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authorCGantert345 <57003061+CGantert345@users.noreply.github.com>2023-03-13 13:27:13 +0100
committerCGantert345 <57003061+CGantert345@users.noreply.github.com>2023-03-13 13:27:13 +0100
commit94d0ba8bdd36c6621e2478fdb3bcf1c790369006 (patch)
treeee957619b41f45d3c1d68d2a75b660f2ab6e10c9 /src/main/java/org/uic/barcode
parentssb unit tests (diff)
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Diffstat (limited to 'src/main/java/org/uic/barcode')
-rw-r--r--src/main/java/org/uic/barcode/ssbFrame/SsbFrame.java29
-rw-r--r--src/main/java/org/uic/barcode/utils/SecurityUtils.java48
2 files changed, 71 insertions, 6 deletions
diff --git a/src/main/java/org/uic/barcode/ssbFrame/SsbFrame.java b/src/main/java/org/uic/barcode/ssbFrame/SsbFrame.java
index 1ee68bb..b473c1e 100644
--- a/src/main/java/org/uic/barcode/ssbFrame/SsbFrame.java
+++ b/src/main/java/org/uic/barcode/ssbFrame/SsbFrame.java
@@ -1,5 +1,6 @@
package org.uic.barcode.ssbFrame;
+import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.math.BigInteger;
import java.security.InvalidKeyException;
@@ -76,17 +77,33 @@ public class SsbFrame {
offset = offset + nonUicData.decodeContent(bytes,offset);
}
-
- signaturePart1 = new byte[28];
- signaturePart2 = new byte[28];
- for (int i = 0 ; i < 28;i++) {
- signaturePart1[i] = bytes[58 + i];
- signaturePart2[i] = bytes[58 + 28 + i];
+ byte[] signatureBytes = new byte[56];
+
+ try {
+ //check for non-standard signature encoding
+ BigInteger[] bInts = SecurityUtils.decodeSignatureIntegerSequence(signatureBytes);
+ byte[] sig = SecurityUtils.encodeSignatureIntegerSequence(bInts[0],bInts[1]);
+ signaturePart1 = bInts[0].toByteArray();
+ signaturePart2 = bInts[1].toByteArray();
+ //decoding the entire signature was ok, so there was no split
+ } catch (Exception e) {
+ //the signature is correctly implemented, continue with recombination
+ signaturePart1 = new byte[28];
+ signaturePart2 = new byte[28];
+
+ for (int i = 0 ; i < 28;i++) {
+ signaturePart1[i] = bytes[58 + i];
+ signaturePart2[i] = bytes[58 + 28 + i];
+ }
}
+
}
+
+
+
public byte[] encode() throws EncodingFormatException {
byte[] bytes = new byte[114];
diff --git a/src/main/java/org/uic/barcode/utils/SecurityUtils.java b/src/main/java/org/uic/barcode/utils/SecurityUtils.java
index 29a2346..8c981af 100644
--- a/src/main/java/org/uic/barcode/utils/SecurityUtils.java
+++ b/src/main/java/org/uic/barcode/utils/SecurityUtils.java
@@ -263,4 +263,52 @@ public class SecurityUtils {
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();
+
+ }
}