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/*                 CS255    Project 2                                */
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I.   Group Info:

     He, Changhua     username: changhua      SUID: 5155486
     Jin, Weiyin      username: lucyjin	      SUID: 5157548



II.  Project Implementation:

Part A: Obtain Long-Term Cerficates
===================================

   We first generated four keystores from the command line by using the
"keytool -genkey -alias ... " command.  The four keystores correspond to the client,
the server, the privateCA, and the RegistrationCA.  At this stage, all
keystores only contain one entry which is the entity's key pair and the
self signed certificate.  We then used the "keytool -import ..." command
to import to each KeyStore the appropriate trusted entities.  Then we
called the RegCA() to generate a certificate for each of the online
entities. So the self-signed certificate of each entity is replaced by
the Registration CA's signed certificate.  

File Created: 
Chat/RegCA.java: public RegCA(String appKeyStoreName, String appPassword, String alias, String aliasPassword)
This function signs the entity with the given alias and appKeyStoreName
using its public key.

As a result, the KeyStores of client, server, and privateCA are modified.
Client and Server should each have one key-entry and 2 trusted entities,
namely Registration CA and the privacy CA.  The private CA should only have
Registration CA as the trusted entity, and finally the Registration CA
should only has its keyentry in the KeyStore.



Part B: Obtain Chat Certificates
================================

   We first established SSL connection between client<->PCA, client<->server,
and when offensive client appears, establish server<->PCA.  For the
implementation here, we just referred to the
SSL example code provided by the project description. Note, when a party
is making connection to another party, it uses its own keystore to
establish the keyManagerFactory and the TrustedManagerFactory.  So, upon
connection, each pair of parties will verify the validity of the
connecting party's certificate. The client waits for the PCA to
generate a ChatCertificate and then once the signed certificate is
generated, the client set that certificate in its own KeyStore using the
function setKeyEntry.  

On the PCA's side, when it is generating the chat certificate, it replace
the real name of the client by a random string which we call the
pseudonym. We generated the pseudonym by simply generating a random number
and convert it to a string.  The PCA also keeps a table with records of the client's real
identity with the corresponding pseudonym.  

Modified Files:
Chat/PCA.java
Chat/ChatClient.java
Chat/ChatServer.java
Chat/ChatServerThread.java



Part C: Revoke Certificates
===========================

   Upon established all connections and checking all necessary
certificates, we have a functioning system.  We defined the
word "bomb" as offensive, thus whenever the user types the word "bomb" we
took the following actions:

1. The server close the connection, and that word would not be displayed 
   in the Chat Room and will not be seen by other users.
2. The Server store the chat certificate of the client who sent this
   offensive word to its CRL and it will reject the future connection 
   with the same certificate.
4. Server sends over the pseudonym to the PCA.  
5. PCA looks up its table of record, figure out the corresponding real name
   of the offensive client.  
6. PCA adds the general purpose certificate that the client got from RCA to
   its CRL.
7. PCA will reject further chat certificate request from the same client
   by checking if that general purpose certificate is in its CRL. 

===========================================================================
We created the new MyX509TrustedManager interface out of the
TrustedManager, but with the added feature that we have to check to see if
the client is banned or not by checking in the CRL the certificate of
the client.  If it is banned, then we need to throw a certificate
exception indicating that it is banned.  

We replaced the original TrustedManager typed object in the SSL connection
with this new interface in all files where SSL connection is involved. 


Modified Files:
Chat/PCA.java
Chat/ChatServer.java
Chat/ClientRecord.java

Created Files:
Chat/myX509TrustedManager.java

Also the Makefile is modified accordingly whenever a new .java file is
created.