Crate coset

Set of types for supporting CBOR Object Signing and Encryption (COSE).

Builds on the serde_cbor crate for underlying CBOR support.

Usage

use coset::{iana, CborSerializable};

// Inputs.
let pt = b"This is the content";
let aad = b"this is additional data";

// Build a `CoseSign1` object.
let protected = coset::HeaderBuilder::new()
    .algorithm(iana::Algorithm::ES256)
    .key_id(b"11".to_vec())
    .build();
let sign1 = coset::CoseSign1Builder::new()
    .protected(protected)
    .payload(pt.to_vec())
    .create_signature(aad, |pt| signer.sign(pt)) // closure to do sign operation
    .build();

// Serialize to bytes.
let sign1_data = sign1.to_vec().unwrap();
println!(
    "'{}' + '{}' => {}",
    String::from_utf8_lossy(pt),
    String::from_utf8_lossy(aad),
    hex::encode(sign1.to_vec().unwrap())
);

// At the receiving end, deserialize the bytes back to a `CoseSign1` object.
let mut sign1 = coset::CoseSign1::from_slice(&sign1_data).unwrap();

// Check the signature, which needs to have the same `aad` provided, by
// providing a closure that can do the verify operation.
let result = sign1.verify_signature(aad, |sig, data| verifier.verify(sig, data));
println!("Signature verified: {:?}.", result);
assert!(result.is_ok());

// Changing an unprotected header leaves the signature valid.
sign1.unprotected.content_type = Some(coset::ContentType::Text("text/plain".to_owned()));
assert!(sign1
    .verify_signature(aad, |sig, data| verifier.verify(sig, data))
    .is_ok());

// Providing a different `aad` means the signature won't validate.
assert!(sign1
    .verify_signature(b"not aad", |sig, data| verifier.verify(sig, data))
    .is_err());

// Changing a protected header invalidates the signature.
sign1.protected.content_type = Some(coset::ContentType::Text("text/plain".to_owned()));
assert!(sign1
    .verify_signature(aad, |sig, data| verifier.verify(sig, data))
    .is_err());

Modules

iana	Enumerations for IANA-managed values.

Structs

CoseEncrypt	Structure representing an encrypted object.
CoseEncrypt0	Structure representing an encrypted object.
CoseEncrypt0Builder	Builder for CoseEncrypt0 objects.
CoseEncryptBuilder	Builder for CoseEncrypt objects.
CoseKdfContext	Structure representing a a key derivation context.
CoseKdfContextBuilder	Builder for CoseKdfContext objects.
CoseKey	Structure representing a cryptographic key.
CoseKeyBuilder	Builder for CoseKey objects.
CoseMac	Structure representing a message with authentication code (MAC).
CoseMac0	Structure representing a message with authentication code (MAC) where the relevant key is implicit.
CoseMac0Builder	Builder for CoseMac0 objects.
CoseMacBuilder	Builder for CoseMac objects.
CoseRecipient	Structure representing the recipient of encrypted data.
CoseRecipientBuilder	Builder for CoseRecipient objects.
CoseSign	Signed payload with signatures.
CoseSign1	Signed payload with a single signature.
CoseSign1Builder	Builder for CoseSign1 objects.
CoseSignBuilder	Builder for CoseSign objects.
CoseSignature	Structure representing a cryptographic signature.
CoseSignatureBuilder	Builder for CoseSignature objects.
Header	Structure representing a common COSE header map.
HeaderBuilder	Builder for Header objects.
PartyInfo	Structure representing a party involved in key derivation.
PartyInfoBuilder	Builder for PartyInfo objects.
SuppPubInfo	Structure representing supplemental public information.
SuppPubInfoBuilder	Builder for SuppPubInfo objects.

Enums

EncryptionContext	Possible encryption contexts.
Label	A COSE label may be either a signed integer value or a string.
MacContext	Possible MAC contexts.
Nonce	A nonce value.
RegisteredLabel	A COSE label which can be either a signed integer value or a string, but where the allowed integer values are governed by IANA.
RegisteredLabelWithPrivate	A COSE label which can be either a signed integer value or a string, and where the allowed integer values are governed by IANA but include a private use range.
SignatureContext	Possible signature contexts.

Traits

CborSerializable	Extension trait that adds serialization/deserialization methods.
TaggedCborSerializable	Extension trait that adds tagged serialization/deserialization methods.

Functions

enc_structure_data	Create a binary blob that will be signed.
mac_structure_data	Create a binary blob that will be signed.
sig_structure_data	Create a binary blob that will be signed.

Type Definitions

Algorithm	Algorithm identifier.
ContentType	Content type.
CoseKeySet	A collection of CoseKey objects.