Function esp_idf_svc::sys::psa_copy_key

pub unsafe extern "C" fn psa_copy_key(
    source_key: u32,
    attributes: *const psa_key_attributes_s,
    target_key: *mut u32,
) -> i32

Make a copy of a key.

Copy key material from one location to another.

This function is primarily useful to copy a key from one location to another, since it populates a key using the material from another key which may have a different lifetime.

This function may be used to share a key with a different party, subject to implementation-defined restrictions on key sharing.

The policy on the source key must have the usage flag #PSA_KEY_USAGE_COPY set. This flag is sufficient to permit the copy if the key has the lifetime #PSA_KEY_LIFETIME_VOLATILE or #PSA_KEY_LIFETIME_PERSISTENT. Some secure elements do not provide a way to copy a key without making it extractable from the secure element. If a key is located in such a secure element, then the key must have both usage flags #PSA_KEY_USAGE_COPY and #PSA_KEY_USAGE_EXPORT in order to make a copy of the key outside the secure element.

The resulting key may only be used in a way that conforms to both the policy of the original key and the policy specified in the \p attributes parameter:

• The usage flags on the resulting key are the bitwise-and of the usage flags on the source policy and the usage flags in \p attributes.
• If both allow the same algorithm or wildcard-based algorithm policy, the resulting key has the same algorithm policy.
• If either of the policies allows an algorithm and the other policy allows a wildcard-based algorithm policy that includes this algorithm, the resulting key allows the same algorithm.
• If the policies do not allow any algorithm in common, this function fails with the status #PSA_ERROR_INVALID_ARGUMENT.

The effect of this function on implementation-defined attributes is implementation-defined.

\param source_key The key to copy. It must allow the usage #PSA_KEY_USAGE_COPY. If a private or secret key is being copied outside of a secure element it must also allow #PSA_KEY_USAGE_EXPORT. \param[in] attributes The attributes for the new key. They are used as follows: - The key type and size may be 0. If either is nonzero, it must match the corresponding attribute of the source key. - The key location (the lifetime and, for persistent keys, the key identifier) is used directly. - The policy constraints (usage flags and algorithm policy) are combined from the source key and \p attributes so that both sets of restrictions apply, as described in the documentation of this function. \param[out] target_key On success, an identifier for the newly created key. For persistent keys, this is the key identifier defined in \p attributes. \c 0 on failure.

\retval #PSA_SUCCESS \emptydescription \retval #PSA_ERROR_INVALID_HANDLE \p source_key is invalid. \retval #PSA_ERROR_ALREADY_EXISTS This is an attempt to create a persistent key, and there is already a persistent key with the given identifier. \retval #PSA_ERROR_INVALID_ARGUMENT The lifetime or identifier in \p attributes are invalid, or the policy constraints on the source and specified in \p attributes are incompatible, or \p attributes specifies a key type or key size which does not match the attributes of the source key. \retval #PSA_ERROR_NOT_PERMITTED The source key does not have the #PSA_KEY_USAGE_COPY usage flag, or the source key is not exportable and its lifetime does not allow copying it to the target’s lifetime. \retval #PSA_ERROR_INSUFFICIENT_MEMORY \emptydescription \retval #PSA_ERROR_INSUFFICIENT_STORAGE \emptydescription \retval #PSA_ERROR_COMMUNICATION_FAILURE \emptydescription \retval #PSA_ERROR_HARDWARE_FAILURE \emptydescription \retval #PSA_ERROR_DATA_INVALID \emptydescription \retval #PSA_ERROR_DATA_CORRUPT \emptydescription \retval #PSA_ERROR_STORAGE_FAILURE \emptydescription \retval #PSA_ERROR_CORRUPTION_DETECTED \emptydescription \retval #PSA_ERROR_BAD_STATE The library has not been previously initialized by psa_crypto_init(). It is implementation-dependent whether a failure to initialize results in this error code.