Crate ssh_key

Expand description

§RustCrypto: SSH Keys and Certificates

§About

Pure Rust implementation of SSH key file format decoders/encoders as described in RFC4251 and RFC4253 as well as OpenSSH’s PROTOCOL.key format specification.

Additionally provides support for SSH signatures as described in PROTOCOL.sshsig, OpenSSH certificates as specified in PROTOCOL.certkeys including certificate validation and certificate authority (CA) support, FIDO/U2F keys as specified in PROTOCOL.u2f (and certificates thereof), and also the authorized_keys and known_hosts file formats.

Supports a minimal profile which works on heapless no_std targets. See “Supported algorithms” table below for which key formats work on heapless targets and which algorithms require alloc.

When the ed25519, p256, and/or rsa features of this crate are enabled, provides key generation and certificate signing/verification support for that respective SSH key algorithm.

§Features

Constant-time Base64 decoder/encoder using base64ct/pem-rfc7468 crates
OpenSSH-compatible decoder/encoders for the following formats:
- OpenSSH public keys
- OpenSSH private keys (i.e. BEGIN OPENSSH PRIVATE KEY)
- OpenSSH certificates
- OpenSSH signatures (a.k.a. “sshsig”)
OpenSSH certificate support
- OpenSSH certificate validation
- OpenSSH certificate authority (CA) support i.e. cert builder/signer
Private key encryption/decryption (bcrypt-pbkdf + aes256-ctr only)
Private key generation support: DSA, Ed25519, ECDSA (P-256/P-384/P-521), and RSA
FIDO/U2F key support (sk-*) as specified in PROTOCOL.u2f
Fingerprint support
- “randomart” fingerprint visualizations
no_std support including support for “heapless” (no-alloc) targets
Parsing authorized_keys files
Parsing known_hosts files
serde support
zeroize support for private keys

§TODO

FIDO/U2F signature support
Legacy (pre-OpenSSH) SSH key format support
- PKCS#1 SSH private keys (i.e. RSA-only)
- PKCS#8 SSH private keys
- RFC4716 SSH public keys
- SEC1 SSH public keys

§Supported Signature Algorithms

Name	Decode	Encode	Cert	Keygen	Sign	Verify	Feature	`no_std`
`ecdsa‑sha2‑nistp256`	✅	✅	✅	✅️	✅️	✅️	`p256`	heapless
`ecdsa‑sha2‑nistp384`	✅	✅	✅	✅️	✅️	✅️	`p384`	heapless
`ecdsa‑sha2‑nistp521`	✅	✅	✅	✅️️	✅️ ️	✅️️	`p521`	heapless
`ssh‑dsa`	✅	✅	✅	✅	✅️	✅️	`dsa`	`alloc` ️
`ssh‑ed25519`	✅	✅	✅	✅️	✅️	✅	`ed25519`	heapless
`ssh‑rsa`	✅	✅	✅	✅️	✅️	✅	`rsa`	`alloc`
`sk‑ecdsa‑sha2‑nistp256@openssh.com`	✅	✅	✅	⛔	⛔️	✅️	⛔	`alloc`
`sk‑ssh‑ed25519@openssh.com`	✅	✅	✅	⛔	⛔️	✅️️	`ed25519`	`alloc`

By default no SSH signature algorithms are enabled and you will get an Error::AlgorithmUnsupported error if you try to use them.

Enable the crypto feature or the “Feature” for specific algorithms in the chart above (e.g. p256, rsa) in order to use cryptographic functionality.

The “Feature” column lists the name of ssh-key crate features which can be enabled to provide full support for the “Keygen”, “Sign”, and “Verify” functionality for a particular SSH key algorithm.

§Minimum Supported Rust Version

This crate requires Rust 1.65 at a minimum.

We may change the MSRV in the future, but it will be accompanied by a minor version bump.

§License

Licensed under either of:

at your option.

§Contribution

Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in the work by you, as defined in the Apache-2.0 license, shall be dual licensed as above, without any additional terms or conditions.

§Usage

The main types provided by this library are:

Certificate: OpenSSH certificates
Fingerprint: public key fingerprints (i.e. hashes)
PrivateKey: SSH private keys (i.e. digital signature keys)
PublicKey: SSH public keys (i.e. signature verification keys)
SshSig: signatures with SSH keys ala ssh-keygen -Y sign/ssh-keygen -Y verify

§Parsing OpenSSH Public Keys

OpenSSH-formatted public keys have the form:

<algorithm id> <base64 data> <comment>

§Example

use ssh_key::PublicKey;

let encoded_key = "ssh-ed25519 AAAAC3NzaC1lZDI1NTE5AAAAILM+rvN+ot98qgEN796jTiQfZfG1KaT0PtFDJ/XFSqti user@example.com";
let public_key = PublicKey::from_openssh(encoded_key)?;

// Key attributes
assert_eq!(public_key.algorithm(), ssh_key::Algorithm::Ed25519);
assert_eq!(public_key.comment(), "user@example.com");

// Key data: in this example an Ed25519 key
if let Some(ed25519_public_key) = public_key.key_data().ed25519() {
    assert_eq!(
        ed25519_public_key.as_ref(),
        [
            0xb3, 0x3e, 0xae, 0xf3, 0x7e, 0xa2, 0xdf, 0x7c, 0xaa, 0x1, 0xd, 0xef, 0xde, 0xa3,
            0x4e, 0x24, 0x1f, 0x65, 0xf1, 0xb5, 0x29, 0xa4, 0xf4, 0x3e, 0xd1, 0x43, 0x27, 0xf5,
            0xc5, 0x4a, 0xab, 0x62
        ].as_ref()
    );
}

§Parsing OpenSSH Private Keys

NOTE: for more private key usage examples, see the private module.

OpenSSH-formatted private keys are PEM-encoded and begin with the following:

-----BEGIN OPENSSH PRIVATE KEY-----

§Example

use ssh_key::PrivateKey;

// WARNING: don't actually hardcode private keys in source code!!!
let encoded_key = r#"
-----BEGIN OPENSSH PRIVATE KEY-----
b3BlbnNzaC1rZXktdjEAAAAABG5vbmUAAAAEbm9uZQAAAAAAAAABAAAAMwAAAAtzc2gtZW
QyNTUxOQAAACCzPq7zfqLffKoBDe/eo04kH2XxtSmk9D7RQyf1xUqrYgAAAJgAIAxdACAM
XQAAAAtzc2gtZWQyNTUxOQAAACCzPq7zfqLffKoBDe/eo04kH2XxtSmk9D7RQyf1xUqrYg
AAAEC2BsIi0QwW2uFscKTUUXNHLsYX4FxlaSDSblbAj7WR7bM+rvN+ot98qgEN796jTiQf
ZfG1KaT0PtFDJ/XFSqtiAAAAEHVzZXJAZXhhbXBsZS5jb20BAgMEBQ==
-----END OPENSSH PRIVATE KEY-----
"#;

let private_key = PrivateKey::from_openssh(encoded_key)?;

// Key attributes
assert_eq!(private_key.algorithm(), ssh_key::Algorithm::Ed25519);
assert_eq!(private_key.comment(), "user@example.com");

// Key data: in this example an Ed25519 key
if let Some(ed25519_keypair) = private_key.key_data().ed25519() {
   assert_eq!(
       ed25519_keypair.public.as_ref(),
       [
           0xb3, 0x3e, 0xae, 0xf3, 0x7e, 0xa2, 0xdf, 0x7c, 0xaa, 0x1, 0xd, 0xef, 0xde, 0xa3,
           0x4e, 0x24, 0x1f, 0x65, 0xf1, 0xb5, 0x29, 0xa4, 0xf4, 0x3e, 0xd1, 0x43, 0x27, 0xf5,
           0xc5, 0x4a, 0xab, 0x62
       ].as_ref()
   );

   assert_eq!(
       ed25519_keypair.private.as_ref(),
       [
           0xb6, 0x6, 0xc2, 0x22, 0xd1, 0xc, 0x16, 0xda, 0xe1, 0x6c, 0x70, 0xa4, 0xd4, 0x51,
           0x73, 0x47, 0x2e, 0xc6, 0x17, 0xe0, 0x5c, 0x65, 0x69, 0x20, 0xd2, 0x6e, 0x56, 0xc0,
           0x8f, 0xb5, 0x91, 0xed
       ].as_ref()
   )
}

§`serde` support

When the serde feature of this crate is enabled, the Certificate, Fingerprint, and PublicKey types receive impls of serde’s Deserialize and Serialize traits.

Serializing/deserializing PrivateKey using serde is presently unsupported.

Re-exports§

pub use crate::authorized_keys::AuthorizedKeys;
pub use crate::private::PrivateKey;
pub use crate::public::PublicKey;
pub use crate::certificate::Certificate;
alloc
pub use crate::known_hosts::KnownHosts;
alloc
pub use sha2;
pub use sec1;
ecdsa
pub use rand_core;
rand_core

Modules§

authorized_keys
Parser for AuthorizedKeysFile-formatted data.
certificatealloc
OpenSSH certificate support.
known_hostsalloc
Parser for KnownHostsFile-formatted data.
private
SSH private key support.
public
SSH public key support.

Structs§

AlgorithmNamealloc
A string representing an additional algorithm name in the name@domainname format (see RFC4251 § 6).
Mpintalloc
Multiple precision integer, a.k.a. “mpint”.
Signaturealloc
Low-level digital signature (e.g. DSA, ECDSA, Ed25519).
SshSigalloc
sshsig provides a general-purpose signature format based on SSH keys and wire formats.

Enums§

Algorithm
SSH key algorithms.
Cipher
Cipher algorithms.
EcdsaCurve
Elliptic curves supported for use with ECDSA.
Error
Error type.
Fingerprint
SSH public key fingerprints.
HashAlg
Hashing algorithms a.k.a. digest functions.
Kdf
Key Derivation Functions (KDF).
KdfAlg
Key Derivation Function (KDF) algorithms.
LineEnding
Line endings: variants of newline characters that can be used with Base64.

Traits§

SigningKeyalloc
Trait for signing keys which produce a Signature.

Type Aliases§

Result
Result type with ssh-key’s Error as the error type.

Crate ssh_keyCopy item path

§RustCrypto: SSH Keys and Certificates

§About

§Features

§TODO

§Supported Signature Algorithms

§Minimum Supported Rust Version

§License

§Contribution

§Usage

§Parsing OpenSSH Public Keys

§Example

§Parsing OpenSSH Private Keys

§Example

§serde support

Re-exports§

Modules§

Structs§

Enums§

Traits§

Type Aliases§

Crate ssh_key

§`serde` support