Hello

Jacob Bachmeyer schrieb am 2024-12-06:

> Better solution:  never sign a document exactly as presented to you; always 
> make a small change first. This could be as simple as including a nonce in 
> the signature.  

Correct – if the change or nonce is big and random enough (at least about 80 
bit of randomness to compensate for the lost 80 bits of security due to the 
birthday attack, even if that is not a real compensation for multiple reasons), 
i.e. make many small or few big changes to the content. But the normal user 
does not know.

> This is from Schneier's /Applied Cryptography/ from many years ago:  this 
> problem (and its solution) is old.

Absolutely correct. It is a great book.

But most people do not even see the problem.

Best regards
-- 
Rainer Perske
Systemdienste + Leiter der Zertifizierungsstelle (UCAM)
-- 
Universität Münster
CIT - Center for Information Technology
Rainer Perske, Systemdienste
Röntgenstraße 7-13, Raum 006
48149 Münster
Tel.: +49 251 83-31582
E-Mail: [email protected]
Website: www.uni-muenster.de/IT

Universitätszertifizierungsstelle Münster (UCAM):
Tel.: +49 251 83-31590
E-Mail: [email protected]
WWW: www.uni-muenster.de/CA

YouTube: youtube.com/@uni_muenster
Instagram: instagram.com/uni_muenster
LinkedIn: linkedin.com/school/university-of-muenster
Facebook: facebook.com/unimuenster

Attachment: smime.p7s
Description: S/MIME cryptographic signature

_______________________________________________
Gnupg-devel mailing list
[email protected]
https://lists.gnupg.org/mailman/listinfo/gnupg-devel

Reply via email to