Get Message Digest Algorithm

MDAlgorithm.java

MessageDigest digest=MessageDigest.getInstance(signerInfo.getDigestAlgOID());
//Get Attribute
Attribute attribute1 =signerInfo.getSignedAttributes().get(PKCSObjectIdentifiers.pkcs_9_at_messageDigest);
Attribute attribute2=null;
if(signerInfo.getUnsignedAttributes()!=null)    {
    attribute2 =signerInfo.getUnsignedAttributes().get(PKCSObjectIdentifiers.id_aa_signatureTimeStampToken);
}
messageDigest=Base64.getEncoder().encodeToString(
                Hex.decode(attribute1.getAttributeValues()[0].toString().substring(1)));