diff options
Diffstat (limited to 'src/main')
| -rw-r--r-- | src/main/java/org/uic/barcode/ssbFrame/SsbFrame.java | 29 | ||||
| -rw-r--r-- | src/main/java/org/uic/barcode/utils/SecurityUtils.java | 48 |
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();
+
+ }
}
|