File syn_cose.c¶

FileList > proto > syn_cose.c

Zero-Heap CBOR Object Signing and Encryption (COSE - RFC 9052) implementation.

#include "syntropic/proto/syn_cose.h"
#include "syntropic/util/syn_random.h"
#include <string.h>

Public Functions¶

Type	Name
SYN_Status	syn_cose_encrypt0_create (SYN_COSE_Algorithm alg, const uint8_t * key, const uint8_t * iv, size_t iv_len, const uint8_t * kid, size_t kid_len, const uint8_t * plaintext, size_t plaintext_len, const uint8_t * external_aad, size_t external_aad_len, uint8_t * out_buf, size_t out_buf_size, size_t * out_len) Encrypt a payload into a COSE_Encrypt0 (Tag 16) message using ChaCha20/Poly1305.
SYN_Status	syn_cose_encrypt0_decrypt (const uint8_t * msg, size_t msg_len, const uint8_t * key, const uint8_t * external_aad, size_t external_aad_len, uint8_t * out_plaintext, size_t out_plaintext_size, size_t * out_plaintext_len, SYN_COSE_Encrypt0Message * parsed_out) Decrypt and verify a COSE_Encrypt0 message.
SYN_Status	syn_cose_key_decode (const uint8_t * buf, size_t buf_len, SYN_COSE_Key * key_out) Decode a CBOR-encoded COSE_Key map into a SYN_COSE_Key structure.
SYN_Status	syn_cose_key_encode (const SYN_COSE_Key * key, uint8_t * out_buf, size_t out_buf_size, size_t * out_len) Encode a COSE_Key structure into CBOR format.
SYN_Status	syn_cose_mac0_create (SYN_COSE_Algorithm alg, const uint8_t * key, size_t key_len, const uint8_t * kid, size_t kid_len, const uint8_t * payload, size_t payload_len, const uint8_t * external_aad, size_t external_aad_len, uint8_t * out_buf, size_t out_buf_size, size_t * out_len) Create a COSE_Mac0 (Tag 17) message using HMAC-SHA256.
SYN_Status	syn_cose_mac0_verify (const uint8_t * msg, size_t msg_len, const uint8_t * key, size_t key_len, const uint8_t * external_aad, size_t external_aad_len, SYN_COSE_Mac0Message * parsed_out) Verify a COSE_Mac0 message using HMAC-SHA256.
SYN_Status	syn_cose_sign1_create (SYN_COSE_Algorithm alg, const uint8_t * secret_key, const uint8_t * public_key, const uint8_t * kid, size_t kid_len, const uint8_t * payload, size_t payload_len, const uint8_t * external_aad, size_t external_aad_len, uint8_t * out_buf, size_t out_buf_size, size_t * out_len) Create a COSE_Sign1 (Tag 18) message signed with EdDSA (Ed25519) or ES256 (P-256).
SYN_Status	syn_cose_sign1_verify (const uint8_t * msg, size_t msg_len, const uint8_t * public_key, size_t public_key_len, const uint8_t * external_aad, size_t external_aad_len, SYN_COSE_Sign1Message * parsed_out) Parse and verify a COSE_Sign1 message using the signer's public key.

Public Functions Documentation¶

function syn_cose_encrypt0_create¶

Encrypt a payload into a COSE_Encrypt0 (Tag 16) message using ChaCha20/Poly1305.

SYN_Status syn_cose_encrypt0_create (
    SYN_COSE_Algorithm alg,
    const uint8_t * key,
    const uint8_t * iv,
    size_t iv_len,
    const uint8_t * kid,
    size_t kid_len,
    const uint8_t * plaintext,
    size_t plaintext_len,
    const uint8_t * external_aad,
    size_t external_aad_len,
    uint8_t * out_buf,
    size_t out_buf_size,
    size_t * out_len
)

Parameters:

alg Encryption algorithm (SYN_COSE_ALGO_CHACHA20_POLY1305).
key Symmetric key (32 bytes).
iv Nonce / IV (12 bytes for ChaCha20/Poly1305).
iv_len IV length.
kid Optional key identifier (NULL if unused).
kid_len Key identifier length.
plaintext Plaintext payload to encrypt.
plaintext_len Plaintext length.
external_aad Optional external associated data (NULL if unused).
external_aad_len External AAD length.
out_buf [out] Output buffer for encoded COSE_Encrypt0 message.
out_buf_size Capacity of output buffer.
out_len [out] Number of bytes written to output buffer.

Returns:

SYN_Status SYN_OK on success, error code otherwise.

function syn_cose_encrypt0_decrypt¶

Decrypt and verify a COSE_Encrypt0 message.

SYN_Status syn_cose_encrypt0_decrypt (
    const uint8_t * msg,
    size_t msg_len,
    const uint8_t * key,
    const uint8_t * external_aad,
    size_t external_aad_len,
    uint8_t * out_plaintext,
    size_t out_plaintext_size,
    size_t * out_plaintext_len,
    SYN_COSE_Encrypt0Message * parsed_out
)

Parameters:

msg Raw COSE_Encrypt0 CBOR encoded message.
msg_len Message length.
key Symmetric key (32 bytes).
external_aad Optional external associated data (NULL if unused).
external_aad_len External AAD length.
out_plaintext [out] Output buffer for decrypted plaintext.
out_plaintext_size Output buffer capacity.
out_plaintext_len [out] Number of plaintext bytes written.
parsed_out [out] Optional parsed message details (may be NULL).

Returns:

SYN_Status SYN_OK if decrypted and authenticated, error code otherwise.

function syn_cose_key_decode¶

Decode a CBOR-encoded COSE_Key map into a SYN_COSE_Key structure.

SYN_Status syn_cose_key_decode (
    const uint8_t * buf,
    size_t buf_len,
    SYN_COSE_Key * key_out
)

Parameters:

buf Input CBOR buffer.
buf_len Length of CBOR buffer.
key_out [out] Decoded key descriptor.

Returns:

SYN_Status SYN_OK on success, error code otherwise.

function syn_cose_key_encode¶

Encode a COSE_Key structure into CBOR format.

SYN_Status syn_cose_key_encode (
    const SYN_COSE_Key * key,
    uint8_t * out_buf,
    size_t out_buf_size,
    size_t * out_len
)

Parameters:

key Pointer to populated COSE_Key descriptor.
out_buf [out] Output buffer for encoded CBOR map.
out_buf_size Capacity of output buffer.
out_len [out] Number of bytes written.

Returns:

SYN_Status SYN_OK on success, error code otherwise.

function syn_cose_mac0_create¶

Create a COSE_Mac0 (Tag 17) message using HMAC-SHA256.

SYN_Status syn_cose_mac0_create (
    SYN_COSE_Algorithm alg,
    const uint8_t * key,
    size_t key_len,
    const uint8_t * kid,
    size_t kid_len,
    const uint8_t * payload,
    size_t payload_len,
    const uint8_t * external_aad,
    size_t external_aad_len,
    uint8_t * out_buf,
    size_t out_buf_size,
    size_t * out_len
)

Parameters:

alg MAC algorithm (SYN_COSE_ALGO_HMAC_256_256 or SYN_COSE_ALGO_HMAC_256_64).
key MAC key.
key_len Key length in bytes.
kid Optional key identifier (NULL if unused).
kid_len Key identifier length.
payload Message payload to authenticate.
payload_len Payload length.
external_aad Optional external associated data (NULL if unused).
external_aad_len External AAD length.
out_buf [out] Output buffer for encoded COSE_Mac0 message.
out_buf_size Capacity of output buffer.
out_len [out] Number of bytes written to output buffer.

Returns:

SYN_Status SYN_OK on success, error code otherwise.

function syn_cose_mac0_verify¶

Verify a COSE_Mac0 message using HMAC-SHA256.

SYN_Status syn_cose_mac0_verify (
    const uint8_t * msg,
    size_t msg_len,
    const uint8_t * key,
    size_t key_len,
    const uint8_t * external_aad,
    size_t external_aad_len,
    SYN_COSE_Mac0Message * parsed_out
)

Parameters:

msg Raw COSE_Mac0 CBOR encoded message.
msg_len Message length.
key MAC key.
key_len Key length in bytes.
external_aad Optional external associated data (NULL if unused).
external_aad_len External AAD length.
parsed_out [out] Optional parsed message details (may be NULL).

Returns:

SYN_Status SYN_OK if authentication tag is valid, error code otherwise.

function syn_cose_sign1_create¶

Create a COSE_Sign1 (Tag 18) message signed with EdDSA (Ed25519) or ES256 (P-256).

SYN_Status syn_cose_sign1_create (
    SYN_COSE_Algorithm alg,
    const uint8_t * secret_key,
    const uint8_t * public_key,
    const uint8_t * kid,
    size_t kid_len,
    const uint8_t * payload,
    size_t payload_len,
    const uint8_t * external_aad,
    size_t external_aad_len,
    uint8_t * out_buf,
    size_t out_buf_size,
    size_t * out_len
)

Parameters:

alg Signature algorithm (SYN_COSE_ALGO_EDDSA or SYN_COSE_ALGO_ES256).
secret_key Secret key (32 bytes for Ed25519 / P-256 scalar).
public_key Public key (32 bytes for Ed25519, 64/65 bytes for P-256).
kid Optional key identifier (NULL if unused).
kid_len Key identifier length.
payload Message payload to sign.
payload_len Payload length.
external_aad Optional external associated data (NULL if unused).
external_aad_len External AAD length.
out_buf [out] Output buffer for encoded COSE_Sign1 message.
out_buf_size Capacity of output buffer.
out_len [out] Number of bytes written to output buffer.

Returns:

SYN_Status SYN_OK on success, error code otherwise.

function syn_cose_sign1_verify¶

Parse and verify a COSE_Sign1 message using the signer's public key.

SYN_Status syn_cose_sign1_verify (
    const uint8_t * msg,
    size_t msg_len,
    const uint8_t * public_key,
    size_t public_key_len,
    const uint8_t * external_aad,
    size_t external_aad_len,
    SYN_COSE_Sign1Message * parsed_out
)

Parameters:

msg Raw COSE_Sign1 CBOR encoded message.
msg_len Message length.
public_key Public key of the signer.
public_key_len Public key length (32 for Ed25519, 64/65 for P-256).
external_aad Optional external associated data (NULL if unused).
external_aad_len External AAD length.
parsed_out [out] Optional parsed message details (may be NULL).

Returns:

SYN_Status SYN_OK if verified and valid, error code otherwise.

The documentation for this class was generated from the following file src/syntropic/proto/syn_cose.c