Examples with GetRevisionResult com.amazonaws.services.qldb.model.GetRevisionResult used on opensource projects

Example 1 with GetRevisionResult

use of com.amazonaws.services.qldb.model.GetRevisionResult in project amazon-qldb-dmv-sample-java by aws-samples.

the class GetRevision method verifyRegistration.

/**
 * Verify each version of the registration for the given VIN.
 *
 * @param driver
 *              A QLDB driver.
 * @param ledgerName
 *              The ledger to get digest from.
 * @param vin
 *              VIN to query the revision history of a specific registration with.
 * @throws Exception if failed to verify digests.
 * @throws AssertionError if document revision verification failed.
 */
public static void verifyRegistration(final QldbDriver driver, final String ledgerName, final String vin) throws Exception {
    log.info(String.format("Let's verify the registration with VIN=%s, in ledger=%s.", vin, ledgerName));
    try {
        log.info("First, let's get a digest.");
        GetDigestResult digestResult = GetDigest.getDigest(ledgerName);
        ValueHolder digestTipAddress = digestResult.getDigestTipAddress();
        byte[] digestBytes = Verifier.convertByteBufferToByteArray(digestResult.getDigest());
        log.info("Got a ledger digest. Digest end address={}, digest={}.", QldbStringUtils.toUnredactedString(digestTipAddress), Verifier.toBase64(digestBytes));
        log.info(String.format("Next, let's query the registration with VIN=%s. " + "Then we can verify each version of the registration.", vin));
        List<IonStruct> documentsWithMetadataList = new ArrayList<>();
        driver.execute(txn -> {
            documentsWithMetadataList.addAll(queryRegistrationsByVin(txn, vin));
        });
        log.info("Registrations queried successfully!");
        log.info(String.format("Found %s revisions of the registration with VIN=%s.", documentsWithMetadataList.size(), vin));
        for (IonStruct ionStruct : documentsWithMetadataList) {
            QldbRevision document = QldbRevision.fromIon(ionStruct);
            log.info(String.format("Let's verify the document: %s", document));
            log.info("Let's get a proof for the document.");
            GetRevisionResult proofResult = getRevision(ledgerName, document.getMetadata().getId(), digestTipAddress, document.getBlockAddress());
            final IonValue proof = Constants.MAPPER.writeValueAsIonValue(proofResult.getProof());
            final IonReader reader = IonReaderBuilder.standard().build(proof);
            reader.next();
            ByteArrayOutputStream baos = new ByteArrayOutputStream();
            IonWriter writer = SYSTEM.newBinaryWriter(baos);
            writer.writeValue(reader);
            writer.close();
            baos.flush();
            baos.close();
            byte[] byteProof = baos.toByteArray();
            log.info(String.format("Got back a proof: %s", Verifier.toBase64(byteProof)));
            boolean verified = Verifier.verify(document.getHash(), digestBytes, proofResult.getProof().getIonText());
            if (!verified) {
                throw new AssertionError("Document revision is not verified!");
            } else {
                log.info("Success! The document is verified");
            }
            byte[] alteredDigest = Verifier.flipRandomBit(digestBytes);
            log.info(String.format("Flipping one bit in the digest and assert that the document is NOT verified. " + "The altered digest is: %s", Verifier.toBase64(alteredDigest)));
            verified = Verifier.verify(document.getHash(), alteredDigest, proofResult.getProof().getIonText());
            if (verified) {
                throw new AssertionError("Expected document to not be verified against altered digest.");
            } else {
                log.info("Success! As expected flipping a bit in the digest causes verification to fail.");
            }
            byte[] alteredDocumentHash = Verifier.flipRandomBit(document.getHash());
            log.info(String.format("Flipping one bit in the document's hash and assert that it is NOT verified. " + "The altered document hash is: %s.", Verifier.toBase64(alteredDocumentHash)));
            verified = Verifier.verify(alteredDocumentHash, digestBytes, proofResult.getProof().getIonText());
            if (verified) {
                throw new AssertionError("Expected altered document hash to not be verified against digest.");
            } else {
                log.info("Success! As expected flipping a bit in the document hash causes verification to fail.");
            }
        }
    } catch (Exception e) {
        log.error("Failed to verify digests.", e);
        throw e;
    }
    log.info(String.format("Finished verifying the registration with VIN=%s in ledger=%s.", vin, ledgerName));
}