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The OpenPGP functions can be used only if the unlimited key strength has been activated. You can find detailed pieces of information about the legal background for the deployment of cryptography on our website. With the Check Key Strength functionality you can determine the currently supported key strength of your Java environment. |
If you do not have generated own OpenPGP keys the Digester software provides functions to create some using a wizard dialog. The generated keys may also be imported by other programs with encryption functionality as long as OpenPGP-compatible keys are supported for import.
After the Create New Key menu has been selected a wizard dialog appears where you are prompted to setup the settings of the new key. In the first step the following pieces of information can be specified:
Name, comment, and e-mail address will be displayed by OpenPGP-compatible programs in the form "Real name (Comment) <E-Mail address>", for example "Leisenfels Development (temporary) <devel@leisenfels.com>" where name and e-mail is required and the comment may be omitted. In the key parameter section you may choose between the algorithms RSA or DH/DSS (DH=Diffie/Hellman). The key length must be specified in the range between 512 and 4096 bits while values less than 2048 should not be used any longer due to security reasons.
The input fields for name, comment, and e-mail remember their values in separate histories so that the values can be re-used for the next key generations. You can clear the histories with the context menues (right mouse button). Here you can also paste values from the clipboard or copy into clipboard for other programs.
In the second step of the wizard you can set the passphrase (password) for the new key:
After clicking the Finish button, the new OpenPGP key is generated based on your settings. This may take some seconds depending on the settings and depending on the computer speed. The button is only clickable if all values are consistent. The fields containing missing or faulty entries are highlighted as an indication. After the key generation has been completed a message is displayed by the status bar of the program. The new key may be used from this point by the program functions. If the passphrase has not been remembered permanently, you can store the passphrase at any time later using the key management. This is especially useful if signatures are generated from the command-line or from build scripts since no dialogs may be displayed to prompt for passphrases here.
If you already have OpenPGP keys then these may be imported with the Digester software. If you plan to generate signatures for FTP servers for example then you must import the secret keys. In order to do this the passphrase is required, too, which you can edit after the successful import of your key using the key management. The import of public keys is sufficient if you only plan to check signatures from the Internet. Here, you do not need a passphrase.
After the Import Keys menu has been selected a wizard dialog appears where you are prompted to select one or multiple keystore files. Usually OpenPGP keys are saved to files with the .asc or .sig extensions, other extensions may be possible. If confirmed with Next the selected files are being analyzed for usable keys which are presented by a list. Please select the desired keys for import and confirm with the Finish button. When the import has been completed an appropriate message is displayed by the status bar of the program. The loaded keys may be used from this point by the program functions. You can store the passphrases at any time later using the key management. This is especially useful if signatures are generated from the command-line or from build scripts since no dialogs may be displayed to prompt for passphrases here.
In order to re-use OpenPGP keys with other programs with encryption functionality, you may export keys with the Digester software into files. Please consult the documentation of the software, if OpenPGP keys can be imported there.
After the Export Keys menu has been selected a wizard dialog appears where you are prompted to make some settings. Please select the keys you wish to export and confirm with the Next button. In the next step you have the following options:
In the next step you can choose the keystore file for the export. Usually OpenPGP keys are saved to files with the .asc or .sig extensions, other extensions may be possible. After confirmation with Finish the export takes place. If the keystore file already exists a dialog is displayed. When the export has been completed an appropriate message is displayed by the status bar of the program.
Since some countries have special laws and regulations to limit the import/export of cryptographic technologies the Digester software may be deployed only for strong encryption (key lengths up to 128 bits) by default. This behavior is managed by the Java environment and may be modified appropriately if allowed by the laws. For key lengths up to 128 bits the OpenPGP functionality is switched off, since longer keys lengths are required here.
You may check the current crypto settings of your Java envirnoment easily by calling the Check Key Strength menu. If the key length is not limited then an appropriate message is displayed by the status bar of the program. The OpenPGP functions found in the OpenPGP menu can be used without restrictions here. If your Java environment is currently limited to key lengths up to 128 bits then a dialog with further information is being displayed. With the Install & Restart button you can let the software make the required modifications for the Java environment automatically. You are advised to consult your lawyer or local authorities in questions of cryptographic restrictions in your country. Please enable the unlimited key strength only if you have checked the legal situation in advance.
If the Java environment has been successfully configured to use unlimited key strength then
the software is restarted. Afterwards you can use the OpenPGP functionality without
restrictions. If the modifications cannot be executed due to missing permissions on your
computer the dialog must be closed with the Cancel button. Please ask your system
administrator to implement the required modifications which are explained on our website for the
recent Java versions. Two files have to be replaced by appropriate files from a ZIP archive
which can be downloaded directly from the Java manufacturer's website.
Currently OpenPGP keys are used internally by the Digester software e.g. by the generate window to calculate signatures based on the OpenPGP standard. The OpenPGP keys can be managed comfortably with a special dialog of the Digester software. In the center of the dialog you can see a table with available OpenPGP keys showing the Key Id, Name, eMail, Created (date and time), and Expire (date). In addition to that the table shows which functions may be used for the keys. If a secret key exists, then signatures can be generated and encrypted data can be decrypted. Of only the public key is available then signatures can be verified and data can be encrypted. Data encryption and decryption is currently not suported by the Digester software. The Created column may show a pen symbol if a passphrase has been specified for the key which is only possible for secret keys.
Above the table you can find some buttons on the left side which can used to control the table display. The symbol with the down arrow allows to display an index column. The second symbol sets the column widths automatically so that the texts in the columns will be readable (without abbreviations). The symbol with the empty box deselects all entries in the table, the symbol with the green arrow in the box selects all table entries automatically.
The symbols on the right side above the table call the corresponding functions of the OpenPGP menu in the main menu. The plus symbol creates new OpenPGP keys. A detailed description can be found in the Create New Key section.
The symbol with the pen may be used to set passphrases for the keys. Please select the OpenPGP key in the table and then click the pen symbol. Alternatively you can double-click the table entry. A dialog is then opened where you are prompted to enter or modify the passphrase. Set the Show cleartext option to be able to read your input directly. Please confirm your settings with the OK button, an empty input field resets the passphrase.
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Passphrases may be shown as cleartext only if entered the first time due to security reasons. |
With the red X symbol you can delete the selected keys from the list. If you accidentally deleted keys then please abort the dialog using the Cancel button and call the dialog again. The previous keys will be visible again. It makes sense to create key backups from time to time. You can use the export function for this. In order to transfer keys from one PC to another you can use the import function. Both functions may be called alternatively from the key management dialog (folder and diskette symbols).
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OpenPGP keys represent valuable and critical data which has to be handled with care and should be kept in a safe place. Create backups of your keys from time to time and keep the keystore files at a safe location like a bank vault. Do never write down passphrases and allow access to keys and passphrases only for entitled people. |
The OpenPGP key management may also be called from the tool bar with a button. The button functions on the right side above the table may alternatively be called from the context menu (right mouse button) where the selected keys are being processed.