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Elektra
0.9.8
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Elektra can protect the following aspects of your configuration:
Elektra provides two plugins to achieve this protection:
crypto, andfcrypt.For the rest of this tutorial we assume that you are somewhat familiar with GnuPG (GPG). The documentation of GnuPG can be found here.
In order to find your GPG private key(s) you can use:
If GPG private keys are available, you see an output, that looks similar to this:
The GPG key we use in this tutorial has the ID DDEBEF9EE2DC931701338212DAF635B17F230E8D.
A GPG private key is mandatory for the plugins to work. If you have no GPG private key available, you can generate one by entering the following command:
The fcrypt plugin and the crypto plugin support both versions (version 1 and version 2) of GPG.
In this tutorial we explain the use of the crypto plugin and the fcrypt plugin by a simple example: We want to protect a password that is contained in an INI-file.
The following example demonstrates how the INI-file is mounted without encryption enabled. We create the password at user:/tests/password and display the contents of test.ini.
Step 1: Mount test.ini
Step 2: Set the password at user:/tests/password and display the contents of test.ini
Step 3: (Optional) Cleanup
As you can see the password is stored in plain text. In this tutorial we demonstrate two different approaches towards confidentiality:
fcrypt plugin, which encrypts the entire INI-file, andcrypto plugin, which allows the encryption of specific key values only.We also show how to approach integrity with the signature features of the fcrypt plugin.
The fcrypt plugin enables the encryption and decryption of entire configuration files, thus protecting the confidentiality of the configuration keys and values. fcrypt utilizes GPG for all cryptographic operations. The GPG key, which is used for encryption and decryption, is specified in the backend configuration under encrypt/key.
If the above command fails, please take a look at the ReadMe of the fcrypt plugin.
As a result the file test.ini is encrypted using GnuPG. fcrypt will call the gpg2 or gpg binary as follows:
Note that test.ini can not only be decrypted by Elektra, but it is also possible to decrypt it with GnuPG directly. You can try to decrypt test.ini with GPG:
The complete procedure looks like this:
To clean up the environment we run:
fcrypt also offers the option to sign and verify configuration files, thus protecting the integrity of the configuration values. If sign/key is specified in the backend configuration, fcrypt will forward the key ID for signing the configuration file.
An example backend configuration is given as follows:
As a result the file test.ini will be signed using GPG. fcrypt will call the gpg2 or gpg binary as follows:
If test.ini is modified, all following calls of kdb get will fail with an error message stating that the signature of the file could not be verified.
The complete example looks like this:
To clean up the environment we run:
The options sign/key and encrypt/key can be combined together, resulting in configuration files, that are signed and encrypted.
Mounting test.ini with signatures and encryption enabled can be done like this:
The complete example looks like this:
To clean up the environment we run:
So far we learned how to encrypt and decrypt entry configuration files. Sometimes we only want to protect a smaller subset of configuration values in a bigger configuration setting. For this reason the crypto plugin was developed.
The crypto plugin uses libgcrypt as provider of cryptographic functions.
The crypto plugin provides the option to encrypt and decrypt single configuration values (Keys) in a Keyset. GPG is required for the key-handling.
To follow our example of an encrypted password in test.ini, we first mount the INI-file with the crypto plugin enabled, like this:
We recommend adding the base64 plugin to the backend, because crypto will output binary data. Having binary data in configuration files is hardly ever feasible. base64 encodes all binary values within a configuration file and transforms them into Base64 strings.
To tell the crypto plugin which Keys it should process, the metakey crypto/encrypt is used. The crypto plugin searches for the metakey crypto/encrypt. If the value is equal to 1, the value of the Key will be encrypted.
We want to protect the password, that is stored under user:/test/password. So we set the metakey as follows:
Now we are safe to set the actual password:
The resulting INI-file contains the following data:
You can access the password as usual with kdb get:
As a result you get "1234".
You can disable the encryption by setting crypto/encrypt to a value other than 1, for example:
The complete example looks like this:
To disable encryption on user:/tests/password, we can run:
To clean up the environment we run:
To shut down the gpg-agent we run:
The shutdown of gpg-agent is optional.
1.9.1