History

Ryan Heywood af230f55df keyfork-shard: limit size of encrypted payload, can fit at max a 256 bit shard		2024-02-10 00:38:48 -05:00
..
src	keyfork-shard: limit size of encrypted payload, can fit at max a 256 bit shard	2024-02-10 00:38:48 -05:00
Cargo.toml	all crates: add documentation	2024-01-15 21:44:48 -05:00
README.md	keyforkd, keyfork-shard: add README.md	2024-01-20 01:17:56 -05:00

README.md

Keyfork Shard

Securing secrets using Shamir's Secret Sharing, an "M-of-N" secret recovery mechanism used to split a secret into n encrypted parts, with m parts required to restore the secret.

Shardfile Formats

Currently, OpenPGP is the only supported format. Any mix of smartcards and OpenPGP key files are supported.

Metadata

Keyfork Shard stores some additional metadata inside the Shardfile to make recombining secrets easier. This metadata currently includes the metadata version (1) and the threshold required to recreate the secret (meaning you don't need to remember the threshold!).

Command Line Usage

The command to run to split and combine a secret is format-dependent, but will often follow the format keyfork-shard-split-<format> and keyfork-shard-combine-<format>. For this example, OpenPGP will be used, but the flow will be similar for any format. Keyfork Shard expects the input to be a hex-encoded secret.

# Read our secret into a shell variable.
read secret

# Shard our secret.
echo $secret | keyfork-shard-split-openpgp 3 5 keyring.pgp > shards.pgp

# Forget our secret.
unset secret

# Recreate our secret. Without specifying a keyring, we are prompted to use
# smartcards.
keyfork-shard-combine-openpgp shards.pgp