Codex32

This library is Codex32 ruby implementation.

Installation

Add this line to your application's Gemfile:

gem'codex32'

And then execute:

$ bundle install

Or install it yourself as:

$ gem install codex32

Usage

require'codex32'# Parse codex32 share.share=Codex32.parse("ms10testsxxxxxxxxxxxxxxxxxxxxxxxxxx4nzvca9cmczlw")# Get share data.share.data# Split a master seed into 5 shares, any 3 of which recover the seed.# The shares are derived from random values obtained from SecureRandom.shares=Codex32.split(seed: "ffeeddccbbaa99887766554433221100",id: "test",threshold: 3,share_indexes: %w[acdef])shares.map(&:to_s)# Recovery master seed using shares.share1=Codex32.parse("MS12NAMEA320ZYXWVUTSRQPNMLKJHGFEDCAXRPP870HKKQRM")share2=Codex32.parse("MS12NAMECACDEFGHJKLMNPQRSTUVWXYZ023FTR2GDZMPY6PN")secret=Codex32.generate_share([share1,share2],Codex32::SECRET_INDEX)# Obtain master seed.secret.data# Generate new share with index 'd'share3=Codex32.generate_share([share1,share2],"d")# Obtain bech32 string.share3.to_s

Security considerations

Codex32 strings and master seeds are secret material. Keep the following limitations in mind.

• Use Codex32.split to create shares. Shares built from anything but cryptographically secure randomness leak the master seed. Codex32.split uses SecureRandom.
• Verify a backup before relying on it. Recover the master seed from a threshold of the shares and compare it with the original. Codex32.split performs this check once for the shares it returns.
• This library is not constant time. Character lookups, the field arithmetic and the validation errors all depend on the data being processed. Run it on a machine you trust, preferably offline, and do not feed it input from untrusted parties on a shared host.
• Secrets are not erased from memory. Ruby gives a library no reliable way to wipe a string, so master seeds and shares stay in the heap until they are garbage collected, and may be copied by the GC or swapped to disk.