Subject: RE: Update request for RFC3279 and 4055

From: "Rajesh Lachman" <[email-masked]>
Date: Thu, 29 Mar 2007 11:25:13 +0200

plain-text

Rajesh

_______________________________________________
Ir. R. Lachman
Adviseur PKIoverheid 
GBO.Overheid
Afdeling Beheer
Wilhelmina van Pruisenweg 104
Postbus 84011           
2508 AA Den Haag 
Tel: +31(0) 70 8887 950
Fax:+31(0) 70 8887 882
mailto: [email-masked]
Internet: www.gbo.overheid.nl  

-----Oorspronkelijk bericht-----
Van: Paul Hoffman [mailto:[email-masked]]
Verzonden: woensdag 28 maart 2007 19:43
Aan: Rajesh Lachman; [email-masked]
CC: [email-masked]
Onderwerp: Re: Update request for RFC3279 and 4055

At 3:34 PM +0200 3/28/07, Rajesh Lachman wrote:
>smime 1.p7m

Please send plain-text messages to the WG mailing list. This message 
is not readable by many people.

--Paul Hoffman, Director
--VPN Consortium

-----------

Dear, 

Introduction 

The Dutch governmental PKI (hereafter PKIoverheid) is the name for the Public Key Infrastructure designed for trustworthy electronic communication within and with the Dutch government. PKIoverheid does not issue certificates directly to end-users, but only issues certificates to so-called Certificate Service Providers (CSP). The Ministry of the Interior and Kingdom Relations is the owner of PKIoverheid. The Policy Authority PKIoverheid supports the Dutch Minister of the Interior and Kingdom Relations with the management and control of the PKI system.

Problem identification 
In 2005 crypto experts found weaknesses in the hash function SHA-1, and since then NIST (creator of SHA-1) has made the recommendation that SHA-1 should only be used until 2010. However, it's probably a good idea to start implementing a better hashing algorithm before a more serious vulnerability is found.

PKIoverheid wants to migrate its root infrastructure to SHA-256 based certificates. However, PKIoverheid discovered that these certificates can not be completely based on SHA-2 with current software conforming to RFC 3279 and RFC 4055. When creating a certificate based on SHA-2, then the thumbprint/fingerprint will still be SHA-1.

Proposed solution 
In "RFC 3279 Algorithms and Identifiers for the Internet X.509 Public Key Infrastructure April 2002, [Page 3]" 
Current text:
"This section identifies one-way hash functions for use in the Internet X.509 PKI. One-way hash functions are also called message digest algorithms. SHA-1 is the preferred one-way hash function for the Internet X.509 PKI. "

Replace with:
"This section identifies one-way hash functions for use in the Internet X.509 PKI. One-way hash functions are also called message digest algorithms. Hash functions from the SHA-family (SHA-1 or SHA-2) are preferred for one-way hash functions for the Internet X.509 PKI. 

When using one of these RSA signature algorithms, the same one-way hash function MUST be employed for the hashAlgorithm and the maskGenAlgorithm."

In "RFC 4055 Additional RSA Algorithms and Identifiers June 2005, [Page 23/24]" 

Current text:
"When using RSASSA-PSS, the same one-way hash function should be employed for the hashAlgorithm and the maskGenAlgorithm, but it is not required. When using RSAES-OAEP, the same one-way hash function should be employed for the hashFunc and the maskGenFunc, but it is not required. In each case, using the same one-way hash function helps with security analysis and reduces implementation complexity." 

Replace with:
"When using RSASSA-PSS, the same one-way hash function MUST be employed for the hashAlgorithm and the maskGenAlgorithm. When using RSAES-OAEP, the same one-way hash function MUST be employed for the hashFunc and the maskGenFunc. In each case, using the same one-way hash function helps with security analysis and reduces implementation complexity." 

Result:
When using the SHA-2 Signature algorithm within an X.509 certificate it is now required to use the same algorithm for the one-way hash function, thus resulting in a certificate with a message digest (thumbprint/fingerprint) algorithm field with the value "sha2".

Greetings, 

Rajesh 

_______________________________________________ 
Ir. R. Lachman 
Adviseur PKIoverheid 
GBO.Overheid 
Afdeling Beheer 
Wilhelmina van Pruisenweg 104 
Postbus 84011           
2508 AA Den Haag 
Tel: +31(0) 70 8887 950 
Fax:+31(0) 70 8887 882 
mailto: [email-masked] 
Internet: www.gbo.overheid.nl