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https://github.com/keisentraut/age-keygen-deterministic
simple Rust CLI tool to derive an age private key from passphrase
https://github.com/keisentraut/age-keygen-deterministic
age-encryption
Last synced: about 2 months ago
JSON representation
simple Rust CLI tool to derive an age private key from passphrase
- Host: GitHub
- URL: https://github.com/keisentraut/age-keygen-deterministic
- Owner: keisentraut
- License: bsd-3-clause
- Created: 2022-02-08T21:54:21.000Z (over 2 years ago)
- Default Branch: main
- Last Pushed: 2024-02-11T13:32:34.000Z (8 months ago)
- Last Synced: 2024-06-30T20:35:24.794Z (3 months ago)
- Topics: age-encryption
- Language: Rust
- Homepage:
- Size: 13.7 KB
- Stars: 12
- Watchers: 3
- Forks: 1
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- License: LICENSE
Awesome Lists containing this project
- awesome-age - age-keygen-deterministic
README
# age-keygen-deterministic
This is a very simple Rust CLI tool which deterministically derives a single (or multiple) [age encryption](https://github.com/FiloSottile/age) secret keys from a passphrase.
I use this because I use age for long-term backup and want to be able to restore my backup files even if my house burns down and I lost all copies of the secret key - but still remember the passphrase.
## Disclaimer
I am not a professional cryptographer and have not done any review of the third-party dependencies.
Use at your own risk.
**The output of this utility should be piped directly into ```age-keygen -y``` and only the public key should be stored permanently.**
If you run this utility repeatedly inside scripts or pipe the secret key directly to ```age -i- -d ...```, then you are most likely doing something stupid and will leak your passphrase.
## Compile
This utility is written in Rust.
Just clone this repository and then run ```cargo build```.
## Usage
```
USAGE:
age-keygen-deterministic [OPTIONS]
FLAGS:
-h, --help Prints help information
-V, --version Prints version information
OPTIONS:
-c, --count optional number of secret keys which should be created [default: 1]
-o, --offset optional u64 offset for index of keys [default: 0]
```
If you only need a single age key, just use it without any command line arguments.
If you want to generate more than one secret key, then you can simply use the ```--count``` argument.
## Example run
If you use the passphrase ```example-passphrase-do-not-use!``` and want to generate the deterministic secret keys #2, #3 and #4, then just run the commands below:
```
$ cargo build --release
$ ./target/release/age-keygen-deterministic -c 3 -o 2
Enter passphrase:
# secret key 2 below
AGE-SECRET-KEY-1RSWAHJR48AWPN6HHTVVGXN7X3X0YWWA7TM7H22T7TF35EZPPVHHQ7WYGRZ
# secret key 3 below
AGE-SECRET-KEY-144T9ZKX0HK6CMMGYEN6WPN82Q4K9LVR376NUJF33HKVAQ70TXMHSPV96MY
# secret key 4 below
AGE-SECRET-KEY-1FMPVFDE9WD8CSTNS4J3QRNQ5VRTFE8973FVJ2JANT56HEPZTKA4SQZZ84R
```
The public key for any of those private keys can be obtained by piping the secret key to ```age-keygen -y```.
```
$ echo AGE-SECRET-KEY-1VZ3CREDN87LLHYDVS6FK36EZEVWNZGGFFSWZDN7DL0J04WG723MQCZUS9Q | age-keygen -y
age1z568mysf7kulsml0rxt6vxp3h26hjmgcmdpz8x6dfh0zlazspquqqawzn4
```
## Cryptography
Please note that you should specify at least 256 bits of entropy.
This program will accept a passphrase with only 16 characters but in general you should use longer ones.
The passphrase is stretched with Argon2id to a 64 byte master key.
Afterwards, secret keys are generated by incrementing a u64 counter ```i``` and using ```HMAC_SHA256(master_key, i)``` for the age secret keys.
Each 32 byte HMAC-SHA256 output is converted to Bech32 format and written to stdout.
Please note that there are some **cryptographic limitations** which this toy project does not care about:
- This program does not attempt to clear any secrets from RAM before it exits.
- This program does not make any guarantees about side-channel resistance.
- No clamping of the X25519 key is done - but as far as I know, ```age-keygen``` doesn't do it either.