undefined | Better HN

Skip to content

Top Best Ask Show New Jobs

0 pointspxx2y ago0 comments

Encryption in the 70s resists today's attacks just fine. DES was weakened on purpose (short key length, but the idea for 3DES dates from 1978). In the asymmetric realm you still can't break a full length RSA key.

Maybe it's not fully contemporaneous with Voyager but the claim that 70s encryption is insufficient doesn't stand up to scrutiny

0 comments

5 comments · 2 top-level

Dylan168072y ago· 2 in thread

What was "full length" at the time, even if they got RSA implemented immediately after the paper was announced?

The RSA paper recommends 200 digit keys, which is somewhat under 700 bits. Would even that size run acceptably on an 8 kiloword 0.1MIPS machine? (I couldn't quickly find an actual opcode listing, so I can't say exactly how fast it multiplies, but it's probably not great.)

eru2y ago

Why would you use public key encryption here in the first place? Just use a symmetric cipher.

Dylan168072y ago

What's a symmetric cipher from the 70s that we can't brute force today?

(And I'm not counting "the idea" of 3DES when even that was after voyager already launched and it wasn't properly set up until 1981. Also 3DES has enough weaknesses that I wouldn't trust it to be uncrackable today.)

amenhotep2y ago· 1 in thread

It's not the full length RSA key that's the worry, though, it's the structure around it that Bleichenbacher finds clever ways of poking holes in.

I don't think Voyager would be very vulnerable to an adaptive chosen ciphertext attack regardless. But you don't need the 70s maths to be wrong, you only need the engineering to have a flaw.

wolverine8762y ago

Is today's engineering different? One could argue that we have 50 years more of experience with the engineering (though the components have changed too, requiring newish engineering), and I would guess that we invest more resources in such things these days.

j / k navigate · click thread line to collapse