PdfReader reader = new PdfReader("c:\\sss.pdf");
		AcroFields fields = reader.getAcroFields();
		for (String signame : fields.getSignatureNames()) {
			System.out.println(signame);
			PdfDictionary sig = fields.getSignatureDictionary(signame);
			System.out.println(sig.getAsString(PdfName.REASON));
		}

This is a code snippet that retrieves the signatures from a pdf document and the reason for them. It does that in approximately 200ms for one signature.

Get a pdf signature with iTExt 5.3

java

Java