cryptosystem

The fact that they have effectively invented their own mode is suspect, and the cryptosystem as a whole is not really well-validated either.

At worst, they've implemented a cryptosystem that, having never been peer reviewed, is vulnerable to basic attacks.

Yet another reminder that it's no challenge to create a cryptosystem that the inventor themselves cannot break.

You generally don't want to trust the confidentiality of a cryptosystem that doesn't check ciphertext integrity and rule out manipulated ciphertexts.

If a distance measure can be found for a cryptosystem, it's thus easily breakable.

Not something to build an entire cryptosystem around, but still a fairly safe assumption.

It's not perfect, but it's a sound design of a very conventional cryptosystem.

So to me a 'cryptosystem' is the way the elements are combined.

The cryptosystem behind it is called The Update Framework[0], and provides a lot more flexibility and protection than PGP (on top of using modern crypto).

Probably not very practical if you're not building a cryptosystem, but it's a nice way to get a lay understanding---and scare you enough about how many pitfalls there are.

Block ciphers are used in a selection of modes and when combined into a protocol with integrity and authentication catered for, we have a cryptosystem.

We invented this novel cryptosystem and, despite it being unproven and not having it validated by anyone, we reckon it's the most secure thing ever!

I really like this principle from cryptography: "Anyone can make a cryptosystem that he himself cannot break."

I'm not sure whether I'm an "expert", but I can't think of a competently designed cryptosystem falls to that particular attack.