Browser 
1. Find certificate of www.google.com find out which algorithms are used for hashing.
2. Download corresponding CRL. 
3. Open CRL and check its content.

Connecting to SSL Services (s_client)
4. Connect to www.fi.muni.cz. 
5. Check certificate path.
6. Connect to www.google.cz and save cert to GOOGLE.crt.

Format transformations (x509)
7. Decode certificate GOOGLE.crt.
8. Convert a certificate from PEM to DER format.
9. Convert a certificate from DER to PEM format.