Chapter 15. Encryption with KGpg

SUSE LINUX – User Guide Part IV. Internet / Chapter 15. Encryption with KGpg
	14.3. Preferences		15.2. The Key Server Dialog

Table of Contents

15.1. Key Management
15.2. The Key Server Dialog
15.3. The Applet
15.4. For More Information

Abstract

KGpg is an important component of the encryption infrastructure on your system. With the help of this program, generate and manage all needed keys, use its editor function for the quick creation and encryption of files, or use the applet in your panel to encrypt or decrypt by dragging and dropping. The generation and management of keys is required for other applications, such as KMail or Konqueror, to handle encrypted files or e-mail messages correctly. This chapter covers the basic functions needed for daily work with encrypted files.

15.1. Key Management

This section covers operations needed for handling your digital key ring. Other programs, such as your mail program (KMail or Evolution), access the managed key data to process signed or encrypted contents.

15.1.1. Generating a New Key Pair

To be able to exchange encrypted messages with other users, first generate your own key pair. One part of it — the public key — is distributed to your communication partners, who can use it to encrypt the files or e-mail messages they send. The other part of the key pair — the secret key — is used to decrypt the encrypted contents.

	Important
The public key is intended for the public and is distributed to all of your communication partners. However, only you should have access to the secret key. Do not grant other users access to this data.

Start KGpg from the main menu or with the command kgpg from the command line. A padlock icon for KGpg appears in your panel. Click the icon to open the function menu. Select ‘Open key manager’. Refer to Figure 15.1. “The Key Manager”. Under ‘Key’, access all options related to the generation or management of keys. To generate a new key pair for yourself, click ‘Generate Key Pair’ (Ctrl-N).

Figure 15.1. The Key Manager

In the following dialog, shown in Figure 15.2. “Generating Keys”, enter your user name, your e-mail address, and an optional comment. The default setting for ‘Expiration’ (Never — key pair is valid for an indefinite period) can be accepted unless you want your keys to expire after a certain time. The default settings for ‘Key size’ and ‘Algorithm’ can be accepted as they are. Now, start the key generation with ‘OK’. After this process is completed, the newly generated key appears in the overview window of the key manager.

Figure 15.2. Generating Keys

15.1.2. Exporting the Public Key

After generating your key pair, make the public key available to other users. This enables them to use it to encrypt or sign the messages or files they send you. To make the public key available for others, select ‘Keys’+‘Export Public Key’. The dialog that opens offers three options:

Export Public Key To Email: Your public key is sent to a recipient of your choice by e-mail. If you activate this option and confirm with ‘OK’, the dialog for creating a new e-mail message with KMail appears. Enter the recipient and click ‘Send’. The recipient will receive your key and can then send you encrypted contents.
Export Public Key To Clipboard: You can place your public key here before you continue to process it.
Export Public Key To File: If you prefer to distribute your key as a file on a data medium instead of sending it by e-mail, click this option, confirm or change the file path and name, and click ‘OK’.

To make your public key available to a wide audience, export it to one of the key servers on the Internet. For more information, refer to Section 15.2. “The Key Server Dialog”.

15.1.3. Importing Keys

If you receive a key in a file (for example, as an e-mail attachment), integrate it in your key ring with the feature ‘Import Key’ and use it for encrypted communication with the sender. The procedure is similar to the procedure for exporting keys described above.

15.1.4. Signing Keys

Keys can be signed to guarantee authenticity and integrity. If you are absolutely sure an imported key belongs to the individual specified as the owner, express your trust in the authenticity of the key by means of your signature.

	Important
Encrypted communication is only secure to the extent that you can positively associate public keys in circulation with the specified user. By cross-checking and signing these keys, you contribute to the establishment of a web of trust.

Select the key to sign in the key list. Select ‘Keys’+‘Sign Key’. In the following dialog, designate the secret key to use for the signature. An alert reminds you to check the authenticity of this key before you sign it. If you have performed this check, click ‘Yes’ and enter the password for the selected secret key in the next step. Other users can now check the signature by means of your public key.