VKey Witness¶

typedef struct cardano_vkey_witness_t cardano_vkey_witness_t¶: vkey Witness (Verification Key Witness) is a component of a transaction that provides cryptographic proof that proves that the creator of the transaction has access to the private keys controlling the UTxOs being spent.

cardano_error_t cardano_vkey_witness_new(cardano_ed25519_public_key_t *vkey, cardano_ed25519_signature_t *signature, cardano_vkey_witness_t **vkey_witness)¶

Creates and initializes a new instance of a Vkey Witness.

This function allocates and initializes a new instance of a cardano_vkey_witness_t object.

Usage Example:

cardano_ed25519_public_key_t* vkey = ...; // Assume vkey is already initialized
cardano_ed25519_signature_t* signature = ...; // Assume signature is already initialized
cardano_vkey_witness_t* vkey_witness = NULL;

cardano_error_t result = cardano_vkey_witness_new(vkey, signature, &vkey_witness);

if (result == CARDANO_SUCCESS)
{
  // Use the vkey_witness
  // Once done, ensure to clean up and release the vkey_witness
  cardano_vkey_witness_unref(&vkey_witness);
}
else
{
  printf("Failed to create the vkey witness.\n");
}

// Cleanup the other inputs
cardano_ed25519_public_key_unref(&vkey);
cardano_ed25519_signature_unref(&signature);

Parameters:¶

cardano_ed25519_public_key_t *vkey¶: [in] A pointer to an initialized cardano_ed25519_public_key_t object representing the public verification key (VKey). This key is used to verify the cryptographic signature.
cardano_ed25519_signature_t *signature¶: [in] A pointer to an initialized cardano_ed25519_signature_t object containing the cryptographic signature. This signature is produced by signing the hash of the transaction body with the corresponding private key. The VKey is used to verify that the signature is valid and was made by the owner of the corresponding private key.
cardano_vkey_witness_t **vkey_witness¶: [out] On successful initialization, this will point to a newly created cardano_vkey_witness_t object. This object represents a “strong reference” to the vkey witness, meaning that it is fully initialized and ready for use. The caller is responsible for managing the lifecycle of this object. Specifically, once the vkey witness is no longer needed, the caller must release it by calling cardano_vkey_witness_unref.

Returns:¶

cardano_error_t indicating the outcome of the operation. Returns CARDANO_SUCCESS if the vkey witness was successfully created, or an appropriate error code indicating the failure reason.

cardano_error_t cardano_vkey_witness_from_cbor(cardano_cbor_reader_t *reader, cardano_vkey_witness_t **vkey_witness)¶

Creates a cardano_vkey_witness_t from a CBOR reader.

This function parses CBOR data using a provided cardano_cbor_reader_t and constructs a cardano_vkey_witness_t object. It assumes that the CBOR reader is set up correctly and that the CBOR data corresponds to the structure expected for a vkey_witness.

Usage Example:

cardano_cbor_reader_t* reader = cardano_cbor_reader_new(cbor_data, data_size);
cardano_vkey_witness_t* vkey_witness = NULL;

cardano_error_t result = cardano_vkey_witness_from_cbor(reader, &vkey_witness);

if (result == CARDANO_SUCCESS)
{
  // Use the vkey_witness

  // Once done, ensure to clean up and release the vkey_witness
  cardano_vkey_witness_unref(&vkey_witness);
}
else
{
  const char* error = cardano_cbor_reader_get_last_error(reader);
  printf("Failed to decode vkey_witness: %s\n", error);
}

cardano_cbor_reader_unref(&reader); // Cleanup the CBOR reader

Note

If the function fails, the last error can be retrieved by calling cardano_cbor_reader_get_last_error with the reader. The caller is responsible for freeing the created cardano_vkey_witness_t object by calling cardano_vkey_witness_unref when it is no longer needed.

Parameters:¶

cardano_cbor_reader_t *reader¶: [in] A pointer to an initialized cardano_cbor_reader_t that is ready to read the CBOR-encoded data.
cardano_vkey_witness_t **vkey_witness¶: [out] A pointer to a pointer of cardano_vkey_witness_t that will be set to the address of the newly created vkey_witness object upon successful decoding.

Returns:¶

A cardano_error_t value indicating the outcome of the operation. Returns CARDANO_SUCCESS if the vkey witness were successfully created, or an appropriate error code if an error occurred.

cardano_error_t cardano_vkey_witness_to_cbor(const cardano_vkey_witness_t *vkey_witness, cardano_cbor_writer_t *writer)¶

Serializes vkey witness into CBOR format using a CBOR writer.

This function serializes the given cardano_vkey_witness_t object using a cardano_cbor_writer_t.

Usage Example:

cardano_vkey_witness_t* vkey_witness = ...;
cardano_cbor_writer_t* writer = cardano_cbor_writer_new();

if (writer)
{
  cardano_error_t result = cardano_vkey_witness_to_cbor(vkey_witness, writer);

  if (result == CARDANO_SUCCESS)
  {
    // Use the writer's buffer containing the serialized data
  }
  else
  {
    const char* error_message = cardano_cbor_writer_get_last_error(writer);
    printf("Serialization failed: %s\n", error_message);
  }

  cardano_cbor_writer_unref(&writer);
}

cardano_vkey_witness_unref(&vkey_witness);

Parameters:¶

const cardano_vkey_witness_t *vkey_witness¶: [in] A constant pointer to the cardano_vkey_witness_t object that is to be serialized.
cardano_cbor_writer_t *writer¶: [out] A pointer to a cardano_cbor_writer_t where the CBOR serialized data will be written. The writer must already be initialized and ready to accept the data.

Returns:¶

Returns CARDANO_SUCCESS if the serialization is successful. If the vkey_witness or writer is NULL, returns CARDANO_ERROR_POINTER_IS_NULL.

cardano_error_t cardano_vkey_witness_to_cip116_json(const cardano_vkey_witness_t *witness, cardano_json_writer_t *writer)¶

Serializes a VKey witness to CIP-116 JSON.

The function writes the full JSON object, including the surrounding braces. Keys are written in the order: “vkey”, “signature”.

Parameters:¶

const cardano_vkey_witness_t *witness¶: [in] Pointer to a valid cardano_vkey_witness_t.
cardano_json_writer_t *writer¶: [in] Pointer to a valid cardano_json_writer_t.

Returns:¶

CARDANO_SUCCESS On success. CARDANO_ERROR_POINTER_IS_NULL If witness or writer is NULL. CARDANO_ERROR_MEMORY_ALLOCATION_FAILED If memory allocation fails. Other Any error propagated from nested writers.

bool cardano_vkey_witness_has_public_key(const cardano_vkey_witness_t *vkey_witness, const cardano_ed25519_public_key_t *vkey)¶

Checks if a vkey_witness contains a specific public key.

This function checks if the provided cardano_vkey_witness_t object contains the specified Ed25519 public key. It is useful for determining if a particular witness corresponds to a given public key.

Usage Example:

cardano_vkey_witness_t* vkey_witness = { ... };
cardano_ed25519_public_key_t* public_key = { ... };

// Check if the vkey_witness contains the specified public key
bool has_key = cardano_vkey_witness_has_public_key(vkey_witness, public_key);

if (has_key)
{
  // The vkey_witness contains the public key
}
else
{
  // The public key is not present in the vkey_witness
}

Note

This function only compares the public key, and not the associated signature or any other witness data.

Parameters:¶

const cardano_vkey_witness_t *vkey_witness¶: [in] A constant pointer to the cardano_vkey_witness_t object to be checked.
const cardano_ed25519_public_key_t *vkey¶: [in] A constant pointer to the cardano_ed25519_public_key_t object representing the public key to search for.

Returns:¶

true if the public key is found in the vkey_witness; otherwise, false.

cardano_ed25519_public_key_t *cardano_vkey_witness_get_vkey(cardano_vkey_witness_t *vkey_witness)¶

Retrieves the verification key (VKey) from a Vkey Witness.

This function returns the cardano_ed25519_public_key_t object representing the public verification key (VKey) associated with a cardano_vkey_witness_t object. The VKey is used to verify the cryptographic signature provided in the vkey witness.

Usage Example:

cardano_vkey_witness_t* vkey_witness = ...; // Assume vkey_witness is initialized
cardano_ed25519_public_key_t* vkey = cardano_vkey_witness_get_vkey(vkey_witness);

if (vkey != NULL)
{
  // Use the verification key
  // Once done, ensure to clean up and release the vkey
  cardano_ed25519_public_key_unref(&vkey);
}
else
{
  printf("Failed to retrieve the verification key.\n");
}

Parameters:¶

cardano_vkey_witness_t *vkey_witness¶: [in] A pointer to an initialized cardano_vkey_witness_t object from which the verification key will be retrieved.

Returns:¶

A pointer to the cardano_ed25519_public_key_t object representing the verification key. The caller is responsible for managing the lifecycle of the returned VKey. Specifically, the caller must release it by calling cardano_ed25519_public_key_unref when it is no longer needed. If vkey_witness is NULL, the function will return NULL.

cardano_error_t cardano_vkey_witness_set_vkey(cardano_vkey_witness_t *vkey_witness, cardano_ed25519_public_key_t *vkey)¶

Sets the verification key (VKey) for a Vkey Witness.

This function assigns a new cardano_ed25519_public_key_t object as the verification key (VKey) for the given cardano_vkey_witness_t object. The VKey is the public key that is used to verify the cryptographic signature in the vkey witness.

Usage Example:

cardano_vkey_witness_t* vkey_witness = ...; // Assume vkey_witness is initialized
cardano_ed25519_public_key_t* vkey = ...; // Assume vkey is initialized

cardano_error_t result = cardano_vkey_witness_set_vkey(vkey_witness, vkey);

if (result == CARDANO_SUCCESS)
{
  printf("VKey set successfully.\n");
}
else
{
  printf("Failed to set the VKey.\n");
}

// Cleanup resources for the VKey as it is still owned by the caller
cardano_ed25519_public_key_unref(&vkey);

Note

The function does not take ownership of the vkey, meaning the caller is still responsible for freeing the cardano_ed25519_public_key_t object when it is no longer needed.

Parameters:¶

cardano_vkey_witness_t *vkey_witness¶: [inout] A pointer to an initialized cardano_vkey_witness_t object to which the verification key will be assigned.
cardano_ed25519_public_key_t *vkey¶: [in] A pointer to an initialized cardano_ed25519_public_key_t object representing the new verification key. The caller retains ownership of this object and must ensure its lifecycle is properly managed.

Returns:¶

cardano_error_t indicating the outcome of the operation. Returns CARDANO_SUCCESS if the verification key was successfully set, or an appropriate error code if an error occurred, such as CARDANO_ERROR_POINTER_IS_NULL if either vkey_witness or vkey is NULL.

cardano_ed25519_signature_t *cardano_vkey_witness_get_signature(cardano_vkey_witness_t *vkey_witness)¶

Retrieves the cryptographic signature from a Vkey Witness.

This function retrieves the cardano_ed25519_signature_t object from a given cardano_vkey_witness_t object. The signature is produced by signing the hash of the transaction body using the corresponding private key (SKey), and it can be verified using the associated public key (VKey).

Usage Example:

cardano_vkey_witness_t* vkey_witness = ...; // Assume vkey_witness is initialized
cardano_ed25519_signature_t* signature = cardano_vkey_witness_get_signature(vkey_witness);

if (signature != NULL)
{
  // Process the signature
  cardano_ed25519_signature_unref(&signature); // Ensure to clean up the signature
}
else
{
  printf("Failed to retrieve the signature.\n");
}

Parameters:¶

cardano_vkey_witness_t *vkey_witness¶: [in] A pointer to an initialized cardano_vkey_witness_t object from which the signature will be retrieved.

Returns:¶

A pointer to the cardano_ed25519_signature_t object representing the signature. The returned signature is a new reference, and the caller is responsible for managing its lifecycle. Specifically, the caller must release it using cardano_ed25519_signature_unref when it is no longer needed. If vkey_witness is NULL, this function will return NULL.

cardano_error_t cardano_vkey_witness_set_signature(cardano_vkey_witness_t *vkey_witness, cardano_ed25519_signature_t *signature)¶

Sets the cryptographic signature for a Vkey Witness.

This function assigns a new cardano_ed25519_signature_t object to a given cardano_vkey_witness_t object. The signature is produced by signing the hash of the transaction body using the corresponding private key (SKey), and it can be verified using the associated public key (VKey).

Usage Example:

cardano_vkey_witness_t* vkey_witness = ...; // Assume vkey_witness is initialized
cardano_ed25519_signature_t* signature = ...; // Assume signature is initialized

cardano_error_t result = cardano_vkey_witness_set_signature(vkey_witness, signature);
if (result == CARDANO_SUCCESS)
{
  printf("Signature successfully set.\n");
}
else
{
  printf("Failed to set the signature.\n");
}

// Clean up
cardano_ed25519_signature_unref(&signature); // Caller still owns their reference to the signature

Note

This function increases the reference count of the signature object; therefore, the caller retains ownership of their reference and must release their copy when it is no longer needed using cardano_ed25519_signature_unref.

Parameters:¶

cardano_vkey_witness_t *vkey_witness¶: [inout] A pointer to an initialized cardano_vkey_witness_t object to which the signature will be assigned.
cardano_ed25519_signature_t *signature¶: [in] A pointer to an initialized cardano_ed25519_signature_t object representing the signature. This parameter must not be NULL.

Returns:¶

cardano_error_t indicating the outcome of the operation. Returns CARDANO_SUCCESS if the signature was successfully set. Returns CARDANO_ERROR_POINTER_IS_NULL if either vkey_witness or signature is NULL.

void cardano_vkey_witness_unref(cardano_vkey_witness_t **vkey_witness)¶

Decrements the reference count of a cardano_vkey_witness_t object.

This function is responsible for managing the lifecycle of a cardano_vkey_witness_t object by decreasing its reference count. When the reference count reaches zero, the vkey_witness is finalized; its associated resources are released, and its memory is deallocated.

Usage Example:

cardano_vkey_witness_t* vkey_witness = cardano_vkey_witness_new(major, minor);

// Perform operations with the vkey_witness...

cardano_vkey_witness_unref(&vkey_witness);
// At this point, vkey_witness is NULL and cannot be used.

Note

After calling cardano_vkey_witness_unref, the pointer to the cardano_vkey_witness_t object will be set to NULL to prevent its reuse.

Parameters:¶

cardano_vkey_witness_t **vkey_witness¶: [inout] A pointer to the pointer of the vkey_witness object. This double indirection allows the function to set the caller’s pointer to NULL, avoiding dangling pointer issues after the object has been freed.

void cardano_vkey_witness_ref(cardano_vkey_witness_t *vkey_witness)¶

Increases the reference count of the cardano_vkey_witness_t object.

This function is used to manually increment the reference count of an cardano_vkey_witness_t object, indicating that another part of the code has taken ownership of it. This ensures the object remains allocated and valid until all owners have released their reference by calling cardano_vkey_witness_unref.

Usage Example:

// Assuming vkey_witness is a previously created vkey_witness object

cardano_vkey_witness_ref(vkey_witness);

// Now vkey_witness can be safely used elsewhere without worrying about premature deallocation

Note

Always ensure that for every call to cardano_vkey_witness_ref there is a corresponding call to cardano_vkey_witness_unref to prevent memory leaks.

Parameters:¶

cardano_vkey_witness_t *vkey_witness¶: A pointer to the cardano_vkey_witness_t object whose reference count is to be incremented.

size_t cardano_vkey_witness_refcount(const cardano_vkey_witness_t *vkey_witness)¶

Retrieves the current reference count of the cardano_vkey_witness_t object.

This function returns the number of active references to an cardano_vkey_witness_t object. It’s useful for debugging purposes or managing the lifecycle of the object in complex scenarios.

Usage Example:

// Assuming vkey_witness is a previously created vkey_witness object

size_t ref_count = cardano_vkey_witness_refcount(vkey_witness);

printf("Reference count: %zu\n", ref_count);

Warning

This function does not account for transitive references. A transitive reference occurs when an object holds a reference to another object, rather than directly to the cardano_vkey_witness_t. As such, the reported count may not fully represent the total number of conceptual references in cases where such transitive relationships exist.

Parameters:¶

const cardano_vkey_witness_t *vkey_witness¶: A pointer to the cardano_vkey_witness_t object whose reference count is queried. The object must not be NULL.

Returns:¶

The number of active references to the specified cardano_vkey_witness_t object. If the object is properly managed (i.e., every cardano_vkey_witness_ref call is matched with a cardano_vkey_witness_unref call), this count should reach zero right before the object is deallocated.

void cardano_vkey_witness_set_last_error(cardano_vkey_witness_t *vkey_witness, const char *message)¶

Sets the last error message for a given cardano_vkey_witness_t object.

Records an error message in the vkey_witness’s last_error buffer, overwriting any existing message. This is useful for storing descriptive error information that can be later retrieved. The message is truncated if it exceeds the buffer’s capacity.

Note

The error message is limited to 1023 characters, including the null terminator, due to the fixed size of the last_error buffer.

Parameters:¶

cardano_vkey_witness_t *vkey_witness¶: [in] A pointer to the cardano_vkey_witness_t instance whose last error message is to be set. If NULL, the function does nothing.
const char *message¶: [in] A null-terminated string containing the error message. If NULL, the vkey_witness’s last_error is set to an empty string, indicating no error.

const char *cardano_vkey_witness_get_last_error(const cardano_vkey_witness_t *vkey_witness)¶

Retrieves the last error message recorded for a specific vkey_witness.

This function returns a pointer to the null-terminated string containing the last error message set by cardano_vkey_witness_set_last_error for the given vkey_witness. If no error message has been set, or if the last_error buffer was explicitly cleared, an empty string is returned, indicating no error.

Note

The returned string points to internal storage within the object and must not be modified by the caller. The string remains valid until the next call to cardano_vkey_witness_set_last_error for the same vkey_witness, or until the vkey_witness is deallocated.

Parameters:¶

const cardano_vkey_witness_t *vkey_witness¶: [in] A pointer to the cardano_vkey_witness_t instance whose last error message is to be retrieved. If the vkey_witness is NULL, the function returns a generic error message indicating the null vkey_witness.

Returns:¶

A pointer to a null-terminated string containing the last error message for the specified vkey_witness. If the vkey_witness is NULL, “Object is NULL.” is returned to indicate the error.