2005年12月16日 星期五

SSL

SSL (Secure Socket Layer)
* Using Digital Certificate, Digital Signature, Public Key Encryption, Hash (Message Digest)
* Instead of encrypting the sender's original text, only the session key generated by the sender is encrypted by the receiver's public key.
* The session key is valid throughout a session and not any longer.
* SSL is proposed by Netscape, Inc.
* https is actually http enhanced by SSL. https uses port 443 while http uses port 80.

Lab SSL

1. Try Yam membership enrollment
for using SSL encrypted Internet communications.
2. Note the lock at the lower right corner is secured when SSL is enabled.
3. Click the lock icon and a message window should pop up.
4. What kind of encryption is used in this SSL? How many bits are there in the encryption key?
5. Who issued the certificate you are seeing? (Who is the certificate authority, CA, for this website?)
6. Until when is the certificate valid?
7. What kind(s) of hash is/are used in the CA's digital signature?
8. How many bits are there in the hash(es)?

Lab PGP II

1. Sign a file. Send this file to Friend A & Friend B. Verify that both of them can read your signature.

2. Sign a file and encrypt this file and signature using A's public key. Email it to A and B. What will happen?