We offered a complete set of ciphers, and recorded the ones shared with the server. Triple DES, RC2, RC4 and IDEA can all use keys of 128 bits or more, and are currently immune to exhaustive search of the possible keys to crack a message. Other methods of attacking ciphers depend on the details of the algorithm, and Triple DES is seen as a safe, conservative choice, since the DES algorithm has received in excess of twenty years of intense scrutiny. The validity period is an important part of the details contained within a certificate. By limiting the validity to a short period, the issuer reduces the likelihood of the data on which the certificate is based becoming obsolete, or a key contained in it becoming compromised.
Certificates also contain a unique serial number.
It identifies the organisation which issued the certificate, and therefore which public key should be used to check the signature on it.