I would like to audit how an implementation of an encryption algorithm is really performed with the following given data of the problem:
- the encryption mechanism is reversible (this isn’t a signature),
- the algorithm is pretended to be AES, but might be implemented correctly or not, or worse something else,
- the key is not known (in the case I am interested in, I want to check that all files are really and correctly encrypted, but I could play with specifically designed ones),
- I don't have access to the source code.
At least I would like to be able to detect that the file is not encrypted. Next I would like to be able to detect that the RNG is running in a tiny set or not really random.
In a first approach I thought to make an analysis of the randomness quality of the encrypted file: average value + standard deviation (with a tool like
But I immediatly thought of artificial files with a perfect average value
and standard deviation which are perfectly regular and not the result of any encryption.
Then my first approach is wrong.
The environment in which I will make this audit is a Unix one. ( I cannot use tools or algorithms I cannot read, compile and check myself. )
I would like to check that my iPhone is correctly encrypted and what is the AES key derived from either a constant, my password, a hardware uniq identifier.
I would like to perform the same validation of an iPhone of any staff member which will ask me to make the same validation for his professionnal iPhone. This is a service toward users to provide them trust in what they think is encrypted and has to be.