A JavaCard key manager for Cryptsetup.

This is the repository of a school project for the PV204 course on the Faculty of Informatics of the Masaryk University in the term spring 2016.

Team B – Manoja Kumar Das, Ondrej Mosnáček, Mmabatho Idah Masemene

WARNING: This is a proof-of-concept project created by computer security students. Under no circumstances should it be considered secure for normal usage, unless it undergoes a proper review by security professionals :)

Host machine:

• Linux
• Cryptsetup
• JDK 1.8
• Apache Ant
• JUnit 4
• JCDK 2.2.2 (binaries included)
• JCardSim 3.0.4 (binary included)
• Bouncy Castle 1.54 (binary included)
• JCommander 1.49 (binary included)
• GlobalPlaformPro (binary included)
• NetBeans IDE 8 (for development)

Smart card:

• JavaCard 2.2.2 (for required algorithms see section Required JavaCard algorithms)

To use the application, use the scripts located in the scripts subdirectory. First, you will need to build the Java application for interacting with the JavaCard (JCKeyStorage):

$ cd scripts
$ ./build_application.sh
Trying to override old definition of task http://www.netbeans.org/ns/j2se-project/3:test-impl

BUILD SUCCESSFUL
Total time: 1 second

The other scripts need to know where JDK 1.8 is installed on your system. If there is an executable called java installed on your system (and you have JDK 1.8 set as default), they will determine the path automatically. Otherwise, you need to set the JAVA_HOME environment variable to the JDK's home directory:

$ export JAVA_HOME=/path/to/jdk/1.8

For start, you will need to install the KeyStorage JavaCard applet on your card. To do this, run ./install_applet.sh [ARGS...] where ARGS is a list of extra command-line arguments to pass to the GlobalPlatformPro tool (for example -r <reader_name> to select the card reader, or --emv to work with a card that supports EMV). The script will ask you to specify a master password, which will be required to access the keys stored on the card. Note that the installation may sometimes fail with a SCARD_E_NOT_TRANSACTED error -- in such case just retry the installation again.

$ ./install_applet.sh -r 'ACS ACR1281 1S Dual Reader 00 00' --emv
Compiling the applet...
Enter the master password: 
Confirm the master password: 
Installing the applet using GlobalPlatformPro...
Removing existing package
CAP loaded
Applet has been installed successfully! (Unless you see an error message from GPPro - it doesn't set the exit code properly...)

If you want to uninstall the applet, you can use ./delete_applet.sh in a similar fashion.

To list the card readers connected to your system, you can use the ./list_readers.sh script:

$ ./list_readers.sh
[*] ACS ACR1281 1S Dual Reader 00 00
[ ] ACS ACR1281 1S Dual Reader 00 01
[*] ACS ACR1281 1S Dual Reader 00 02

After installing the applet, you should retrieve the card's public key and store it somewhere safe (so that noone can modify it without you knowing):

$ ./get_public_key.sh public.key 'ACS ACR1281 1S Dual Reader 00 00'
Public key has been loaded successfully!

If you want to change the card's master password, use the ./change_password.sh script:

$ ./change_password.sh public.key 'ACS ACR1281 1S Dual Reader 00 00'
Enter master password: 
Enter new master password: 
Verify new master password: 
Master password has been changed successfully!

To create (format) a new LUKS encrypted partition and store it's encryption key on the card, run the ./luks_format.sh script. The first two arguments are the same as for the previous two commands, the third one is the block device/file to be formatted and the fourth one is the size of the key (in bytes; possible values depend on Cryptsetup configuration). You will be asked to enter the master password twice (this is an implementation limitation, don't ask why ;). You will also be asked to provide a recovery passphrase -- this can be used to access the encrypted data in case you lose the card or it gets broken (using Cryptsetup directly). It should be a very strong passphrase -- best is a long random string that you write down on a piece of paper and put in a safe (after all, you should only need it in an emergency).

$ ./luks_format.sh public.key 'ACS ACR1281 1S Dual Reader 00 00' /dev/loop0 32
Generating the key and formatting the partition...
Enter master password: 
Saving the key on the card...
Enter master password: 
Please enter an emergency recovery passphrase in case of card loss...
Enter new passphrase for key slot: 
Verify passphrase: 
Successfully formatted device 'device'!

To "unlock/open" a partition created by ./luks_format.sh, use the ./luks_open.sh script (you will probably need root permissions). You have to specify the name of the mapped device to be created (it will be accessible as /dev/mappper/<name>). This device will allow you to access the encrypted data (see Cryptsetup's documentation for more information).

# ./luks_open.sh public.key 'ACS ACR1281 1S Dual Reader 00 00' /dev/loop0 test
Unlocking partition 30059b10-ee62-4d76-9673-0efeff357773...
Enter master password: 
Successfully opened device '/dev/loop0' as 'test'! 

To close the opened partition, just use the Cryptsetup's close command:

# cryptsetup close test

To delete a partition's key from the card, you can run ./luks_del_key.sh. The partition will be left intact (it can still be accessed using the recovery passphrase).

$ ./luks_del_key.sh public.key 'ACS ACR1281 1S Dual Reader 00 00' /dev/loop0
Deleting key of partition 30059b10-ee62-4d76-9673-0efeff357773...
Enter master password: 
Successfully deleted key for device 'device'!

If you want to also erase the recovery passphrase data from the partition header, use ./luks_erase.sh instead. WARNING: The encrypted data will no longer be recoverable after this operation!

$ ./luks_erase.sh public.key 'ACS ACR1281 1S Dual Reader 00 00' /dev/loop0
Deleting key of partition 30059b10-ee62-4d76-9673-0efeff357773...
Enter master password:
Erasing the partition header...
Successfully erased keys for device '/dev/loop0'!

The applet requires the card to support the following algorithms:

javacard.security.KeyBuilder

• TYPE_EC_FP_* with LENGTH_EC_FP_192
• TYPE_RSA_* with LENGTH_RSA_1024
• TYPE_AES_TRANSIENT_DESELECT with LENGTH_AES_256

javacard.security.KeyPair (key pair generation)

• ALG_RSA_CRT with LENGTH_RSA_1024
• ALG_EC_FP with LENGTH_EC_FP_192 (with preset curve parameters)

javacard.security.Signature

• ALG_RSA_SHA_PKCS1

javacard.security.MessageDigest

• ALG_SHA_256

javacard.security.RandomData

• ALG_SECURE_RANDOM

javacardx.crypto.Cipher

• ALG_AES_BLOCK_128_CBC_NOPAD

The card must also support ISO7816-4 defined extended length APDU messages.

An example of a card that supports all these features is SmartCafe Expert 6.0 80K Dual.