Update
You can now encrypt plain text, so anything you want. With this, you can send sensitive information over insecure channels or share publicly with real plausible deniability. (below 2000 characters works without issue)
Changes
I rebuilt the system with a different encryption design, and address many of the flaws pointed out in V1.
I really wanted any password to always decrypt so you never know if you are right. I found the XOR algorithm that does this, but there is an entropy problem, where an incorrect password will almost always output non-common characters, I attempted to solve this at its core by diving into the math and some research papers but got nowhere, as it seemed to be almost impossible.
I tried finding an algorithm that would give me perfect plausible deniability, so if you shared a link X with a password you could use a different password and get Y, saying you never intended to share X. It doesn’t exist 😢 I came up with a workaround by adding decoys which are mutable XOR ciphers joined, it allows you to set what other data is included, so you can tailor your alibi.
Here is the demo link. There are three memes you can find
Password: test1, test2, test3
Safety
It should be safe to share data encrypted with this method, I did some basic brute force tests and did not find any shortcuts, I have a rough estimate of a billion years on a server farm for a 12digit password.
Considerations
@[email protected] said:
“There’s 2 secrets here: the link and the password. And to share it with someone you need to share 2 secrets: the locked link and the password.”
A strong password is almost impossible to crack, but you can use a popular text link tool like pastebin with expiry to mask the encrypted data. As for eliminating the password, I have considered using the site as the ‘shared secret’ so you share just the cipher, and if you know the URL you can paste it in, and it would be encrypted/decrypted with a derived key the site stored.
Hey, thanks for the thoughtful breakdown. I probably should label it: warning random IT grad project. I mistakenly believed I could make something that was good, well it’s a lot more difficult. You’re right that this doesn’t provide the kind of plausible deniability I initially hoped for, the decoys were just a workaround, because I couldn’t find the type of algorithm I wanted.
The query parameters are masked with HTTPS so you’re not revealing any extra data, it would just look like any other redirect if you were packet sniffing. And when visiting the destination links, your normal OPSEC still applies, like changing your DNS, using a VPN, etc. I was just seeing if this project would find some sort of use, but I only spend two days on it and it was a fun learning experience.
I would encourage rolling your own crypto for fun, because, well, it is. But yeah, you should maybe also make clear that people should not use it, because that is rule 1 of cryptography.