Subject: TSA Response serialNumber Field

From: [email-masked]
Date: Thu, 18 May 2000 08:44:20 -0400

Salut Denis,

I do not remember if this issue was raised before, but although I understand
that there is no limit on the size of an Integer value, the "serialNumber"
field of a time stamping response in Section 2.4.2 will ultimately become an
enormously large number over the life of a TSA that is issuing numerous time
stamps per second.

Would it not be more sensible for the serialNumber field to optionally be a
monotonically increasing integer from one TimeStampToken to the next within
a fixed period of time specified by the TSA's policy (e.g. a week, a day, an
hour, etc.)?

Such a serialNumber with the appropriate period of time would still provide
a way to build a unique identifier to reference a time stamp token.

Francois
___________________________________
Francois Rousseau
Director of Standards and Conformance
Chrysalis-ITS
1688 Woodward Drive
Ottawa, Ontario, CANADA, K2C 3R7
[email-masked]      Tel. (613) 723-5076 ext. 419
http://www.chrysalis-its.com     Fax. (613) 723-5078

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From: Denis Pinkas <[email-masked]>
Date: Thu, 18 May 2000 15:20:04 +0200

> enormously large number over the life of a TSA that is issuing numerous time

I do not see a problem here. We do not have a limitation for
serialNumber in a public key certificate.
In our case, 64 bits would be quite enough, while 32 bits would be
too small.

To accomodate your issue we could add a comment in the ASN1 for the
serialNumber saying:

-- Time Stamps users must be ready to accomodate integers up to 64
bits.

> a fixed period of time specified by the TSA's policy (e.g. a week, a day, an

I do not think so.

> a way to build a unique identifier to reference a time stamp token.

But such an identifier would be much longer. :-(

Thanks for your comment,

Denis

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From: Paul Koning <[email-masked]>
Date: Thu, 18 May 2000 10:09:03 -0400 (EDT)

>>>>> "FRousseau" == FRousseau  <[email-masked]> writes:

 FRousseau> Salut Denis, I do not remember if this issue was raised
 FRousseau> before, but although I understand that there is no limit
 FRousseau> on the size of an Integer value, the "serialNumber" field
 FRousseau> of a time stamping response in Section 2.4.2 will
 FRousseau> ultimately become an enormously large number over the life
 FRousseau> of a TSA that is issuing numerous time stamps per second.

64 bits is not that large, and will last more than long enough.

In network management, 64 bit counters are often used because you can
make a byte counter on a high speed link 64 bits and never have to
worry about wrapping it.  So clearly it's good enough for this
application. 

 FRousseau> Would it not be more sensible for the serialNumber field
 FRousseau> to optionally be a monotonically increasing integer from
 FRousseau> one TimeStampToken to the next within a fixed period of
 FRousseau> time specified by the TSA's policy (e.g. a week, a day, an
 FRousseau> hour, etc.)?

 FRousseau> Such a serialNumber with the appropriate period of time
 FRousseau> would still provide a way to build a unique identifier to
 FRousseau> reference a time stamp token.

Yes, but it would be a very different thing and if such a field is
included it really should have a different name.

	 paul