteger i2) throws IOException {

+		

+		//SEQUENCE OF --> tag 16

+		int sequenceTag = 16 + 32;  // (bits 6 = 1 constructed)

+		//INTEGER     --> tag 2

+		int integerTag = 2;

+			

+		byte[] b1 = i1.toByteArray();

+        int lb1 = b1.length;

+		byte[] b2 = i2.toByteArray();

+        int lb2 = b2.length;		

+        

+        int sequenceLength = lb1 + lb2 + 4;

+		

+		ByteArrayOutputStream out = new ByteArrayOutputStream();

+		

+		out.write((byte) sequenceTag);

+		out.write((byte) sequenceLength);   

+		out.write((byte) integerTag);  

+		out.write((byte) lb1);  

+		out.write(b1);   

+		out.write((byte) integerTag);  

+		out.write((byte) lb2);  

+		out.write(b2);   

+

+		return out.toByteArray();

+	}

+

+	public static byte[] recombineDsaSignature(byte[] sealdata) throws IOException {

+		

+		//check whether the encoding is wrong and the sealdata contain a signature

+		//remove trailing zeroes from the signature

+		BigInteger[] bInts = null;

+		try {

+			bInts = decodeSignatureIntegerSequence(sealdata);

+			byte[] sig = encodeSignatureIntegerSequence(bInts[0],bInts[1]);

+			//decoding the entire signature was ok, so there was no split

+			return sig;

+		} catch (Exception e) {

+			//the signature is correctly implemented, continue with recombination

+		}

+

+		// split the data into two blocks

+		int length = sealdata.length / 2;

+		byte[] rBytes = Arrays.copyOfRange(sealdata,      0, length);

+		byte[] sBytes = Arrays.copyOfRange(sealdata, length, length + length);	

+		

+		//convert to BigInteger to get rid of leading zeroes

+		BigInteger r = new BigInteger(1,rBytes);

+		BigInteger s = new BigInteger(1,sBytes);	

+		

+		//encode as DSA signature structure

+		//SEQUENCE OF --> tag 16

+		int sequenceTag = 16 + 32;  // (bits 6 = 1 constructed)

+		//INTEGER     --> tag 2

+		int integerTag = 2;

+		

+		byte[] b1 = r.toByteArray();

+        int lb1 = b1.length;     

+

+        byte[] b2 = s.toByteArray();	

+        int lb2 = b2.length;		

+        int sequenceLength = lb1 + lb2 + 4;

+		

+		ByteArrayOutputStream out = new ByteArrayOutputStream();

+		out.write((byte) sequenceTag);

+		out.write((byte) sequenceLength);   

+		out.write((byte) integerTag);  

+		out.write((byte) lb1);  

+		out.write(b1);   

+		out.write((byte) integerTag);  

+		out.write((byte) lb2);  

+		out.write(b2);   

+		return out.toByteArray();		

+

+	}

 }

diff --git a/src/main/java/org/uic/barcode/utils/package.html b/src/main/java/org/uic/barcode/utils/package.html
index 45a73a9..73917d7 100644
--- a/src/main/java/org/uic/barcode/utils/package.html
+++ b/src/main/java/org/uic/barcode/utils/package.html
@@ -3,18 +3,19 @@
 <head></head>

 <body>

 

-<h1>Implementation of the header frames to bundle all data for a bar code.</h1>

+	<h1>Implementation of the header frames to bundle all data for a

+		bar code.</h1>

 

-<p>

+	<p>

 

-  Provides a decoding and encoding of the header data frames for:<br/><br/>

-  

-  <ul>

-  <li> static header as defined in UIC IRS 90918-9</li>

-  <li> dynamic header as drafted for the UIC IRS 90918-9</li>

+		Provides a decoding and encoding of the header data frames for:<br />

+		<br />

+	<ul>

+		<li>static header as defined in UIC IRS 90918-9</li>

+		<li>dynamic header as drafted for the UIC IRS 90918-9</li>

+

+	</ul>

+	</p>

 

-  </ul>

-</p>

-  

 </body>

 </html>
\ No newline at end of file