8 stable releases
1.4.2 | Oct 10, 2023 |
---|---|
1.4.1 | Mar 9, 2023 |
1.4.0 | Feb 27, 2023 |
1.2.1 | Jan 31, 2023 |
1.1.0 | Oct 31, 2022 |
#185 in Cryptography
21 downloads per month
92KB
2K
SLoC
keygate-jwt
A new JWT (JSON Web Tokens) implementation for Rust that focuses on simplicity while avoiding common JWT security pitfalls.
keygate-jwt
is opinionated and only supports secure signature algorithms:
JWT algorithm name | Feature | Description |
---|---|---|
EdDSA |
eddsa |
Ed25519 (Recommended) |
ES256 |
ecdsa |
ECDSA over p256 / SHA-256 |
ES384 |
ecdsa |
ECDSA over p384 / SHA-384 |
ES256K |
ecdsa |
ECDSA over secp256k1 / SHA-256 |
Whenever possible, you should use EdDSA
, however not all JWT libraries support it yet, so ecdsa
is also supported.
keygate-jwt
uses only pure Rust implementations and can be compiled out of the box to WebAssembly/WASI.
Important: JWT's purpose is to verify that data has been created by a party knowing a secret key. It does not provide any confidentiality: JWT data is simply encoded as BASE64 and is not encrypted.
Usage
cargo.toml
:
[dependencies]
keygate-jwt = "1.0"
Errors are returned as keygate-jwt::Error
values
Signatures
A signature requires a key pair: a secret key used to create tokens and a public key that can only verify them.
Always use a signature scheme if both parties do not ultimately trust each other, such as tokens exchanged between clients and API providers.
Key pairs and tokens creation
Key creation:
ES256
use keygate_jwt::prelude::*;
// create a new key pair for the `ES256` JWT algorithm
let key_pair = ES256KeyPair::generate();
// a public key can be extracted from a key pair:
let public_key = key_pair.public_key();
ES384
use keygate_jwt::prelude::*;
// create a new key pair for the `ES384` JWT algorithm
let key_pair = ES384KeyPair::generate();
// a public key can be extracted from a key pair:
let public_key = key_pair.public_key();
Keys can be exported as bytes for later reuse and imported from bytes or, for RSA, from individual parameters, DER-encoded or PEM-encoded data.
RSA key pair creation, using OpenSSL and PEM importation of the secret key:
openssl genrsa -out private.pem 2048
openssl rsa -in private.pem -outform PEM -pubout -out public.pem
let key_pair = RS384KeyPair::from_pem(private_pem_file_content)?;
let public_key = RS384PublicKey::from_pem(public_pem_file_content)?;
Token creation and verification work the same way as with HS*
algorithms, except that tokens are created with a key pair and verified using the corresponding public key.
Token creation:
/// create claims valid for 2 hours
let claims = Claims::create(Duration::from_hours(2));
let token = key_pair.sign(claims)?;
Token verification:
let claims = public_key.verify_token::<NoCustomClaims>(&token, None)?;
Available verification options are identical to the ones used with symmetric algorithms.
Advanced usage
Custom claims
Claim objects support all the standard claims by default, and they can be set directly or via convenient helpers:
let claims = Claims::create(Duration::from_hours(2)).
with_issuer("Example issuer").with_subject("Example subject");
You can also define your own claims. These have to be present in a serializable type (this requires the serde
crate):
#[derive(Serialize, Deserialize)]
struct MyAdditionalData {
user_is_admin: bool,
user_country: String,
}
let my_additional_data = MyAdditionalData {
user_is_admin: false,
user_country: "FR".to_string(),
};
Claim creation with custom data:
let claims = Claims::with_custom_claims(my_additional_data, Duration::from_secs(30));
Claim verification with custom data. Note the presence of the custom data type:
let claims = public_key.verify_token::<MyAdditionalData>(&token, None)?;
let user_is_admin = claims.custom.user_is_admin;
Peeking at metadata before verification
Properties such as the key identifier can be helpful before tag or signature verification to pick the right key out of a set.
let metadata = Token::decode_metadata(&token)?;
let key_id = metadata.key_id();
let algorithm = metadata.algorithm();
// all other standard properties are also accessible
IMPORTANT: You can't trust the key ID, nor the algorithm
As a result, algorithm
should be used only for debugging purposes and never to select a key type.
Similarly, key_id
should be used only to select a key in a set of keys for the same algorithm.
Mitigations against replay attacks
keygate-jwt
includes mechanisms to mitigate replay attacks:
- Nonces can be attached to new tokens using the
with_nonce()
claim function. The verification procedure can later reject any token that doesn't include the expected nonce (required_nonce
verification option). - The verification procedure can reject tokens created too long ago, no matter their expiration date. This prevents tokens from malicious (or compromised) signers from being used too long.
- The verification procedure can reject tokens created before a date. For a given user, the date of the last successful authentication can be stored in a database and used later, along with this option, to reject older (replayed) tokens.
Why yet another JWT crate
There are already several JWT crates for Rust, but none of them satisfied our needs:
- no insecure algorithms (such as
RSA
orHS256
) and hash functions (such asSHA1
) are supported - minimal, rust-only dependencies
Credits
This crate is based on the jwt-simple project by Frank Denis. Notable changes include introducing cargo feature flags and unneeded dependencies and removing support for insecure algorithms. 1
Dependencies
~1.2–3MB
~66K SLoC