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Create PGP key from a passphrase
131 sats \ 3 comments \ @ln123 26 Aug 2022 bitcoin
Here's the tool: https://github.com/skeeto/passphrase2pgp
Why do this?
Much easier than typing it from a piece of paper! And means you can send that secure email / open your self-hosted password manager directly on any machine.
But wait - can't it be brute-forced?
Actually no, not easily - there's "proof of work" involved. Quote from the website:
Isn't generating a key from a passphrase foolish? If you can reproduce your key from a passphrase, so can any one else!
In 2019, the fastest available implementation of Argon2id running on the best available cloud hardware takes just over 6 seconds with passphrase2pgp's default parameters. That's 6 seconds of a dedicated single CPU core and 1GB of RAM for a single guess. This means that at the current cloud computing rates it costs around US$50 to make 2^20 (~1 million) passphrase guesses.
A randomly-generated password of length 8 composed of the 95 printable ASCII characters has ~52.6 bits of entropy. Therefore it would cost around US$ 158 billion to for just a 50% chance of cracking that passphrase. If your passphrase is generated by a random process, and it's at least this long, it is not the weak point in this system.
Does anyone have thoughts on this?
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101 sats \ 2 replies \ @sandbeach123old 26 Aug 2022
Very interesting. However in my case the private key for email I actually prefer to change it every year, instead of the master key (and seed) for btc, which I would prefer to keep unchanged for many years. I do not trust myself to safely enter/generate/handle any seed on anything other than a Hardware wallet or a piece of paper/metal. IMHO.
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20 sats \ 1 reply \ @ln123 OP 26 Aug 2022
makes sense. I thought I ready somewhere that you can generate new keys from a master PGP key.
If only it were possible to generate a PGP key from a hardware device (such as ledger), using the seed, with a pin code for salt!
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1 sat \ 0 replies \ @sandbeach123old 26 Aug 2022
Yes, that would be nice. My HW generate a GPG privkey and then I just enter that to generate a GPG pubkey in my PC. Then after x time I just generate another GPG privkey from my HW and so on. The only issue I would worry is the possibility of an attacker to get a few of those privkeys and deduct or infere other possible privkeys, like with the HD keys derivation scheme.
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