urbit/pkg/arvo/lib/bip39.hoon
2020-12-02 01:00:09 -08:00

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:: bip39 implementation in hoon
::
/+ bip39-english
::
|%
++ from-entropy
|= byts
^- tape
=. wid (mul wid 8)
~| [%unsupported-entropy-bit-length wid]
?> &((gte wid 128) (lte wid 256))
::
=+ cs=(div wid 32)
=/ check=@
%+ rsh [0 (sub 256 cs)]
(sha-256l:sha (div wid 8) dat)
=/ bits=byts
:- (add wid cs)
%+ can 0
:~ cs^check
wid^dat
==
::
=/ pieces
|- ^- (list @)
:- (end [0 11] dat.bits)
?: (lte wid.bits 11) ~
$(bits [(sub wid.bits 11) (rsh [0 11] dat.bits)])
::
=/ words=(list tape)
%+ turn pieces
|= ind=@ud
(snag ind `(list tape)`bip39-english)
::
%+ roll (flop words)
|= [nex=tape all=tape]
?~ all nex
:(weld all " " nex)
::
::NOTE always produces a 512-bit result
++ to-seed
|= [mnem=tape pass=tape]
^- @
%- hmac-sha512t:pbkdf:crypto
[(crip mnem) (crip (weld "mnemonic" pass)) 2.048 64]
--