Reliable Timestamps - Understanding the Format (rfc3161)

Question

[ edit : I wrote a blog postal address that explains everything in detail: see here ]

Hello!

I am desperately trying to create a service for reliable timestamps based on rfc3161. I decided to use the free trusted timestamp service at zeitstempel.dfn.de.

My question is: how to contact this service to get a valid answer. Regarding the request format, the RFC reports:

TimeStampReq ::= SEQUENCE { version INTEGER { v1(1) }, messageImprint MessageImprint, --a hash algorithm OID and the hash value of the data to be --time-stamped reqPolicy TSAPolicyId OPTIONAL, nonce INTEGER OPTIONAL, certReq BOOLEAN DEFAULT FALSE, extensions [0] IMPLICIT Extensions OPTIONAL } 

Where

  MessageImprint ::= SEQUENCE { hashAlgorithm AlgorithmIdentifier, hashedMessage OCTET STRING } 

I found a client that helped me a bit.

However, I still do not know how to create a request for the timestamp service.

Hello!

Answer 1

I'm glad you found our software useful. But you are referring to our old service. Visit www.ntp.org.pl - you will find there the latest version of the timestamping client and many other useful free programs related to the theme of time.

I'm not sure what you want to do. Maybe if you give a few details, I can help you better. In any case, I will give you some tips on where you can find valuable information.

First of all, you should look at the OpenSSL project: http://www.openssl.org/docs/apps/ts.html# There is an example of how to create a TSRequest. The request is stored in a file, so you can read its contents. You can later send a request to the server using this: http://www.openssl.org/docs/apps/tsget.html#

The entourage trick you can do is install some sniffer (for example, Wireshark - www.wireshark.org/), launch our client from the site www.ntp.org.pl, send a request, then find a suitable package in wirehark to watch what it contains.

Feel free to ask if you have further questions. Please provide additional information about your service.