private boolean isDSSDictionaryPresentInPreviousRevision(byte[] originalBytes) { ByteArrayInputStream bais = null; PDDocument doc = null; PdfDssDict dssDictionary = null; try { bais = new ByteArrayInputStream(originalBytes); doc = PDDocument.load(bais); List<PDSignature> pdSignatures = doc.getSignatureDictionaries(); if (CollectionUtils.isNotEmpty(pdSignatures)) { PdfDict catalog = new PdfBoxDict(doc.getDocumentCatalog().getCOSDictionary(), doc); dssDictionary = PdfDssDict.extract(catalog); } } catch (Exception e) { logger.warn( "Cannot check in previous revisions if DSS dictionary already exist : " + e.getMessage(), e); } finally { IOUtils.closeQuietly(bais); IOUtils.closeQuietly(doc); } return dssDictionary != null; }
@Override protected void onDocumentSigned(byte[] byteArray) { try { InputStream inputStream = new ByteArrayInputStream(byteArray); PDDocument document = PDDocument.load(inputStream); List<PDSignature> signatures = document.getSignatureDictionaries(); assertEquals(1, signatures.size()); for (PDSignature pdSignature : signatures) { byte[] contents = pdSignature.getContents(byteArray); byte[] signedContent = pdSignature.getSignedContent(byteArray); logger.info("Byte range : " + Arrays.toString(pdSignature.getByteRange())); // IOUtils.write(contents, new FileOutputStream("sig.p7s")); ASN1InputStream asn1sInput = new ASN1InputStream(contents); ASN1Sequence asn1Seq = (ASN1Sequence) asn1sInput.readObject(); logger.info("SEQ : " + asn1Seq.toString()); ASN1ObjectIdentifier oid = ASN1ObjectIdentifier.getInstance(asn1Seq.getObjectAt(0)); assertEquals(PKCSObjectIdentifiers.signedData, oid); SignedData signedData = SignedData.getInstance(DERTaggedObject.getInstance(asn1Seq.getObjectAt(1)).getObject()); ASN1Set digestAlgorithmSet = signedData.getDigestAlgorithms(); ASN1ObjectIdentifier oidDigestAlgo = ASN1ObjectIdentifier.getInstance( ASN1Sequence.getInstance(digestAlgorithmSet.getObjectAt(0)).getObjectAt(0)); DigestAlgorithm digestAlgorithm = DigestAlgorithm.forOID(oidDigestAlgo.getId()); logger.info("DIGEST ALGO : " + digestAlgorithm); ContentInfo encapContentInfo = signedData.getEncapContentInfo(); ASN1ObjectIdentifier contentTypeOID = encapContentInfo.getContentType(); logger.info("ENCAPSULATED CONTENT INFO TYPE : " + contentTypeOID); assertEquals(PKCSObjectIdentifiers.data, contentTypeOID); ASN1Encodable content = encapContentInfo.getContent(); logger.info("ENCAPSULATED CONTENT INFO CONTENT : " + content); assertNull(content); List<X509Certificate> certificates = extractCertificates(signedData); ASN1Set signerInfosAsn1 = signedData.getSignerInfos(); logger.info("SIGNER INFO ASN1 : " + signerInfosAsn1.toString()); SignerInfo signedInfo = SignerInfo.getInstance(ASN1Sequence.getInstance(signerInfosAsn1.getObjectAt(0))); ASN1Set authenticatedAttributeSet = signedInfo.getAuthenticatedAttributes(); logger.info("AUTHENTICATED ATTR : " + authenticatedAttributeSet); List<ASN1ObjectIdentifier> attributeOids = new ArrayList<ASN1ObjectIdentifier>(); for (int i = 0; i < authenticatedAttributeSet.size(); i++) { Attribute attribute = Attribute.getInstance(authenticatedAttributeSet.getObjectAt(i)); attributeOids.add(attribute.getAttrType()); } logger.info("List of OID for Auth Attrb : " + attributeOids); Attribute attributeDigest = Attribute.getInstance(authenticatedAttributeSet.getObjectAt(1)); assertEquals(PKCSObjectIdentifiers.pkcs_9_at_messageDigest, attributeDigest.getAttrType()); ASN1OctetString asn1ObjString = ASN1OctetString.getInstance(attributeDigest.getAttrValues().getObjectAt(0)); String embeddedDigest = Base64.encode(asn1ObjString.getOctets()); logger.info("MESSAGE DIGEST : " + embeddedDigest); byte[] digestSignedContent = DSSUtils.digest(digestAlgorithm, signedContent); String computedDigestSignedContentEncodeBase64 = Base64.encode(digestSignedContent); logger.info( "COMPUTED DIGEST SIGNED CONTENT BASE64 : " + computedDigestSignedContentEncodeBase64); assertEquals(embeddedDigest, computedDigestSignedContentEncodeBase64); SignerIdentifier sid = signedInfo.getSID(); logger.info("SIGNER IDENTIFIER : " + sid.getId()); IssuerAndSerialNumber issuerAndSerialNumber = IssuerAndSerialNumber.getInstance(signedInfo.getSID()); ASN1Integer signerSerialNumber = issuerAndSerialNumber.getSerialNumber(); logger.info( "ISSUER AND SN : " + issuerAndSerialNumber.getName() + " " + signerSerialNumber); BigInteger serial = issuerAndSerialNumber.getSerialNumber().getValue(); X509Certificate signerCertificate = null; for (X509Certificate x509Certificate : certificates) { if (serial.equals(x509Certificate.getSerialNumber())) { signerCertificate = x509Certificate; } } assertNotNull(signerCertificate); String algorithm = signerCertificate.getPublicKey().getAlgorithm(); EncryptionAlgorithm encryptionAlgorithm = EncryptionAlgorithm.forName(algorithm); ASN1OctetString encryptedInfoOctedString = signedInfo.getEncryptedDigest(); String signatureValue = Hex.toHexString(encryptedInfoOctedString.getOctets()); logger.info("SIGNATURE VALUE : " + signatureValue); Cipher cipher = Cipher.getInstance(encryptionAlgorithm.getName()); cipher.init(Cipher.DECRYPT_MODE, signerCertificate); byte[] decrypted = cipher.doFinal(encryptedInfoOctedString.getOctets()); ASN1InputStream inputDecrypted = new ASN1InputStream(decrypted); ASN1Sequence seqDecrypt = (ASN1Sequence) inputDecrypted.readObject(); logger.info("DECRYPTED : " + seqDecrypt); DigestInfo digestInfo = new DigestInfo(seqDecrypt); assertEquals(oidDigestAlgo, digestInfo.getAlgorithmId().getAlgorithm()); String decryptedDigestEncodeBase64 = Base64.encode(digestInfo.getDigest()); logger.info("DECRYPTED BASE64 : " + decryptedDigestEncodeBase64); byte[] encoded = authenticatedAttributeSet.getEncoded(); byte[] digest = DSSUtils.digest(digestAlgorithm, encoded); String computedDigestFromSignatureEncodeBase64 = Base64.encode(digest); logger.info( "COMPUTED DIGEST FROM SIGNATURE BASE64 : " + computedDigestFromSignatureEncodeBase64); assertEquals(decryptedDigestEncodeBase64, computedDigestFromSignatureEncodeBase64); IOUtils.closeQuietly(inputDecrypted); IOUtils.closeQuietly(asn1sInput); } IOUtils.closeQuietly(inputStream); document.close(); } catch (Exception e) { logger.error(e.getMessage(), e); fail(e.getMessage()); } }
private List<PdfSignatureOrDocTimestampInfo> getSignatures( CertificatePool validationCertPool, byte[] originalBytes) { List<PdfSignatureOrDocTimestampInfo> signatures = new ArrayList<PdfSignatureOrDocTimestampInfo>(); ByteArrayInputStream bais = null; PDDocument doc = null; try { bais = new ByteArrayInputStream(originalBytes); doc = PDDocument.load(bais); List<PDSignature> pdSignatures = doc.getSignatureDictionaries(); if (CollectionUtils.isNotEmpty(pdSignatures)) { logger.debug("{} signature(s) found", pdSignatures.size()); PdfDict catalog = new PdfBoxDict(doc.getDocumentCatalog().getCOSDictionary(), doc); PdfDssDict dssDictionary = PdfDssDict.extract(catalog); for (PDSignature signature : pdSignatures) { String subFilter = signature.getSubFilter(); byte[] cms = signature.getContents(originalBytes); if (StringUtils.isEmpty(subFilter) || ArrayUtils.isEmpty(cms)) { logger.warn("Wrong signature with empty subfilter or cms."); continue; } byte[] signedContent = signature.getSignedContent(originalBytes); int[] byteRange = signature.getByteRange(); PdfSignatureOrDocTimestampInfo signatureInfo = null; if (PdfBoxDocTimeStampService.SUB_FILTER_ETSI_RFC3161.getName().equals(subFilter)) { boolean isArchiveTimestamp = false; // LT or LTA if (dssDictionary != null) { // check is DSS dictionary already exist if (isDSSDictionaryPresentInPreviousRevision( getOriginalBytes(byteRange, signedContent))) { isArchiveTimestamp = true; } } signatureInfo = new PdfBoxDocTimestampInfo( validationCertPool, signature, dssDictionary, cms, signedContent, isArchiveTimestamp); } else { signatureInfo = new PdfBoxSignatureInfo( validationCertPool, signature, dssDictionary, cms, signedContent); } if (signatureInfo != null) { signatures.add(signatureInfo); } } Collections.sort(signatures, new PdfSignatureOrDocTimestampInfoComparator()); linkSignatures(signatures); for (PdfSignatureOrDocTimestampInfo sig : signatures) { logger.debug( "Signature " + sig.uniqueId() + " found with byteRange " + Arrays.toString(sig.getSignatureByteRange()) + " (" + sig.getSubFilter() + ")"); } } } catch (Exception e) { logger.warn("Cannot analyze signatures : " + e.getMessage(), e); } finally { IOUtils.closeQuietly(bais); IOUtils.closeQuietly(doc); } return signatures; }