import org.bouncycastle.tsp.TimeStampTokenInfo; //导入依赖的package包/类
DigestCalculator getMessageImprintDigestCalculator(DigestCalculatorProvider calculatorProvider)
    throws OperatorCreationException
{
    TimeStampToken token;

    try
    {
        token = this.getTimeStampToken(timeStamps[0]);

        TimeStampTokenInfo info = token.getTimeStampInfo();
        ASN1ObjectIdentifier algOID = info.getMessageImprintAlgOID();

        DigestCalculator calc = calculatorProvider.get(new AlgorithmIdentifier(algOID));

        initialiseMessageImprintDigestCalculator(calc);

        return calc;
    }
    catch (CMSException e)
    {
        throw new OperatorCreationException("unable to extract algorithm ID: " + e.getMessage(), e);
    }
}
 

import org.bouncycastle.tsp.TimeStampTokenInfo; //导入依赖的package包/类
/**
 * Checks if the {@code TimeStampToken} matches the signed data.
 *
 * @param data
 *            the array of {@code byte} representing the timestamped data
 * @return true if the data is verified by the TimeStampToken
 */
public boolean matchData(final byte[] data) {

	try {
		processed = true;
		messageImprintData = data != null;
		final TimeStampTokenInfo timeStampInfo = timeStamp.getTimeStampInfo();
		final ASN1ObjectIdentifier hashAlgorithm = timeStampInfo.getHashAlgorithm().getAlgorithm();
		final DigestAlgorithm digestAlgorithm = DigestAlgorithm.forOID(hashAlgorithm.getId());

		final byte[] computedDigest = DSSUtils.digest(digestAlgorithm, data);
		final byte[] timestampDigest = timeStampInfo.getMessageImprintDigest();
		messageImprintIntact = Arrays.equals(computedDigest, timestampDigest);
		if (!messageImprintIntact) {
			LOG.error("Computed digest ({}) on the extracted data from the document : {}", digestAlgorithm, Utils.toHex(computedDigest));
			LOG.error("Digest present in TimestampToken: {}", Utils.toHex(timestampDigest));
			LOG.error("Digest in TimestampToken matches digest of extracted data from document: {}", messageImprintIntact);
		}
	} catch (DSSException e) {
		messageImprintIntact = false;
	}
	return messageImprintIntact;
}
 

import org.bouncycastle.tsp.TimeStampTokenInfo; //导入依赖的package包/类
private void compareDigest(TimeStampToken timeStampToken, byte[] digest)
    throws ImprintDigestInvalidException
{
    TimeStampTokenInfo info = timeStampToken.getTimeStampInfo();
    byte[] tsrMessageDigest = info.getMessageImprintDigest();

    if (!Arrays.areEqual(digest, tsrMessageDigest))
    {
        throw new ImprintDigestInvalidException("hash calculated is different from MessageImprintDigest found in TimeStampToken", timeStampToken);
    }
}