diff --git a/include/psa/crypto.h b/include/psa/crypto.h
index 94060c1..9780681 100755
--- a/include/psa/crypto.h
+++ b/include/psa/crypto.h
@@ -50,212 +50,232 @@
  *
  * Zero indicates success, anything else indicates an error.
  */
-typedef enum {
-    /** The action was completed successfully. */
-    PSA_SUCCESS = 0,
-    /** The requested operation or a parameter is not supported
-     * by this implementation.
-     *
-     * Implementations should return this error code when an enumeration
-     * parameter such as a key type, algorithm, etc. is not recognized.
-     * If a combination of parameters is recognized and identified as
-     * not valid, return #PSA_ERROR_INVALID_ARGUMENT instead. */
-    PSA_ERROR_NOT_SUPPORTED,
-    /** The requested action is denied by a policy.
-     *
-     * Implementations should return this error code when the parameters
-     * are recognized as valid and supported, and a policy explicitly
-     * denies the requested operation.
-     *
-     * If a subset of the parameters of a function call identify a
-     * forbidden operation, and another subset of the parameters are
-     * not valid or not supported, it is unspecified whether the function
-     * returns #PSA_ERROR_NOT_PERMITTED, #PSA_ERROR_NOT_SUPPORTED or
-     * #PSA_ERROR_INVALID_ARGUMENT. */
-    PSA_ERROR_NOT_PERMITTED,
-    /** An output buffer is too small.
-     *
-     * Applications can call the `PSA_xxx_SIZE` macro listed in the function
-     * description to determine a sufficient buffer size.
-     *
-     * Implementations should preferably return this error code only
-     * in cases when performing the operation with a larger output
-     * buffer would succeed. However implementations may return this
-     * error if a function has invalid or unsupported parameters in addition
-     * to the parameters that determine the necessary output buffer size. */
-    PSA_ERROR_BUFFER_TOO_SMALL,
-    /** A slot is occupied, but must be empty to carry out the
-     * requested action.
-     *
-     * If the slot number is invalid (i.e. the requested action could
-     * not be performed even after erasing the slot's content),
-     * implementations shall return #PSA_ERROR_INVALID_ARGUMENT instead. */
-    PSA_ERROR_OCCUPIED_SLOT,
-    /** A slot is empty, but must be occupied to carry out the
-     * requested action.
-     *
-     * If the slot number is invalid (i.e. the requested action could
-     * not be performed even after creating appropriate content in the slot),
-     * implementations shall return #PSA_ERROR_INVALID_ARGUMENT instead. */
-    PSA_ERROR_EMPTY_SLOT,
-    /** The requested action cannot be performed in the current state.
-     *
-     * Multipart operations return this error when one of the
-     * functions is called out of sequence. Refer to the function
-     * descriptions for permitted sequencing of functions.
-     *
-     * Implementations shall not return this error code to indicate
-     * that a key slot is occupied when it needs to be free or vice versa,
-     * but shall return #PSA_ERROR_OCCUPIED_SLOT or #PSA_ERROR_EMPTY_SLOT
-     * as applicable. */
-    PSA_ERROR_BAD_STATE,
-    /** The parameters passed to the function are invalid.
-     *
-     * Implementations may return this error any time a parameter or
-     * combination of parameters are recognized as invalid.
-     *
-     * Implementations shall not return this error code to indicate
-     * that a key slot is occupied when it needs to be free or vice versa,
-     * but shall return #PSA_ERROR_OCCUPIED_SLOT or #PSA_ERROR_EMPTY_SLOT
-     * as applicable. */
-    PSA_ERROR_INVALID_ARGUMENT,
-    /** There is not enough runtime memory.
-     *
-     * If the action is carried out across multiple security realms, this
-     * error can refer to available memory in any of the security realms. */
-    PSA_ERROR_INSUFFICIENT_MEMORY,
-    /** There is not enough persistent storage.
-     *
-     * Functions that modify the key storage return this error code if
-     * there is insufficient storage space on the host media. In addition,
-     * many functions that do not otherwise access storage may return this
-     * error code if the implementation requires a mandatory log entry for
-     * the requested action and the log storage space is full. */
-    PSA_ERROR_INSUFFICIENT_STORAGE,
-    /** There was a communication failure inside the implementation.
-     *
-     * This can indicate a communication failure between the application
-     * and an external cryptoprocessor or between the cryptoprocessor and
-     * an external volatile or persistent memory. A communication failure
-     * may be transient or permanent depending on the cause.
-     *
-     * \warning If a function returns this error, it is undetermined
-     * whether the requested action has completed or not. Implementations
-     * should return #PSA_SUCCESS on successful completion whenver
-     * possible, however functions may return #PSA_ERROR_COMMUNICATION_FAILURE
-     * if the requested action was completed successfully in an external
-     * cryptoprocessor but there was a breakdown of communication before
-     * the cryptoprocessor could report the status to the application.
-     */
-    PSA_ERROR_COMMUNICATION_FAILURE,
-    /** There was a storage failure that may have led to data loss.
-     *
-     * This error indicates that some persistent storage is corrupted.
-     * It should not be used for a corruption of volatile memory
-     * (use #PSA_ERROR_TAMPERING_DETECTED), for a communication error
-     * between the cryptoprocessor and its external storage (use
-     * #PSA_ERROR_COMMUNICATION_FAILURE), or when the storage is
-     * in a valid state but is full (use #PSA_ERROR_INSUFFICIENT_STORAGE).
-     *
-     * Note that a storage failure does not indicate that any data that was
-     * previously read is invalid. However this previously read data may no
-     * longer be readable from storage.
-     *
-     * When a storage failure occurs, it is no longer possible to ensure
-     * the global integrity of the keystore. Depending on the global
-     * integrity guarantees offered by the implementation, access to other
-     * data may or may not fail even if the data is still readable but
-     * its integrity canont be guaranteed.
-     *
-     * Implementations should only use this error code to report a
-     * permanent storage corruption. However application writers should
-     * keep in mind that transient errors while reading the storage may be
-     * reported using this error code. */
-    PSA_ERROR_STORAGE_FAILURE,
-    /** A hardware failure was detected.
-     *
-     * A hardware failure may be transient or permanent depending on the
-     * cause. */
-    PSA_ERROR_HARDWARE_FAILURE,
-    /** A tampering attempt was detected.
-     *
-     * If an application receives this error code, there is no guarantee
-     * that previously accessed or computed data was correct and remains
-     * confidential. Applications should not perform any security function
-     * and should enter a safe failure state.
-     *
-     * Implementations may return this error code if they detect an invalid
-     * state that cannot happen during normal operation and that indicates
-     * that the implementation's security guarantees no longer hold. Depending
-     * on the implementation architecture and on its security and safety goals,
-     * the implementation may forcibly terminate the application.
-     *
-     * This error code is intended as a last resort when a security breach
-     * is detected and it is unsure whether the keystore data is still
-     * protected. Implementations shall only return this error code
-     * to report an alarm from a tampering detector, to indicate that
-     * the confidentiality of stored data can no longer be guaranteed,
-     * or to indicate that the integrity of previously returned data is now
-     * considered compromised. Implementations shall not use this error code
-     * to indicate a hardware failure that merely makes it impossible to
-     * perform the requested operation (use #PSA_ERROR_COMMUNICATION_FAILURE,
-     * #PSA_ERROR_STORAGE_FAILURE, #PSA_ERROR_HARDWARE_FAILURE,
-     * #PSA_ERROR_INSUFFICIENT_ENTROPY or other applicable error code
-     * instead).
-     *
-     * This error indicates an attack against the application. Implementations
-     * shall not return this error code as a consequence of the behavior of
-     * the application itself. */
-    PSA_ERROR_TAMPERING_DETECTED,
-    /** There is not enough entropy to generate random data needed
-     * for the requested action.
-     *
-     * This error indicates a failure of a hardware random generator.
-     * Application writers should note that this error can be returned not
-     * only by functions whose purpose is to generate random data, such
-     * as key, IV or nonce generation, but also by functions that execute
-     * an algorithm with a randomized result, as well as functions that
-     * use randomization of intermediate computations as a countermeasure
-     * to certain attacks.
-     *
-     * Implementations should avoid returning this error after psa_crypto_init()
-     * has succeeded. Implementations should generate sufficient
-     * entropy during initialization and subsequently use a cryptographically
-     * secure pseudorandom generator (PRNG). However implementations may return
-     * this error at any time if a policy requires the PRNG to be reseeded
-     * during normal operation. */
-    PSA_ERROR_INSUFFICIENT_ENTROPY,
-    /** The signature, MAC or hash is incorrect.
-     *
-     * Verification functions return this error if the verification
-     * calculations completed successfully, and the value to be verified
-     * was determined to be incorrect.
-     *
-     * If the value to verify has an invalid size, implementations may return
-     * either #PSA_ERROR_INVALID_ARGUMENT or #PSA_ERROR_INVALID_SIGNATURE. */
-    PSA_ERROR_INVALID_SIGNATURE,
-    /** The decrypted padding is incorrect.
-     *
-     * \warning In some protocols, when decrypting data, it is essential that
-     * the behavior of the application does not depend on whether the padding
-     * is correct, down to precise timing. Applications should prefer
-     * protocols that use authenticated encryption rather than plain
-     * encryption. If the application must perform a decryption of
-     * unauthenticated data, the application writer should take care not
-     * to reveal whether the padding is invalid.
-     *
-     * Implementations should strive to make valid and invalid padding
-     * as close as possible to indistinguishable to an external observer.
-     * In particular, the timing of a decryption operation should not
-     * depend on the validity of the padding. */
-    PSA_ERROR_INVALID_PADDING,
-    /** An error occurred that does not correspond to any defined
-     * failure cause.
-     *
-     * Implementations may use this error code if none of the other standard
-     * error codes are applicable. */
-    PSA_ERROR_UNKNOWN_ERROR,
-} psa_status_t;
+#if defined(PSA_SUCCESS)
+typedef psa_error_t psa_status_t;
+#else
+typedef int32_t psa_status_t;
+/** The action was completed successfully. */
+#define PSA_SUCCESS ((psa_status_t)0)
+#endif // PSA_SUCCESS
+
+/** The requested operation or a parameter is not supported
+ * by this implementation.
+ *
+ * Implementations should return this error code when an enumeration
+ * parameter such as a key type, algorithm, etc. is not recognized.
+ * If a combination of parameters is recognized and identified as
+ * not valid, return #PSA_ERROR_INVALID_ARGUMENT instead. */
+#define PSA_ERROR_NOT_SUPPORTED         ((psa_status_t)1)
+
+/** The requested action is denied by a policy.
+ *
+ * Implementations should return this error code when the parameters
+ * are recognized as valid and supported, and a policy explicitly
+ * denies the requested operation.
+ *
+ * If a subset of the parameters of a function call identify a
+ * forbidden operation, and another subset of the parameters are
+ * not valid or not supported, it is unspecified whether the function
+ * returns #PSA_ERROR_NOT_PERMITTED, #PSA_ERROR_NOT_SUPPORTED or
+ * #PSA_ERROR_INVALID_ARGUMENT. */
+#define PSA_ERROR_NOT_PERMITTED         ((psa_status_t)2)
+
+/** An output buffer is too small.
+ *
+ * Applications can call the `PSA_xxx_SIZE` macro listed in the function
+ * description to determine a sufficient buffer size.
+ *
+ * Implementations should preferably return this error code only
+ * in cases when performing the operation with a larger output
+ * buffer would succeed. However implementations may return this
+ * error if a function has invalid or unsupported parameters in addition
+ * to the parameters that determine the necessary output buffer size. */
+#define PSA_ERROR_BUFFER_TOO_SMALL      ((psa_status_t)3)
+
+/** A slot is occupied, but must be empty to carry out the
+ * requested action.
+ *
+ * If the slot number is invalid (i.e. the requested action could
+ * not be performed even after erasing the slot's content),
+ * implementations shall return #PSA_ERROR_INVALID_ARGUMENT instead. */
+#define PSA_ERROR_OCCUPIED_SLOT         ((psa_status_t)4)
+
+/** A slot is empty, but must be occupied to carry out the
+ * requested action.
+ *
+ * If the slot number is invalid (i.e. the requested action could
+ * not be performed even after creating appropriate content in the slot),
+ * implementations shall return #PSA_ERROR_INVALID_ARGUMENT instead. */
+#define PSA_ERROR_EMPTY_SLOT            ((psa_status_t)5)
+
+/** The requested action cannot be performed in the current state.
+ *
+ * Multipart operations return this error when one of the
+ * functions is called out of sequence. Refer to the function
+ * descriptions for permitted sequencing of functions.
+ *
+ * Implementations shall not return this error code to indicate
+ * that a key slot is occupied when it needs to be free or vice versa,
+ * but shall return #PSA_ERROR_OCCUPIED_SLOT or #PSA_ERROR_EMPTY_SLOT
+ * as applicable. */
+#define PSA_ERROR_BAD_STATE             ((psa_status_t)6)
+
+/** The parameters passed to the function are invalid.
+ *
+ * Implementations may return this error any time a parameter or
+ * combination of parameters are recognized as invalid.
+ *
+ * Implementations shall not return this error code to indicate
+ * that a key slot is occupied when it needs to be free or vice versa,
+ * but shall return #PSA_ERROR_OCCUPIED_SLOT or #PSA_ERROR_EMPTY_SLOT
+ * as applicable. */
+#define PSA_ERROR_INVALID_ARGUMENT      ((psa_status_t)7)
+
+/** There is not enough runtime memory.
+ *
+ * If the action is carried out across multiple security realms, this
+ * error can refer to available memory in any of the security realms. */
+#define PSA_ERROR_INSUFFICIENT_MEMORY   ((psa_status_t)8)
+
+/** There is not enough persistent storage.
+ *
+ * Functions that modify the key storage return this error code if
+ * there is insufficient storage space on the host media. In addition,
+ * many functions that do not otherwise access storage may return this
+ * error code if the implementation requires a mandatory log entry for
+ * the requested action and the log storage space is full. */
+#define PSA_ERROR_INSUFFICIENT_STORAGE  ((psa_status_t)9)
+
+/** There was a communication failure inside the implementation.
+ *
+ * This can indicate a communication failure between the application
+ * and an external cryptoprocessor or between the cryptoprocessor and
+ * an external volatile or persistent memory. A communication failure
+ * may be transient or permanent depending on the cause.
+ *
+ * \warning If a function returns this error, it is undetermined
+ * whether the requested action has completed or not. Implementations
+ * should return #PSA_SUCCESS on successful completion whenver
+ * possible, however functions may return #PSA_ERROR_COMMUNICATION_FAILURE
+ * if the requested action was completed successfully in an external
+ * cryptoprocessor but there was a breakdown of communication before
+ * the cryptoprocessor could report the status to the application.
+ */
+#define PSA_ERROR_COMMUNICATION_FAILURE ((psa_status_t)10)
+
+/** There was a storage failure that may have led to data loss.
+ *
+ * This error indicates that some persistent storage is corrupted.
+ * It should not be used for a corruption of volatile memory
+ * (use #PSA_ERROR_TAMPERING_DETECTED), for a communication error
+ * between the cryptoprocessor and its external storage (use
+ * #PSA_ERROR_COMMUNICATION_FAILURE), or when the storage is
+ * in a valid state but is full (use #PSA_ERROR_INSUFFICIENT_STORAGE).
+ *
+ * Note that a storage failure does not indicate that any data that was
+ * previously read is invalid. However this previously read data may no
+ * longer be readable from storage.
+ *
+ * When a storage failure occurs, it is no longer possible to ensure
+ * the global integrity of the keystore. Depending on the global
+ * integrity guarantees offered by the implementation, access to other
+ * data may or may not fail even if the data is still readable but
+ * its integrity canont be guaranteed.
+ *
+ * Implementations should only use this error code to report a
+ * permanent storage corruption. However application writers should
+ * keep in mind that transient errors while reading the storage may be
+ * reported using this error code. */
+#define PSA_ERROR_STORAGE_FAILURE       ((psa_status_t)11)
+
+/** A hardware failure was detected.
+ *
+ * A hardware failure may be transient or permanent depending on the
+ * cause. */
+#define PSA_ERROR_HARDWARE_FAILURE      ((psa_status_t)12)
+
+/** A tampering attempt was detected.
+ *
+ * If an application receives this error code, there is no guarantee
+ * that previously accessed or computed data was correct and remains
+ * confidential. Applications should not perform any security function
+ * and should enter a safe failure state.
+ *
+ * Implementations may return this error code if they detect an invalid
+ * state that cannot happen during normal operation and that indicates
+ * that the implementation's security guarantees no longer hold. Depending
+ * on the implementation architecture and on its security and safety goals,
+ * the implementation may forcibly terminate the application.
+ *
+ * This error code is intended as a last resort when a security breach
+ * is detected and it is unsure whether the keystore data is still
+ * protected. Implementations shall only return this error code
+ * to report an alarm from a tampering detector, to indicate that
+ * the confidentiality of stored data can no longer be guaranteed,
+ * or to indicate that the integrity of previously returned data is now
+ * considered compromised. Implementations shall not use this error code
+ * to indicate a hardware failure that merely makes it impossible to
+ * perform the requested operation (use #PSA_ERROR_COMMUNICATION_FAILURE,
+ * #PSA_ERROR_STORAGE_FAILURE, #PSA_ERROR_HARDWARE_FAILURE,
+ * #PSA_ERROR_INSUFFICIENT_ENTROPY or other applicable error code
+ * instead).
+ *
+ * This error indicates an attack against the application. Implementations
+ * shall not return this error code as a consequence of the behavior of
+ * the application itself. */
+#define PSA_ERROR_TAMPERING_DETECTED    ((psa_status_t)13)
+
+/** There is not enough entropy to generate random data needed
+ * for the requested action.
+ *
+ * This error indicates a failure of a hardware random generator.
+ * Application writers should note that this error can be returned not
+ * only by functions whose purpose is to generate random data, such
+ * as key, IV or nonce generation, but also by functions that execute
+ * an algorithm with a randomized result, as well as functions that
+ * use randomization of intermediate computations as a countermeasure
+ * to certain attacks.
+ *
+ * Implementations should avoid returning this error after psa_crypto_init()
+ * has succeeded. Implementations should generate sufficient
+ * entropy during initialization and subsequently use a cryptographically
+ * secure pseudorandom generator (PRNG). However implementations may return
+ * this error at any time if a policy requires the PRNG to be reseeded
+ * during normal operation. */
+#define PSA_ERROR_INSUFFICIENT_ENTROPY  ((psa_status_t)14)
+
+/** The signature, MAC or hash is incorrect.
+ *
+ * Verification functions return this error if the verification
+ * calculations completed successfully, and the value to be verified
+ * was determined to be incorrect.
+ *
+ * If the value to verify has an invalid size, implementations may return
+ * either #PSA_ERROR_INVALID_ARGUMENT or #PSA_ERROR_INVALID_SIGNATURE. */
+#define PSA_ERROR_INVALID_SIGNATURE     ((psa_status_t)15)
+
+/** The decrypted padding is incorrect.
+ *
+ * \warning In some protocols, when decrypting data, it is essential that
+ * the behavior of the application does not depend on whether the padding
+ * is correct, down to precise timing. Applications should prefer
+ * protocols that use authenticated encryption rather than plain
+ * encryption. If the application must perform a decryption of
+ * unauthenticated data, the application writer should take care not
+ * to reveal whether the padding is invalid.
+ *
+ * Implementations should strive to make valid and invalid padding
+ * as close as possible to indistinguishable to an external observer.
+ * In particular, the timing of a decryption operation should not
+ * depend on the validity of the padding. */
+#define PSA_ERROR_INVALID_PADDING       ((psa_status_t)16)
+
+/** An error occurred that does not correspond to any defined
+ * failure cause.
+ *
+ * Implementations may use this error code if none of the other standard
+ * error codes are applicable. */
+#define PSA_ERROR_UNKNOWN_ERROR         ((psa_status_t)17)
 
 /**
  * \brief Library initialization.