Practical Cryptography

I recently learned about a really cool program called magic wormhole.

It lets you securely send files from one computer to another, aka the XKCD problem.

This is all you do. Sender runs wormhole send <filename> in a terminal. It gives you a code like 7-crossover-clockwork.

The receiver runs wormhole receive and enters the code. That’s it.

Here’s a Pycon talk from the author about it:

You know what’s cool and easy that almost nobody knows about or uses?

You don’t even need Firefox to use it.


Lol I use both of these regularly.

I was also real ready to see a thread about bitcoin and get all snarky. I’m almost sad I don’t get to now.

Didn’t know signal got $50 million from the whatsapp guy:

Also: use Signal.

TIL about the NIST beacon:

Damn. Get better soon, Send.

Oh no. We use this for GeekNights.

You could magic wormhole for the time being.

That’s not a very easy way to send a file between two windows PCs.

No? You don’t have wsl installed on both ends? Or you mean two arbitrary PCs.

Rym doesn’t have it.

Also, that’s way way more effort than dragging a file onto a web page, then copy/pasting a download link.

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I use this regularly. It’s an amazing tool and I’m really hoping it’s not down for very long.

This is an interesting thought experiment. If I had to send someone a big file, how would I do it?

  1. Encrypt file if I’m putting it on the internet, assuming recipient is savvy.
  2. Poke a NAT hole and do one of:
    1. Set up a quick HTTP server
    2. Set up selt-hosted bittorrent?
    3. Set up a restricted sftp login?

There’s also the classic “mail media” option.

Mega is still an option but caps itself at 50 GB for a Free account.

Another one enters the chat.

There’s lots of sites like this

I obviously can’t understand shit this paper is talking about. But it seems like they have a way to quickly and easily factor prime numbers, which if true, I believe would substantiate the claim they make of destroying the RSA cryptosystem. That “if true” is at the bottom of the dead sea as far as I’m concerned. Let’s wait and see what people who understand math say, and if anyone can produce an actual functioning program.

It’s at least mildly interesting that someone would have the guts to publish and make the claim.

Matthew Green is a cryptography professor:

I’m not a cryptography professor, but “This destroyes the RSA cryptosystem” as the closing line of the abstract seems like a very strange choice.

I agree. I’m curious as to why that line is on the web site. It is not in the PDF.

Also TIL I can get $200k if I can factor this number number.

My favourite cryptographer has taken a quick glance:

I have been seeing this paper by cryptographer Peter Schnorr making the rounds: “Fast Factoring Integers by SVP Algorithms.” It describes a new factoring method, and its abstract ends with the provocative sentence: “This destroys the RSA cryptosystem.”

It does not. At best, it’s an improvement in factoring — and I’m not sure it’s even that. The paper is a preprint: it hasn’t been peer reviewed. Be careful taking its claims at face value.