Your RSA key is too small. or This CSR Uses An Unsupported Key Size
When I am purchasing or replacing my certificate I get the error:
Your RSA key is too small! or This CSR uses an unsupported key size.
For all certificates that Comodo issues (including EV SSL), the RSA key size MUST BE at least 2048-bit as of 20-DEC-2010. To resolve this error please regenerate your CSR with the key size of 2048 and try again.
Note: To retain maximum compatibility across all browsers do not use an RSA key size of over 2048 at this time!