What's the difference between class 1 and class 3 roots, and the certificates signed by them?

Question

Pretty much what the question says. What's the difference between the two classes of roots? The differences between the certificates signed by such roots? What uses would a class 1 signed certificate have that a class 3 doesn't, and vice versa?

Answer 1

The class 3 root certificate is the high-security subset of the CAcert class 1 root certificate.

Class 1 is the 'normal' and older root certificate of CAcert. It includes both, low security and high security certificates. As it might not be possible to get the class 1 certificate included into some browsers or distributions, the Class 3 certificate was introduced. The Class 3 root certificate includes only high security certificates and is a subset of the Class 1 certificate.

In general: The class 3 will probably be integrated into more browsers and distributions in the future, whereas the class 1 certificate probably works with more and especially older browsers.

(See http://www.luga.at/mailing-lists/luga/2006/02/msg00109.html)