Module utils

Utilities to help the process of encoding/decoding a COSE message.

Examples

Examples on how to encode a COSE message by providing the respective parameters and cose-key in JSON format.

The functions decode_json_key and decode_json used in this examples are from the optional feature json of this crate.

cose-sign1

use cose::utils;
use cose::message::{CoseMessage, SIG1_TAG};

fn main() {

    // cose-sign1 message in JSON format
    let data: &str = r#"
    {
            "protected": {"alg": "EDDSA" },
            "unprotected": {"kid": "11" },
            "payload": "signed message"
    }"#;

    // cose-key in JSON format
    let key_json: &str = r#"
    {
            "kty": "OKP",
            "alg": "EDDSA",
            "crv": "Ed25519",
            "x": "d75a980182b10ab7d54bfed3c964073a0ee172f3daa62325af021a68f707511a",
            "d": "9d61b19deffd5a60ba844af492ec2cc44449c5697b326919703bac031cae7f60",
            "key ops": ["sign", "verify"]
    }"#;

    // Decode the cose-key JSON to CoseKey structure
    let key = utils::decode_json_key(key_json).unwrap();
    // Encode the cose-sign1 with the decoded cose-key and cose-sign1 JSON
    let res = utils::decode_json(data, &key, SIG1_TAG).unwrap();

    // Verify the signature
    let mut verify = CoseMessage::new_sign();
    verify.bytes = res;
    verify.init_decoder(None).unwrap();
    verify.key(&key).unwrap();
    verify.decode(None, None).unwrap();
}

cose-encrypt0

use cose::utils;
use cose::message::{CoseMessage, ENC0_TAG};

fn main() {
    // cose-encrypt0 message in JSON format
    let data: &str = r#"
    {
            "protected": {"alg": 24 },
            "unprotected": {"kid": "11", "iv": "000102030405060700010203" },
            "payload": "This is the content."
    }"#;
    // cose-key in JSON format
    let key_json: &str = r#"
    {
            "kty": 4,
            "alg": 24,
            "k": "849b57219dae48de646d07dbb533566e976686457c1491be3a76dcea6c427188",
            "key ops": [3, 4]
    }"#;

    // Decode the cose-key JSON to CoseKey structure
    let key = utils::decode_json_key(key_json).unwrap();
    // Encode the cose-encrypt0 with the decoded cose-key and cose-encrypt0 JSON
    let res = utils::decode_json(data, &key, ENC0_TAG).unwrap();

    // Decrypt and verify
    let mut dec0 = CoseMessage::new_encrypt();
    dec0.bytes = res;
    dec0.init_decoder(None).unwrap();

    dec0.key(&key).unwrap();
    let resp = dec0.decode(None, None).unwrap();
    assert_eq!(resp, b"This is the content.".to_vec());
}

cose-mac0

use cose::utils;
use cose::message::{CoseMessage, MAC0_TAG};

pub fn mac0_json() {
    // cose-mac0 message in JSON format
    let data: &str = r#"
    {
        "protected": {"crit": [1, 2], "alg": 26 },
        "unprotected": {"kid": "11"},
        "payload": "This is the content."
    }"#;

    // cose-key in JSON format
    let key_json: &str = r#"
    {
        "kty": 4,
        "alg": 26,
        "k": "849b57219dae48de646d07dbb533566e976686457c1491be3a76dcea6c427188",
        "key ops": [9, 10]
    }"#;

    // Decode the cose-key JSON to CoseKey structure
    let key = utils::decode_json_key(key_json).unwrap();
    // Encode the cose-mac0 with the decoded cose-key and cose-mac0 JSON
    let res = utils::decode_json(data, &key, MAC0_TAG).unwrap();

    // Verify the MAC tag
    let mut verify = CoseMessage::new_mac();
    verify.bytes = res;
    verify.init_decoder(None).unwrap();

    verify.key(&key).unwrap();
    verify.decode(None, None).unwrap();
}

Functions

cose_type_finder

Function that with a given COSE message bytes, identifies the corresponding message type.