agree

\ agree is a CLI tool for easily applying multi-key-turn security via Shamirs Secret Sharing.

Project state

agree is unstable.\ Version semantics: ^([0-9]+\.[0-9]+\.[0-9]+)(-(alpha|beta)\.[0-9]+)?$.

Example

Split a secret into n shares (interactive)

To split a secret (file) into shares, execute one of the following examples.:

• Data is in a file (Cargo.toml): \ agree interactive split -s Cargo.toml
• Data is generated by an inline shell script and written to STDOUT (this approach uses process substitution): \ agree interactive split -s <(printf "secret")

This command is interactive and asks the user to provide data like s hare name, file path and optional password to encrypt the share data.

Restore a secret from n shares (interactive)

In the following example, the secret was split into 2 shares. We need to provide exactly two shares in order to restore the secret and write it to STDOUT.\ This command is interactive as it might prompt for the password of the share if it's share dataa is encrypted.

agree interactive restore -s ./share1.file -s ./share2.file

Split a secret into n shares (via blueprint)

The example below will split the secret into three shares with a restore threshold of two. Assuming the file is called blueprint.yaml, we can use the following command:

bash agree headless split -s `Cargo.toml` -b `blueprint.yaml`

```yaml threshold: 2 generate: - path: ./test/alice.share - path: ./test/bob.share name: bob encrypt: !plain example-bob info: true comment: example for bob - path: ./test/charlie.share name: charlie encrypt: !shell printf example-charlie

```

Share composition

In all version, bytes [0..36) are reserved for the version ID of the archive.\ In the following schematics, only the data from index [36..] is used and shifted left to index 0 for convenience.

1f2c6a6d-f711-4378-97b9-5f9e2f9f4271kldmf209fm0f944fwef98syf23f9h2fneuf2efhux... ^ -- -- VERSION ID -- -- ^ DATA =>

v0.1

v0.1 is a yaml base64 encoded YAML file. The share information can be store either in plain text or can be protected with a password. The share data is always base64 encoded when stored in the YAML field.\ If encrypted with a password, a symmetric encryption algorithm with the following attributes is used (from the crate simplecrypt v 1.0.2):

/// |index |usage| /// |-------|-----| /// |0 - 15 |salt | /// |16 - 39|nonce| /// |40 - 55|mac | /// |56 - |data |

The password to the data is hashed via argon2. The hashed password is stored alongside the encrypted data to easily identify wrong passwords when the data is decrypted.