Which of the following practices are important for the security of private keys?

Which of the following practices are important for the security of private keys?

(Choose TWO correct answers.)
A . Private keys should be created on the systems where they will be used and should never leave them.
B . Private keys should be uploaded to public key servers.
C . Private keys should be included in X509 certificates.
D . Private keys should have a sufficient length for the algorithm used for key generation.
E . Private keys should always be stored as plain text files without any encryption.

Answer: C D