2 ms·

Yeah, "cryptographically secure" and "something you remember" doesn't mix well. 128 bits (say) is a lot of data to memorize. Having it be a real approximation t

by e12e 8y ago

Yeah, "cryptographically secure" and "something you remember" doesn't mix well. 128 bits (say) is a lot of data to memorize. Having it be a real approximation to random doesn't help. I suppose the pgp/ssh model of secure device holding the master key plus the ability to backup (eg qr code printout in a safe). An approximation for phones would be a random key locked in the device with a pin, an the ability to transfer and backup keys as you mention. Other than that - I've not really heard of gpg keys or ssh keys being brute forced - but that may be because by the point you gain access to the (encrypted) private key - you already have access to everything else? [ed: for example there are 52 cards in a normal deck of cards, meaning each card encodes about 5.7 bits(2^5=32,2^6=64). You could represent a ~128 bit key as a sequence of ~23 random cards. Or add add a few checksum bits and use half a deck (26 cards). Note, shuffling a deck isn't a great source of randomness, but you could use dice or a computer to generate the key - then map it to a sequence of cards.]

ben0x539 8y ago
128 bits is like, what, ten words chosen randomly from a suitably large dictionary? Is that really prohibitive? Even as random alphanumeric string that doesn't seem beyond muscle memory. Seems like the biggest pain would be to input it consistently on a phone keyboard.
- e12e 8y ago
  10 random words from a really large dictionary. Narrow down to, say words three to five letters, and 128 bits get tricky. It's easier in the sense that we have a certain active/passive vocabulary - but you'd probably need a mnemonic with words too. [ed: input is definitely a challenge. I've considered making various alternative input methods - but in the end 128 bits is a lot of data to input without error. Especially on a phone. Of course on a phone you might have a pin protected secure enclave for example, or use an external nfc key etc. But it then we're back to some way to remember 128 bits - and maybe even without the luxury of "practice" by way of typing it a few times a day...]
- geofft 8y ago
  Seems hard to reliably remember 10 words chosen randomly unless you use them very regularly. I don't want to type in a ten-word passphrase every time I open my texting app?

by e12e 8y ago

ben0x539 8y ago

128 bits is like, what, ten words chosen randomly from a suitably large dictionary? Is that really prohibitive? Even as random alphanumeric string that doesn't seem beyond muscle memory. Seems like the biggest pain would be to input it consistently on a phone keyboard.

e12e 8y ago
10 random words from a really large dictionary. Narrow down to, say words three to five letters, and 128 bits get tricky. It's easier in the sense that we have a certain active/passive vocabulary - but you'd probably need a mnemonic with words too. [ed: input is definitely a challenge. I've considered making various alternative input methods - but in the end 128 bits is a lot of data to input without error. Especially on a phone. Of course on a phone you might have a pin protected secure enclave for example, or use an external nfc key etc. But it then we're back to some way to remember 128 bits - and maybe even without the luxury of "practice" by way of typing it a few times a day...]
geofft 8y ago
Seems hard to reliably remember 10 words chosen randomly unless you use them very regularly. I don't want to type in a ten-word passphrase every time I open my texting app?