seedsplit

A simple and information-theoretic secure seed phrase splitting scheme.

... And mostly just an exercise for me to practice Rust. Because you probably shouldn't be putting your seedprhase on a CLI you found on github.

Algorithm

The algorith is explained in this stackexchange answer.

Zero indexed

There might be some confusion if the word list is zero or one indexed. As stated in BIP39:

bits of its SHA256 hash. This checksum is appended to the end of the initial entropy. Next, these concatenated bits are split into groups of 11 bits, each encoding a number from 0-2047, serving as an index into a wordlist. Finally, we convert these numbers into words and use the joined words as a mnemonic sentence.

Usage

First, download the repo:

$ git clone https://github.com/derch28/seedsplit.git

The CLI has two functionalities: Split a seedphrase and Rebuild a seedphrase (from the keys you get as a result of splittin it).

Split

$ cargo run -- split [seedphrase]

This gives you 3 key parirs. A1-B1, A2-B2, A3-B3. To get your seedphrase back use rebuild:

Rebuild

$ cargo run -- rebuild [key_1] -- [key_2]

Example

Split

~/seedsplit$ cargo run -- split custom belt rotate wish stove buffalo powder potato material scrap horn cushion
   Compiling seedsplit v0.1.0 (/home/derch/seedsplit)
    Finished dev [unoptimized + debuginfo] target(s) in 3.23s
     Running `target/debug/seedsplit split custom belt rotate wish stove buffalo powder potato material scrap horn cushion`

---------------------------------------------------------------------
A1: vicious mother whip recycle camp winter strong thing middle artwork patch cost
B1: drink luggage scrub emerge remove canvas spirit sight witness reform smoke alarm
---------------------------------------------------------------------
A2: actor gate region guilt grape peanut armor salt alley ancient tent melt
B2: crop regret amateur neutral ill knock outer tuition list rib mixture profit
---------------------------------------------------------------------
A3: toss seven nuclear elbow iron process similar regular obscure child where globe
B3: extend expect ceiling rely gather impulse theory village vague office infant spring
---------------------------------------------------------------------

Rebuild using key pair 1:

~/seedsplit$ cargo run -- rebuild vicious mother whip recycle camp winter strong thing middle artwork patch cost -- drink luggage scrub emerge remove canvas spirit sight witness reform smoke alarm
    Finished dev [unoptimized + debuginfo] target(s) in 0.02s
     Running `target/debug/seedsplit rebuild vicious mother whip recycle camp winter strong thing middle artwork patch cost -- drink luggage scrub emerge remove canvas spirit sight witness reform smoke alarm`

---------------------------------------------------------------------
Seedprhase:custom belt rotate wish stove buffalo powder potato material scrap horn cushion
---------------------------------------------------------------------

Rebuild using key pair 2:

~/seedsplit$ cargo run -- rebuild actor gate region guilt grape peanut armor salt alley ancient tent melt -- crop regret amateur neutral ill knock outer tuition list rib mixture profit
    Finished dev [unoptimized + debuginfo] target(s) in 0.02s
     Running `target/debug/seedsplit rebuild actor gate region guilt grape peanut armor salt alley ancient tent melt -- crop regret amateur neutral ill knock outer tuition list rib mixture profit`

---------------------------------------------------------------------
Seedprhase:custom belt rotate wish stove buffalo powder potato material scrap horn cushion
---------------------------------------------------------------------

Rebuild using key pair 3:

~/seedsplit$ cargo run -- rebuild toss seven nuclear elbow iron process similar regular obscure child where globe -- extend expect ceiling rely gather impulse theory village vague office infant spring
    Finished dev [unoptimized + debuginfo] target(s) in 0.02s
     Running `target/debug/seedsplit rebuild toss seven nuclear elbow iron process similar regular obscure child where globe -- extend expect ceiling rely gather impulse theory village vague office infant spring`

---------------------------------------------------------------------
Seedprhase:custom belt rotate wish stove buffalo powder potato material scrap horn cushion
---------------------------------------------------------------------