crypto, rpc: poc mnemonics

[div72]

Other Seed Phrase Schemes

BIP39

• Variable phrase length (12-24 words, 128-256bit entropy)
• 4-8 bit checksum (breaks wordlist independence)
• Unversioned
• Existing HD master keys cannot be used, new wallet must be generated

Electrum

• Variable phrase length (12 words, 135bit entropy by default)
• Versioned(derived from the first 4 + 4n bits of HMACSHA512(seed phrase)), also used as a checksum (8 + 4n bits)
• Wordlist independent
• Existing HD master keys cannot be used, new wallet must be generated

aezeed

• Constant phrase length (24 words, 128bit entropy)
• Double-versioned, 8bit for the external version (determines how to decode) & 8 bits for the internal version (determines how to derive the keys)
• 64bit checksum
• 40bit salt for the password
• 16bit wallet birthday (in days) for faster seed imports
• Requires a niche scheme called aez
• Existing HD master keys cannot be used, new wallet must be generated

This currently

• Constant phrase length (32 words, 128bit entropy)
• Double-versioned, 8bit for the external version (determines how to decode) & 8 bits for the internal version (determines how to derive the keys)
• 128bit checksum
• 64bit salt for the password
• 16bit wallet birthday (in days) for faster seed imports
• Existing HD master keys cannot be used, new wallet must be generated

[jamescowens]

I like this. What are your thoughts on the +/- of this versus a BIP39 implementation? I don't think it matters, because the keys are not portable across chains anyway...

[div72]

@jamescowens A bit late, but I updated the PR description with data from BIP39, Electrum's seed system and aezeed(lightning's seed system).

I like the properties of aezeed, but a major downside of it is that it uses aez which is a pretty niche scheme. I basically replaced it with ChaCha20Poly1305 but that's more heavy storage-wise.