# SmartPGP applet SmartPGP is a free and open source implementation of the [OpenPGP card 3.x specification](http://www.g10code.com/docs/openpgp-card-3.0.pdf) in JavaCard. The main improvement introduced in OpenPGP card 3.x specification from previous version is the support of elliptic curve cryptography with several existing curves (NIST P-256, NIST P-384, NIST P-521, brainpool p256r1, brainpool p384r1 and brainpool p512r1). ## Features The following features are implemented at the applet level, but some of them depend on underlying hardware support and available (non-)volatile memory resources: - RSA (>= 2048 bits modulus, 17 bits exponent) and ECC (NIST P-256, NIST P-384, NIST P-521, brainpool p256r1, brainpool p384r1 and brainpool p512r1) for signature, encryption and authentication; - On-board key generation and external private key import; - PIN codes (user, admin and resetting code) up to 127 characters; - Certificate up to 1 kB (DER encoded) for each key; - Login, URL, and private DOs up to 256 bytes; - Command and response chaining; - AES 128/256 bits deciphering primitive; - Secure messaging (see below). ## Default values The SmartPGP applet is configured with the following default values: - Admin PIN is 12345678; - User PIN is 123456; - No PUK (a.k.a. resetting code) is defined; - RSA 2048 bits for PGP keys; - NIST P-256 for the secure messaging key. These values can be changed by modifying default values in the code (see the [Constants](src/fr/anssi/smartpgp/Constants.java) class). When the applet is installed, one can use the `smartpgp-cli` utility given in the `bin` directory to change these values. Keep in mind that when you change the algorithm attributes of a PGP key or of the secure messaging key, the key and the corresponding certificate are erased. Also note that hard coded default values will be restored upon a factory reset. ## Compliance with OpenPGP card 3.x specification The SmartPGP applet implements the complete OpenPGP card 3.x specification, except the secure messaging related features: - Commands and responses protection is not implemented as described in the specification. Motivation and implementation details are explained in the [secure messaging document](secure_messaging/smartpgp_sm.pdf); - A command protected by secure messaging is not granted admin rights. Secure messaging can thus be used to protect communications only, especially when the token is used contactless; - If and only if secure messaging static key and certificate have been provisioned, all commands containing sensitive data (e.g. PIN code, decrypted data, private key, ...) emitted through a contactless interface must be protected by secure messaging or they will be refused; - The `ACTIVATE FILE` with P1 = P2 = 0, as described in the specification, resets everything except the secure messaging static key and certificate. Complete reset, including these elements, can be performed with `ACTIVATE FILE` with P1 = 0 and P2 = 1. # Application support Tokens following the OpenPGP card 3.x specification are not yet fully supported by most PGP applications. ## GnuPG OpenPGP card 3.x is supported by [GnuPG](https://www.gnupg.org/) starting from version 2.1.16. The specific secure messaging of the SmartPGP applet is **not** supported at all at is not part of the OpenPGP card 3.x specification. ## OpenKeychain OpenPGP card 3.x is supported by [OpenKeychain](https://www.openkeychain.org/) starting from version 4.2 (not yet released, see [git master branch](https://github.com/open-keychain/open-keychain) project). Only NIST curves are supported. The secure messaging of the SmartPGP applet is fully supported in OpenKeychain. See the section below for more information on the setup process. # Content of the repository The repository contains several directories: - `bin` contains a Python library and command line tool called `smartpgp-cli` to interact with an OpenPGP card 3.x but also to deal with the specific secure messaging feature of the SmartPGP applet; - `secure_messaging` contains documentation and example scripts to play with the secure messaging feature of SmartPGP; - `src` contains the JavaCard source code of the SmartPGP applet; - `videos` contains sample videos demonstrating smartcard interactions with OpenKeychain and K9 mail on Android Nexus 5. # Build and installation instructions ## Prerequisites - JavaCard Development Kit 3.0.4 (or above) from [Oracle website](http://www.oracle.com/technetwork/java/embedded/javacard/downloads/index.html); - The `ant` tool 1.9.4 (or above) from your Linux distribution or from [Apache Ant project website](http://ant.apache.org/); - A device compliant with JavaCard 3.0.4 (or above) with enough available resources to hold the code (approximately 23 kB of non-volatile memory), persistent data (approximately 10 kB of non-volatile memory) and volatile data (approximately 2 kB of RAM). ## Reducing flash and/or RAM consumption The applet allocates all its data structures to their maximal size at installation to avoid as much as possible runtime errors caused by memory allocation failure. If your device does not have enough flash and/or RAM available, or if you plan not to use some features (e.g. stored certificates), you can adjust the applet to reduce its resource consumption by tweaking the following variables: - `Constants.INTERNAL_BUFFER_MAX_LENGTH`: the size in bytes of the internal RAM buffer used for input/output chaining. Chaining is especially used in case of long commands and responses such as those involved in private key import and certificate import/export. - `Constants.EXTENDED_CAPABILITIES`, bytes 5 and 6: the maximal size in bytes of a certificate associated to a key. Following the OpenPGP card specification, a certificate can be stored for each of the three keys. In SmartPGP, a fourth certificate is stored for secure messaging. ## Building the CAP file - Copy the `javacard.properties.example` file to a file named `javacard.properties`; - Edit the `javacard.properties` file and set the path of your JavaCard Development Kit; - (Optional) Edit the `build.xml` file and replace the `0xAF:0xAF` bytes in the `APPLET_AID` with your own manufacturer identifier (see section 4.2.1 of OpenPGP card specification); - Execute `ant` with no parameter will produce the CAP file in `build/fr/anssi/smartpgp/javacard/smartpgp.cap`. ## Building the CAP file with Gradle - Set path to the JavaCard Development Kit: `export JC_HOME="your/path/to/javacardkit"` - Execute `gradle convertJavacard`. It will produce the CAP file in `build/fr/anssi/smartpgp/javacard/smartpgp.cap`. ## Installing the CAP file The CAP file installation depends on your device, so you have to refer to the instructions given by your device manufacturer. Be careful to use a valid AID according to the OpenPGP card specification (see section 4.2.1) for each card. # Setting up secure messaging with OpenKeychain The patch written for OpenKeychain permits to use the secure messaging feature with or without token authentication. ## Secure messaging without token authentication Without token authentication, you are not protected against man-in-the middle attack as your device cannot ensure it is communicating directly with a trusted token. Nevertheless, the communications with the token are still protected in confidentiality against passive attacks (i.e. traffic capture). If you want to test secure messaging without token authentication, you can use the following command to order the token to generate its secure messaging key on-board. `./smartpgp-cli -r X -I generate-sm-key -o pubkey.raw` In this case, you have to deactivate the certificate verification in OpenKeychain: go to "Parameters" > "Experimental features" and deactivate the option called "SmartPGP verify certificate". ## Secure messaging with token authentication The `secure_messaging` directory contains a subdirectory called `pki` which contains two sample scripts to generate a certificate authority and token certificates. The sample scripts are given **only** for test purposes of the secure messaging feature with certificate verification. They require `openssl` to be installed on your system. If you want to use your own PKI, you have to generate a specific intermediate certificate authority to sign the certificates of your token(s). Then, you have to provision the complete certificate chain from this new intermediate CA to your root CA in OpenKeychain because the certificate verification implemented in the given patch does not rely on the system keystore. ### Generate a sample CA key and certificate Change your current directory to the `pki` directory and execute the script `./generate_ca.sh`. It will produce a sample CA key in `PKI/private/ca.key.pem` and the corresponding certificate in `PKI/certs/ca.cert.pem`. ### Generate a sample token key and certificate Change your current directory to the `pki` directory and execute the script `./generate_token.sh mycard1` where `mycard1` is some unique identifier for the token. It will produce a sample token key in `PKI/private/mycard1.key.pem` and the corresponding certificate in `PKI/certs/mycard1.cert.pem`. ### Provision the token with its sample key and certificate Change your current directory to the `bin` directory and execute the following commands after replacing the reader number `X` by the number of the reader that contains your token, and the path to the `pki` directory used in previous sections. The following command imports the token key in the token. `./smartpgp-cli -r X -I -i path_to_the_pki_dir/PKI/private/mycard1.key.der put-sm-key` The following command imports the token certificate in the token. `./smartpgp-cli -r X -I -i path_to_the_pki_dir/PKI/certs/mycard1.cert.der put-sm-certificate` These commands have to be executed in this order because the key import clears any previously stored certificate. Once the token key is imported, you should remove the token private key from you system as there is no need to keep it outside of your token. ### Install the CA in OpenKeychain - Upload the CA certificate `PKI/certs/ca.cert.pem` to your phone; - Go to "Parameters" > "Experimental features" and activate the option called "SmartPGP verify certificate`; - Click on "SmartPGP trusted authorities", and then on "+" at the top left; - Set a name for this authority and select the file you uploaded.