Secure Key Handler¶

typedef struct cardano_secure_key_handler_t cardano_secure_key_handler_t¶

Opaque type definition for the secure key handler.

cardano_secure_key_handler_t is an opaque structure representing a secure key handler. This handler abstracts the management of cryptographic key operations for both BIP32 (HD) and Ed25519 key types, ensuring that sensitive key material is managed securely. The internal details of this structure are hidden from users of the API, who interact with it through the provided API functions.

cardano_error_t cardano_secure_key_handler_new(cardano_secure_key_handler_impl_t impl, cardano_secure_key_handler_t **secure_key_handler)¶

Creates a new cardano_secure_key_handler_t object using the provided implementation.

This function initializes a new cardano_secure_key_handler_t object by wrapping the given cardano_secure_key_handler_impl_t implementation. The newly created secure_key_handler object manages the lifecycle of the underlying implementation and provides an interface for interacting with cryptographic keys securely.

Usage Example:

// Assume 'impl' is a valid cardano_secure_key_handler_impl_t initialized elsewhere.
cardano_secure_key_handler_t* secure_key_handler = NULL;
cardano_error_t result = cardano_secure_key_handler_new(impl, &secure_key_handler);

if (result == CARDANO_SUCCESS)
{
  // Use the secure_key_handler
}
else
{
  printf("Error: %s\n", cardano_error_to_string(result));
}

// When done with the secure_key_handler
cardano_secure_key_handler_unref(&secure_key_handler);

Note

After successfully creating a cardano_secure_key_handler_t object, you are responsible for managing its lifecycle. Ensure that you call cardano_secure_key_handler_unref when the secure_key_handler is no longer needed to release resources and prevent memory leaks.

Parameters:¶

cardano_secure_key_handler_impl_t impl¶: [in] The secure_key_handler implementation containing function pointers and context.
cardano_secure_key_handler_t **secure_key_handler¶: [out] A pointer to store the address of the newly created secure_key_handler object. This should be a valid pointer to a cardano_secure_key_handler_t* variable.

Returns:¶

A cardano_error_t indicating success or failure of the operation.

const char *cardano_secure_key_handler_get_name(const cardano_secure_key_handler_t *secure_key_handler)¶

Retrieves the name of the secure_key_handler implementation.

This function returns a constant string representing the name of the secure_key_handler implementation. The name can be used for logging, debugging, or informational purposes to identify which secure_key_handler implementation is being used.

Usage Example:

const char* secure_key_handler_name = cardano_secure_key_handler_get_name(secure_key_handler);

if (secure_key_handler_name)
{
  printf("Using secure_key_handler: %s\n", secure_key_handler_name);
}
else
{
  printf("Failed to retrieve secure_key_handler name.\n");
}

Note

The returned string remains valid as long as the cardano_secure_key_handler_t object is valid. Do not attempt to modify or free the returned string.

Parameters:¶

const cardano_secure_key_handler_t *secure_key_handler¶: [in] Pointer to the cardano_secure_key_handler_t object.

Returns:¶

A constant character pointer to the secure_key_handler’s name string. The returned string is owned by the secure_key_handler and must not be modified or freed by the caller. If the secure_key_handler is NULL or invalid, the function may return NULL.

cardano_error_t cardano_secure_key_handler_bip32_sign_transaction(cardano_secure_key_handler_t *secure_key_handler, cardano_transaction_t *tx, const cardano_derivation_path_t *derivation_paths, size_t num_paths, cardano_vkey_witness_set_t **vkey_witness_set)¶

Signs a transaction using BIP32 Hierarchical Deterministic (HD) keys.

This function uses the cardano_secure_key_handler_t to securely manage the cryptographic key operations needed to sign a transaction using BIP32 (HD) keys. It derives the necessary private keys based on the provided derivation_paths and signs the transaction tx, generating a set of verification key witnesses (vkey_witness_set).

Note

The caller is responsible for managing and releasing the vkey_witness_set to avoid memory leaks.

Parameters:¶

cardano_secure_key_handler_t *secure_key_handler¶: [in] A pointer to the secure key handler managing the cryptographic key operations.
cardano_transaction_t *tx¶: [in] The transaction object to be signed.
const cardano_derivation_path_t *derivation_paths¶: [in] An array of BIP32 derivation paths used to derive the private keys for signing the transaction.
size_t num_paths¶: [in] The number of derivation paths provided in the derivation_paths array.
cardano_vkey_witness_set_t **vkey_witness_set¶: [out] A pointer to the verification key witness set that will be populated with the generated signatures. This set will contain the signatures and associated verification keys required for the transaction.

Returns:¶

cardano_error_t indicating success or the type of error encountered during signing.

cardano_error_t cardano_secure_key_handler_bip32_get_extended_account_public_key(cardano_secure_key_handler_t *secure_key_handler, cardano_account_derivation_path_t derivation_path, cardano_bip32_public_key_t **bip32_public_key)¶

Retrieves the extended BIP32 account public key for a given derivation path.

This function securely derives and retrieves the extended BIP32 account public key for the cardano_secure_key_handler_t. The extended BIP32 public key includes both the Ed25519 public key and chain code, enabling further key derivations within the BIP32 standard.

Note

The caller is responsible for managing the lifecycle of the bip32_public_key object, ensuring it is properly released to avoid memory leaks.

Parameters:¶

cardano_secure_key_handler_t *secure_key_handler¶: [in] A pointer to the secure key handler managing the cryptographic key operations.
cardano_account_derivation_path_t derivation_path¶: [in] The BIP32 derivation path used to derive the extended account public key.
cardano_bip32_public_key_t **bip32_public_key¶: [out] A pointer to the extended BIP32 public key that will be retrieved and returned. The caller must manage the lifecycle of the returned bip32_public_key and release it when done.

Returns:¶

cardano_error_t indicating success or the type of error encountered during key retrieval.

cardano_error_t cardano_secure_key_handler_ed25519_sign_transaction(cardano_secure_key_handler_t *secure_key_handler, cardano_transaction_t *tx, cardano_vkey_witness_set_t **vkey_witness_set)¶

Signs a transaction using Ed25519 keys.

This function securely signs the provided tx (transaction) using the Ed25519 keys managed by the cardano_secure_key_handler_t. The resulting witness set, containing the verification keys and signatures, is returned in the vkey_witness_set.

Note

This function does not support BIP32 hierarchical deterministic keys. It is intended for use with Ed25519 keys only.

Note

The caller is responsible for managing the lifecycle of the vkey_witness_set to ensure proper memory management.

Parameters:¶

cardano_secure_key_handler_t *secure_key_handler¶: [in] A pointer to the secure key handler managing the Ed25519 cryptographic operations.
cardano_transaction_t *tx¶: [in] The transaction object to be signed.
cardano_vkey_witness_set_t **vkey_witness_set¶: [out] A pointer to the verification key witness set that will be populated with the generated signatures. The caller must manage the lifecycle of the vkey_witness_set to avoid memory leaks.

Returns:¶

cardano_error_t indicating success or the type of error encountered during signing.

cardano_error_t cardano_secure_key_handler_ed25519_get_public_key(cardano_secure_key_handler_t *secure_key_handler, cardano_ed25519_public_key_t **public_key)¶

Retrieves the public key associated with the Ed25519 key.

This function securely retrieves the Ed25519 public key from the cardano_secure_key_handler_t. The resulting public key is returned in the public_key parameter.

Note

This function only handles Ed25519 public keys and does not support BIP32 keys.

Note

The caller is responsible for managing the lifecycle of the public_key to ensure proper memory management.

Parameters:¶

cardano_secure_key_handler_t *secure_key_handler¶: [in] A pointer to the secure key handler managing the Ed25519 cryptographic operations.
cardano_ed25519_public_key_t **public_key¶: [out] A pointer to the location where the Ed25519 public key will be stored. The caller is responsible for managing the lifecycle of this object and must release it appropriately to avoid memory leaks.

Returns:¶

cardano_error_t indicating success or the type of error encountered during the retrieval.

void cardano_secure_key_handler_unref(cardano_secure_key_handler_t **secure_key_handler)¶

Decrements the reference count of a cardano_secure_key_handler_t object.

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

Usage Example:

cardano_secure_key_handler_t* secure_key_handler = cardano_secure_key_handler_new(major, minor);

// Perform operations with the secure_key_handler...

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

Note

After calling cardano_secure_key_handler_unref, the pointer to the cardano_secure_key_handler_t object will be set to NULL to prevent its reuse.

Parameters:¶

cardano_secure_key_handler_t **secure_key_handler¶: [inout] A pointer to the pointer of the secure_key_handler 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_secure_key_handler_ref(cardano_secure_key_handler_t *secure_key_handler)¶

Increases the reference count of the cardano_secure_key_handler_t object.

This function is used to manually increment the reference count of an cardano_secure_key_handler_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_secure_key_handler_unref.

Usage Example:

// Assuming secure_key_handler is a previously created secure_key_handler object

cardano_secure_key_handler_ref(secure_key_handler);

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

Note

Always ensure that for every call to cardano_secure_key_handler_ref there is a corresponding call to cardano_secure_key_handler_unref to prevent memory leaks.

Parameters:¶

cardano_secure_key_handler_t *secure_key_handler¶: A pointer to the cardano_secure_key_handler_t object whose reference count is to be incremented.

cardano_error_t cardano_secure_key_handler_serialize(cardano_secure_key_handler_t *secure_key_handler, cardano_buffer_t **serialized_data)¶

Serializes the state of a secure key handler.

The cardano_secure_key_handler_serialize function serializes the internal state or key material associated with a secure key handler into a buffer. This allows the key handler to be stored or transferred in a secure, serialized format.

This function is expected to:

Serialize the current state of the secure key handler into the provided serialized_data buffer.

Note

The caller is responsible for releasing the serialized buffer after use to avoid memory leaks.

Parameters:¶

cardano_secure_key_handler_t *secure_key_handler¶: A pointer to the secure key handler that manages cryptographic operations.
cardano_buffer_t **serialized_data¶: A pointer to the buffer that will be populated with the serialized state of the key handler. This buffer must be managed and freed by the caller to prevent memory leaks.

Returns:¶

cardano_error_t indicating success or the type of error encountered during serialization.

size_t cardano_secure_key_handler_refcount(const cardano_secure_key_handler_t *secure_key_handler)¶

Retrieves the current reference count of the cardano_secure_key_handler_t object.

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

Usage Example:

// Assuming secure_key_handler is a previously created secure_key_handler object

size_t ref_count = cardano_secure_key_handler_refcount(secure_key_handler);

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_secure_key_handler_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_secure_key_handler_t *secure_key_handler¶: A pointer to the cardano_secure_key_handler_t object whose reference count is queried. The object must not be NULL.

Returns:¶

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

void cardano_secure_key_handler_set_last_error(cardano_secure_key_handler_t *secure_key_handler, const char *message)¶

Sets the last error message for a given cardano_secure_key_handler_t object.

Records an error message in the secure_key_handler’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_secure_key_handler_t *secure_key_handler¶: [in] A pointer to the cardano_secure_key_handler_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 secure_key_handler’s last_error is set to an empty string, indicating no error.

const char *cardano_secure_key_handler_get_last_error(const cardano_secure_key_handler_t *secure_key_handler)¶

Retrieves the last error message recorded for a specific secure_key_handler.

This function returns a pointer to the null-terminated string containing the last error message set by cardano_secure_key_handler_set_last_error for the given secure_key_handler. 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_secure_key_handler_set_last_error for the same secure_key_handler, or until the secure_key_handler is deallocated.

Parameters:¶

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

Returns:¶

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