How to sign data in MySQL database revision safe (trusted timestamping)?

Question

I am currently planning a project in which revision safety of the database data is important. This means: we want to be able to proof that the data in the database was not tempered with since it was imported - no user changed the value, no db admin logged into the database and changed it.

What is the best way to achieve this?

Till now, I like the idea of signing the database row best: I create a MD5 hash of all the fields in the row, then send it to a timestamping signing server (have a look on wikipedia) and store the created signature with the row. From this time on, we can prove that no one changed the row since this stamp was created.

Any better ideas? And, if you like the idea as much as I do, what timestamp server should I use and how can I access it? The Verisign Timestamp Server seems to be used a lot, but I could not find any documentation on how to use it "raw", e.g. without the Microsoft code signer tools etc.

Thank you!

Answer 1

Time stamp servers are usually not free-to-use.

Alternatively you may use an HMAC-MD5 (or HMAC-SHA1) instead and use a password that is only known to the authorized user. The password is of course not directly used, better via PKCS#5 or at least hashed with a seed. Without the password noone can verify or recreate the HMAC-MD5