English:encryption
Kadu
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Basic informations
Encryption module is used to run encrypted conversations using OpenSSL, which is required for the module to compile.
Person whom we speak with also need to have a communicator capable of handling encrypted conversations. Encryption module is compatible with EKG communicator, and also with an encryption plug-in for PowerGG.
Using the module
If you don't have a pair of your own keys yet, you should generate them. You can do it by using a Generate keys button in the Chat part of the Kadu configuration. All keys are being held in the ~/.kadu/keys directory. To send someone our public key you have to find the person on the userlist and in the context menu select an option Send my public key. To recieve someone's public key we have to make sure that the option Use encryption in Configuration/Chat is on. Encrypted messages are shown using a different color, which you can change in the options. To temporarily diable encryption just use the padlock icon in the chat window.
Attention Disabling 'Use encryption; still allows to read encrypted messages. Using a padlock icon you can temporarily enable it.
Moving keys
If you plan to use your keys in other communicators read this paragraph
Like i said, keys are being held in ~/.kadu/keys. If we are moving them to another program like for example EKG, being on another computer, just create the same directory there and copy all the files. If you want to move keys to the windows environment remember about the differences in the end line characters. Useful programs for conversion: todos and fromdos.
Idea of private and public keys
RSA cipher algorithm is based on on an idea of using a pair of keys. Each user has 2 types of keys: a private key and a public key. Only the owner should have an access to the private key, but the public key may(or even should) be distributed to others.
Imagine a situation where there are three people - Adam would like to send Bonifacy an encrypted message, but there is a mysterious Spy who can eavesdrop the conversation. If they use a traditional method of cyphering (1 key, which is used both to code and decode messages), the Spy can get the key, he could then get all the information without any problem. Now if they use an algorithm based on two keys, the situation gets complicated. Adam and Bonifacy generate their keys, nextly they share the public ones(which was surely noticed by the Spy). Adam creates an encrypted message using his private key and Bonifacy's public key. Such a cyphered message could be decrypted only by a Bonifacy's private key and Adam's public key. So as we can see, any Spy who doesn't have an access to the private keys(which we do not share) cannot read our messages.
