COSEMessage
Last updated
Last updated
The COSEMessage class encapsulates the structure and functionality of COSE messages within the Uniot project. It leverages the class for handling CBOR-encoded data and integrates with cryptographic libraries (such as Ed25519) to provide robust signing and verification mechanisms. The class supports the creation, manipulation, signing, and verification of COSE_Sign1 messages, ensuring data integrity and authenticity in communications.
Constructor and Destructor:
COSEMessage()
Constructs an empty COSEMessage instance. Initializes a new COSE_Sign1 message, setting up protected and unprotected headers, payload, and signature fields.
COSEMessage(Bytes buf)
Constructs a COSEMessage instance from a given byte buffer. Parses the provided byte buffer to populate the COSE_Sign1 message fields. Sets the read success flag based on the parsing outcome.
virtual ~COSEMessage()
Destructor that cleans up the COSE message. Frees allocated resources and resets internal pointers to prevent memory leaks.
Message Handling:
bool read(const Bytes &buf)
Decodes the byte buffer and extracts the protected header, unprotected header, payload, and signature fields. Validates the structure and content of the COSE message.
bool wasReadSuccessful() const
Checks if the last read operation was successful.
Header Manipulation:
Bytes getProtectedHeader()
Extracts the protected header portion of the COSE message for inspection or modification.
CBORObject getUnprotectedHeader()
Provides access to the unprotected headers, allowing for the addition or modification of header fields.
Bytes getUnprotectedKid()
Extracts the Key Identifier (kid) used for identifying the key associated with the COSE message.
Payload and Signature:
Bytes getPayload()
Retrieves the payload of the COSE message.
Bytes getSignature()
Retrieves the signature of the COSE message.
Signing and Verification:
void sign(const ICOSESigner &signer, const Bytes &external = Bytes())
Signs the COSE message using the provided signer.
signer (const ICOSESigner &): The signer object implementing the interface.
external (const Bytes &, optional): External Additional Authenticated Data (AAD) to include in the signature.
bool verify(const Bytes &publicKey)
Verifies the signature of the COSE message using the provided public key.
Serialization:
Bytes build() const
Serializes the COSEMessage into a byte buffer.
State Management:
bool isSigned()
Checks if the COSE message has been signed.
void clean()
Resets the COSEMessage to its initial state.
Private Methods:
bool _read(const Bytes &buf)
Internal method to parse a byte buffer and populate the COSE message fields.
void _create()
Initializes the internal CBOR structure for a new COSE_Sign1 message.
void _clean()
Cleans up the internal CBOR structure and resets pointers.
bool _setProtectedHeader(const CBORObject &pHeader)
Sets the protected header of the COSE message.
bool _setSignature(const Bytes &signature)
Sets the signature of the COSE message.
Bytes _toBeSigned(const Bytes &external = Bytes())
Builds the Sig_structure as defined in the COSE specification, which includes the context, protected header, external AAD, and payload. This sequence is what the signer uses to generate the signature.
external (const Bytes &, optional): External Additional Authenticated Data (AAD) to include in the signature.