# Value of new symmetric key algorithm

When I was in grad school, I invented (discovered?) a new PRNG algorithm. This algorithm has an infinite period length (given infinite memory). This in itself cannot be new, because all you need to do to accomplish this is simply take digits from an irrational number. What does make this different, is that it is able to use any size of key. 1 bit, 1 GB, whatever.

The next logical step for me was to turn this into a symmetric key algorithm. simply by generating the bits based off of the seed, and XORing the source file bits with the resulting output.

I am in the middle of developing this into an Android app. My problem is that 100% of my experience has been academic. I know that this algorithm (Binary Lagged Fibonacci) is valuable academically, but does it have a practical value? Does the flexible key size alone give it a benefit over, say, AES?

I have sent some emails out to a few companies, and I am trying to find out why no one has responded at all. My best guess is that 1. they get 1000 crackpots emailing them every day. Or 2. I sound like I have no idea what I am talking about. The second one is definitely true. I just learned the other day I need to be salting the seed when it gets passed.

• Variable key-sizes aren't all that useful in practice where you'd use KBKDFs, PBKDFs and hashes to get down to supported and secure-enough sizes. – SEJPM Nov 28 '16 at 20:53
• – CodesInChaos Nov 28 '16 at 21:50
• If you supply for example, a 512-bit key, can you prove that your algorithm provides 512-bits of security against all known attacks? – Richie Frame Nov 29 '16 at 2:13
• Or, for that matter, any security at all? – poncho Nov 29 '16 at 2:43
• "Binary Lagged Fibonacci"; Knuth (volume 2, section 3.2.2) references some lagged fibonacci generators dating back to the 50s. If what you have is a minor variant of what was invented almost 60 years ago, it's not clear if it's of any academic interest (and those wouldn't certainly not be of any cryptographical interest) – poncho Nov 29 '16 at 4:53

Without a proof of security or proper cryptanalysis including an argument why it covers all currently known methods:

The value (in the context of cryptography) is zero.

This might sound harsh, but you brought up the main reason yourself: It is basically impossible to design a new secure cryptosystem without the proper knowledge of the field, but amateurs are convinced otherwise and keep on trying. The only solution here is to write a publication in some peer-reviewed context (e.g. crypto conferences). Regarding your experience, it is not clear from your question, because you wrote:

My problem is that 100% of my experience has been academic

Or 2. I sound like I have no idea what I am talking about. The second one is definitely true