Multi Factor Encryption? I got an alert last night to the keywords above and was curious, so took a look at the tor site flagged which is the following one:
http://nsrz5iogimqwgeax3clpp6hvfy6viom2woy7dghgxes4sqk63r7svoqd.onion. Obviously you need TOR to access it or a service like Tor2Web though reachability is spotty.
I'm asking SE because these guys are claiming to offer a cipher strength I've never heard of. I'd like to ask if you think it's even possible.
This question is about the encryption scheme &quot;Blobby&quot; presented on their site and the security claims surrounding it.
The first notation they use is $10^{yM}$ which I didn't get, but just below is an example $10^{41485806}$, which seems obscene with the unit to of the previous number being &quot;operations&quot;, which can be inferred from them stating a relative strength of $10^{38}$ for AES-128 which is roughly $2^{128}$.
Now that I've have longer to look at it, it feels less impossible (though still a stretch), I think the key size and password length are important, but I suspect they're using a third mutagen.
The key claim of novelty for this encryption scheme is that both a nearly-arbitrary sized password (20-$2^{12}$ chars) and an arbitrary sized key ($2^{16}$-$\infty$ bit) are necessary for symmetric operation yielding &quot;multi-factor security&quot; with their custom encryption scheme. The precise quote is

Blobby is fundamentally different, the password is used in conjunction with the key, meaning that each is useless without the other, and attacking the key's password won't get you any closer to the message password.

If their claim is solid, would this be quantum resistant?
I have now downloaded the 3 sample files and looked at them, they are clearly encrypted. I've been trying the first sample for over 24hours now with not a whisper of joy.
Oh boy. Snakeoil at its finest.

This question is about the encryption scheme &quot;Blobby&quot; presented on their site and the security claims surrounding it.

Inventing and selling completely new symmetric encryption? One of the best indicators for snakeoil.

The first notation they use is $10^{yM}$ which I didn't get, but just below is an example $10^{41485806}$, which seems obscene with the unit to of the previous number being &quot;operations&quot;, which can be inferred from them stating a relative strength of $10^{38}$ for AES-128 which is roughly $2^{128}$.

It seems they use big numbers for the sake of using big numbers and impressing people. For all practical purposes nothing beyond 256-bit security matters unless you want to invest the entire energy of the sun for most of its lifespan into breaking it. Double that number if you want to go &quot;sure&quot; against quantum computers thanks to Grovers provenly optimal search algorithm.

If their claim is solid, would this be quantum resistant?

It could be that their scheme is quantum-resistant. Symmetric crypto is rather easy to get quantum-resistant. But we don't know until they actually publish a description and even then we might not know because people won't care enough to analyze this scheme.

I'd like to ask if you think it's even possible.

Yes, you can build multi-factor encryption and you can build it nicely out of standard cryptographic primitives.
Now for the actual question you are probably having: &quot;Ok, this is all snakeoil they're trying to sell me and you're saying that we don't need this, so how would you do it in practice?&quot;
Well turns out people already did look at this problem, i.e. how to combine something that you know (like a password) with something that you have (i.e. a pre-generated key, a key-file or a security token).
My favourite three examples for this are the softwares VeraCrypt, BestCrypt and KeePass, which all handle this in a different way.

VeraCrypt will essentially mix your keyfile(s) with your password using their funky custom hash function and then run this through standard password-based key derivation. A random salt from the ciphertext will still be used.
BestCrypt will hash each of your keyfiles individually and then sort the hashes and prepend the hashes to the salt before key derivation.
KeePass will hash your keyfile and concatenate it with your password before feeding that into the password-based key derivation. A random salt from the ciphertext will still be used.

Obviously you need both inputs in all three cases to mount a brute-force / dictionary attack. Also note that any attack that would allow you to recover the password-based key derivation input without actually doing the forward iteration would be considered a major publication-worthy break. And yes there are publications that show that for standard password-based encryptions the optimal strategy is to search the password space or guess a secret symmetric key, the best one of which is probably by Bellare, Ristenpart and Tessaro (Theorem 3.4).