News | Project Presentation | Architecture | Data Structures | Security | References | Project Page

SecCube Security

Protection modes

• its metadata (i.e INIT and MAP records) are always MACed. This guarantees the authenticity of those records. For instance, it prevents an attacker from modifying SecCube's configuration (in the INIT record).
• end-user records (aka 'payload') are optionally secured. They may be hashed, MACed (= a kind of signature), timestamped and / or encrypted. In all cases, the protection mode applies to the entire record, i.e the payload, its length and its label (see datarecordheader_t structure). If timestamping is set, the record is timestamped at the time it is put in the SecCube.

Note SecCubes protect records (INIT, MAP or DATA), but not individual blocks. The reasons are twofold: 1/ we are interested by confidentiality / authenticity of end-user's payload (i.e. the DATA record) not in a finer granularity, and 2/ protecting each blocks would reserve more physical space in the SecCube.

End-user record protection modes may be combined (e.g. timestamped and signed). On a security point of view, combining hashes and MACs boil down to the same as only MACs because MACs provide integrity + authenticity, whereas hashes provide only integrity. However, we do not restrict such combinations.

Several protectiion mode combinations are possible. They are always processed in the same order:

1. timestamp the record, append the time stamp to the record.
2. hash the record (including timestamp), append it.
3. MAC the record (including timestamp and hash), append it
4. encrypt the record (including timestamp, hash and MAC)

SecCube keys

• a record encryption key. This key is used to encrypt DATA records. It is optional (depends on protection mode selection). It is stored in the INIT record, encrypted by a public key.
• a MAC key. This key is stored in the INIT record, encrypted by a public key. It is used to MAC SecCube's INIT and MAP records. Additionally, if the SecCube is configured for DATA record authenticity, this key MACs DATA records.
• a public key. This public key is used to wrap the record encryption key or the MAC key. It is stored in the INIT record, in OpenPGP's armoured public key format.
• a private key. This key is used to unwrap record encryption key and MAC key. It is never stored in the SecCube, and must be provided by the caller.