Re: Signing the hash of the signer's certficate

[Jean-Marc Desperrier <jmdesp@xxxxxxx>]

Anders Rundgren wrote:

> It seems that neither CMS nor XML Dsig explicitly
> support signing the hash of the signer's certificate.
>  
It was not included directly inside RFC2630, but inside a RFC that 
followed it shortly : RFC2634.

The extension can be placed as a signed attribute inside any CMS or 
pkcs#7 message.

> I understand that the reason for this addition was to thwart
> changing the client certificate.
>
> However, there must be a considerable difficulty
> finding a client certificate with an identical public key
>  
Read RFC2634 chapter 5 and you will see the true reasons why this should 
be done :

http://www.zvon.org/tmRFC/RFC2634/Output/chapter5.html