A utility package for splitting a BIP39 seed mnemonic into shares that can later be combined to recover the seed.

Use this method to securely distribute your BIP39 mnemonic among your trusted ones to protect from theft and to allow recovery during a disaster.

Each share is completely meaningless on it's own and a single person holding a share cannot steal your funds. The original BIP39 mnemonic can only be recovered by combining the shares together.

A threshold can be provided to allow a minimum number of the total shares to be collected in order to recover the mnemonic. For example: Given a seed mnemonic split into 4 with a threshold of 3, one of the shares can be lost or stolen, and still the mnemonic can be recovered using the 3 available ones.

shareable-seed encodes mnemonic seeds into a special format called a shareable_code (described below) and then splits it into shares using Shamir's threshold secret sharing scheme.

shares can later be combined together back into the shareable_code and decoded into the original seed mnemonic.

<versionCode(8bitHex)><wordlistCode(8bitHex)><entropyLenghHex(8bitHex)><entropy(zeroPadded256bitHex)><checksum(32bitHex)>

npm install shareable-seed --save

const mnemonic = 'seed sock milk update focus rotate barely fade car face mechanic mercy'

// Split english mnemonic into 3 shares with 2 of them necessary for recovery
const shares = shareableSeed.mnemonicToShares(mnemonic, 3, 2, 'v1', 'english')
/* =>
{ '1': '801a17b2d8d79510c8238731868ca9a9df962b8f2388d787c5a1ca7bfc41e89b5cb1c6ba473b95c81d40900007f5adcf48b',
  '2': '8025ff65a07f2a2181973e530b0892927efc46df97007f0f8b43853639567192cdda119ad6ea34390d3cc5678acdc6e79f1',
  '3': '803fe8d778a8bf3149b4a9728f843b3ba16a6d50b488a8884ee24f4dc51bb695b24ca37aa655ebd9f258f6450165500022c' }
*/

const shareList = _.values(shares).slice(0, 2)

const recoveredMnemonic = shareableSeed.shareListToMnemonic(shareList)

console.log(recoveredMnemonic === mnemonic)
// => true