gen-key

Crates.io	gen-key
lib.rs	gen-key
version	0.2.0
created_at	2025-06-20 21:48:04.047953+00
updated_at	2025-06-21 10:00:27.229809+00
description	Small CLI tool for generating RSA and HMAC keys
homepage
repository	https://github.com/grapple228/rust_gen_key.git
max_upload_size
id	1720323
size	61,099

Green Apple (Grapple228)

documentation

README

Key Generation Tool

This is a simple command-line tool for generating RSA and HMAC keys. The generated keys can be output to the console or saved to files in a specified directory.

Important

⚠️ Security Notice:
This tool uses the rsa crate, which is affected by RUSTSEC-2023-0071.
Do not use this tool for generating production or long-term RSA keys until the issue is resolved.
For production, use OpenSSL or another well-audited cryptography library.

Features

Generate RSA key pairs (private and public keys).
Generate HMAC keys.
Output keys in PEM or DER format (for RSA only).
Save keys to a specified directory or print them to stdout.

Installation

To build and run the tool, ensure you have Rust and Cargo installed. Clone the repository and run:

From source

cargo install --git https://github.com/grapple228/rust_gen_key.git

From crates.io

cargo install gen-key

Key formats

RSA private keys are saved in PKCS#8 format (both PEM and DER), public keys are saved in X.509 (SPKI) format. HMAC keys are saved as raw bytes (or base64url when printed to stdout).

Usage

The tool can be run with various command-line options. Below are some examples of how to use it:

Display help message

gen-key --help

Generate RSA Key Pair

To generate a 2048-bit RSA key pair and print to stdout:

gen-key --stdout

To generate a 4096-bit RSA key pair, print to stdout, and save to ./mykeys/:

gen-key --alg rsa -k 4096 -o ./mykeys --stdout

Generate HMAC Key

To generate a 512-bit HMAC key and print as base64 to stdout:

gen-key --alg hmac -k 512

Save key to directory as files

To save PEM-formatted RSA keys to ./certs/ only:

gen-key --alg rsa -o ./certs

To print DER-formatted RSA keys as base64 to stdout and save to ./certs/:

gen-key --alg rsa --stdout -o ./certs -f der

To print with custom name:

gen-key --alg rsa --stdout -o ./certs -f der -p custom

Command-Line Options

Short	Long	Description	Values / Notes
	`--alg`	Specify the algorithm	`rsa [default]`, `hmac`
`-k`	`--key-size`	Specify the key size in bits	RSA: `2048 [default]`, `3072`, `4096` HMAC: `256 [default]`, `384`, `512`
`-o`	`--out-dir`	Output directory for saving keys	Path to directory. If set and `--stdout` is not, then it will only save files
`-p`	`--prefix`	Keys will be created with prefix	Could be as `default [default]` or non-empty string. RSA:`rsa.pub` and `rsa.pub.der` HMAC: `hmac.key`
	`--stdout`	Print generated key(s) to stdout	No value needed. Enables printing keys to stdout
`-f`	`--format`	Output format for RSA keys	`pem [default]`, `der`
	`--line-ending`	Set line ending for `.pem` files	`crlf [default]`, `cr`, `lf`
`-r`	`--replace`	Replace file if exists in `--out-dir`	`false` by default and will throw an error if file exists
`-h`	`--help`	Show help message

Notes

If both --stdout and --out-dir are set, keys will be output to both locations
If --stdout is not set and --out-dir is not set, keys will be printed into stdout by default

Example output

When generating keys, the tool will provide feedback in the console, indicating the status of key generation and where the keys are saved.

RSA (to console):

$ gen-key
Generating RSA key pair with size 2048...
-----BEGIN PRIVATE KEY-----
... KEY HERE ...
-----END PRIVATE KEY-----

-----BEGIN PUBLIC KEY-----
... KEY HERE ...
-----END PUBLIC KEY-----

HMAC (to console):

$ gen-key --alg hmac
Generating HMAC key with 32 bytes...
HMAC key (base64url):
XFMH-E2lXaBHC0_7ZyiqHiAM1kfQ7aGqTnCSnrU-pPc

RSA (to file):

$ gen-key -o ./certs/
Generating RSA key pair with size 2048...
Saving keys to ./certs/
RSA private key saved to ./certs/rsa
RSA public key saved to ./certs/rsa.pub

HMAC (to file):

$ gen-key -o ./certs/ --alg hmac
Generating HMAC key with 32 bytes...
Saving key to ./certs/
HMAC key saved to ./certs/hmac.key

Contributing

Contributions are welcome! If you have suggestions for improvements or new features, feel free to open an issue or submit a pull request. I wrote this tool for my own use, so it may not fit everyone's needs, but your input is appreciated!

Future plans

Add support for generating ECC keys

License

This project is licensed under the MIT License. See the LICENSE file for details.

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