diff --git a/include/psa/crypto.h b/include/psa/crypto.h
index 04e6b47..6caa62a 100644
--- a/include/psa/crypto.h
+++ b/include/psa/crypto.h
@@ -89,6 +89,10 @@
     PSA_ERROR_INVALID_SIGNATURE,
     /** The decrypted padding is incorrect. */
     PSA_ERROR_INVALID_PADDING,
+    /** The key lifetime value is incorrect. */
+    PSA_ERROR_INVALID_LIFETIME,
+    /** The key lifetime can not be changed. */
+    PSA_ERROR_KEY_LIFETIME_CHANGE,
     /** An error occurred that does not correspond to any defined
         failure cause. */
     PSA_ERROR_UNKNOWN_ERROR,
@@ -596,18 +600,47 @@
 /** \brief Retrieve the lifetime of a key slot.
  *
  * The assignment of lifetimes to slots is implementation-dependent.
+ * 
+ * \param key           Slot whose content is to be exported. This must
+ *                      be an occupied key slot.
+ * \param lifetime      On success, the lifetime value.
+ * 
+ * \retval PSA_SUCCESS
+ *         Success.
+ * \retval PSA_ERROR_INVALID_ARGUMENT
+ *         The key slot is invalid,
+ *         or the key data is not correctly formatted.
+ * \retval PSA_ERROR_EMPTY_SLOT
+ *         The key slot is not occupied.         
  */
 psa_status_t psa_get_key_lifetime(psa_key_slot_t key,
                                   psa_key_lifetime_t *lifetime);
 
 /** \brief Change the lifetime of a key slot.
+ * 
+ * \note   In case a key slot has PSA_KEY_LIFETIME_WRITE_ONCE lifetime, 
+ *         it can not be changed and trying to set new value will return
+ *         an error
  *
- * Whether the lifetime of a key slot can be changed at all, and if so
- * whether the lifetime of an occupied key slot can be changed, is
- * implementation-dependent.
+ * \param key           Slot whose content is to be exported. This must
+ *                      be an occupied key slot.
+ * \param lifetime      The lifetime value to be set for the given key.
+ * 
+ * \retval PSA_SUCCESS
+ *         Success.
+ * \retval PSA_ERROR_INVALID_ARGUMENT
+ *         The key slot is invalid,
+ *         or the key data is not correctly formatted.
+ * \retval PSA_ERROR_EMPTY_SLOT
+ *         The key slot is not occupied.
+ * \retval PSA_ERROR_INVALID_LIFETIME
+ *         The lifetime value is not valid.
+ * \retval PSA_ERROR_KEY_LIFETIME_CHANGE
+ *         The key slot already has PSA_KEY_LIFETIME_WRITE_ONCE value,
+ *         and can not be changed.
  */
 psa_status_t psa_set_key_lifetime(psa_key_slot_t key,
-                                  const psa_key_lifetime_t *lifetime);
+                                  const psa_key_lifetime_t lifetime);
 
 /**@}*/
 
diff --git a/library/psa_crypto.c b/library/psa_crypto.c
index c93da95..5ba60e1 100644
--- a/library/psa_crypto.c
+++ b/library/psa_crypto.c
@@ -96,6 +96,7 @@
 
 typedef struct {
     psa_key_type_t type;
+    psa_key_lifetime_t lifetime;
     union {
         struct raw_data {
             uint8_t *data;
@@ -362,6 +363,7 @@
     }
 
     slot->type = type;
+    slot->lifetime = 0;
     return( PSA_SUCCESS );
 }
 
@@ -1260,6 +1262,53 @@
 }
 
 
+/****************************************************************/
+/* Key Lifetime */
+/****************************************************************/
+
+psa_status_t psa_get_key_lifetime(psa_key_slot_t key,
+                                  psa_key_lifetime_t *lifetime)
+{
+    key_slot_t *slot;
+
+    if( key == 0 || key > MBEDTLS_PSA_KEY_SLOT_COUNT )
+        return( PSA_ERROR_INVALID_ARGUMENT );
+
+    slot = &global_data.key_slots[key];
+
+    if( slot->type == PSA_KEY_TYPE_NONE )
+        return( PSA_ERROR_EMPTY_SLOT );
+    
+    *lifetime = slot->lifetime;
+
+    return( PSA_SUCCESS );
+}
+
+psa_status_t psa_set_key_lifetime(psa_key_slot_t key,
+                                  const psa_key_lifetime_t lifetime)
+{
+    key_slot_t *slot;
+
+    if( key == 0 || key > MBEDTLS_PSA_KEY_SLOT_COUNT )
+        return( PSA_ERROR_INVALID_ARGUMENT );
+
+    slot = &global_data.key_slots[key];
+    if( slot->type == PSA_KEY_TYPE_NONE )
+        return( PSA_ERROR_EMPTY_SLOT );
+
+    if( lifetime != PSA_KEY_LIFETIME_VOLATILE && 
+        lifetime != PSA_KEY_LIFETIME_PERSISTENT && 
+        lifetime != PSA_KEY_LIFETIME_WRITE_ONCE)
+        return( PSA_ERROR_INVALID_LIFETIME );
+
+    if ( slot->lifetime == PSA_KEY_LIFETIME_WRITE_ONCE )
+        return( PSA_ERROR_KEY_LIFETIME_CHANGE );
+        
+    slot->lifetime = liftime;
+
+    return( PSA_SUCCESS );
+}
+
 
 /****************************************************************/
 /* Module setup */
diff --git a/tests/suites/test_suite_psa_crypto.data b/tests/suites/test_suite_psa_crypto.data
index 4f4bef1..9611c32 100644
--- a/tests/suites/test_suite_psa_crypto.data
+++ b/tests/suites/test_suite_psa_crypto.data
@@ -83,3 +83,24 @@
 
 PSA sign RSA PKCS#1 v1.5 SHA-256, output buffer too small
 sign_fail:PSA_KEY_TYPE_RSA_KEYPAIR:"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":PSA_ALG_RSA_PKCS1V15(PSA_ALG_SHA_256):"ba7816bf8f01cfea414140de5dae2223b00361a396177a9cb410ff61f20015ad":127:PSA_ERROR_BUFFER_TOO_SMALL
+
+PSA Key Lifetime set and get volatile
+key_lifetime:PSA_KEY_LIFETIME_VOLATILE
+
+PSA Key Lifetime set and get persistent
+key_lifetime:PSA_KEY_LIFETIME_PERSISTENT
+
+PSA Key Lifetime set and get write_once
+key_lifetime:PSA_KEY_LIFETIME_WRITE_ONCE
+
+PSA Key Lifetime set fail, invalid key slot
+key_lifetime_set_fail:0:PSA_KEY_LIFETIME_VOLATILE:PSA_ERROR_INVALID_ARGUMENT
+
+PSA Key Lifetime set fail, unoccupied key slot
+key_lifetime_set_fail:2:PSA_KEY_LIFETIME_VOLATILE:PSA_ERROR_EMPTY_SLOT
+
+PSA Key Lifetime set fail, can not change write_once lifetime
+key_lifetime_set_fail:1:PSA_KEY_LIFETIME_WRITE_ONCE:PSA_ERROR_KEY_LIFETIME_CHANGE
+
+PSA Key Lifetime set fail, invalid key lifetime value
+key_lifetime_set_fail:1:PSA_KEY_LIFETIME_PERSISTENT+1:PSA_ERROR_INVALID_LIFETIME
diff --git a/tests/suites/test_suite_psa_crypto.function b/tests/suites/test_suite_psa_crypto.function
index 9381794..d8dddff 100644
--- a/tests/suites/test_suite_psa_crypto.function
+++ b/tests/suites/test_suite_psa_crypto.function
@@ -360,3 +360,68 @@
     mbedtls_psa_crypto_free( );
 }
 /* END_CASE */
+
+/* BEGIN_CASE */
+void key_lifetime( int lifetime_arg )
+{
+    int key_slot = 1;
+    psa_key_type_t key_type = PSA_ALG_CBC_BASE;
+    unsigned char key[32] = {0};
+    psa_key_lifetime_t lifetime_set = (psa_key_lifetime_t) lifetime_arg;
+    psa_key_lifetime_t lifetime_get;
+
+    TEST_ASSERT( key != NULL );
+
+    memset( key, 0x2a, sizeof( key ) );
+ 
+    TEST_ASSERT( psa_crypto_init( ) == PSA_SUCCESS );
+
+    TEST_ASSERT( psa_import_key( key_slot, key_type,
+                                 key, sizeof( key ) ) == PSA_SUCCESS );
+
+    TEST_ASSERT( psa_set_key_lifetime( key_slot, lifetime_set ));
+    
+    TEST_ASSERT( psa_get_key_lifetime( key_slot, &lifetime_get ));
+
+    TEST_ASSERT( lifetime_get == lifetime_set ); 
+
+exit:
+    mbedtls_free( key );
+    psa_destroy_key( key_slot );
+    mbedtls_psa_crypto_free( );
+}
+/* END_CASE */
+
+
+/* BEGIN_CASE */
+void key_lifetime_set_fail( int key_slot_arg, int lifetime_arg, int expected_status_arg )
+{
+    int key_slot = 1;
+    psa_key_type_t key_type = PSA_ALG_CBC_BASE;
+    unsigned char key[32] = {0};
+    psa_key_lifetime_t lifetime_set = (psa_key_lifetime_t) lifetime_arg;
+    psa_status_t actual_status;
+    psa_status_t expected_status = expected_status_arg;
+
+    TEST_ASSERT( key != NULL );
+
+    memset( key, 0x2a, sizeof( key ) );
+ 
+    TEST_ASSERT( psa_crypto_init( ) == PSA_SUCCESS );
+
+    TEST_ASSERT( psa_import_key( key_slot, key_type,
+                                 key, sizeof( key ) ) == PSA_SUCCESS );
+
+    actual_status = psa_set_key_lifetime( key_slot_arg, lifetime_set );
+
+    if( actual_status == PSA_SUCCESS )
+        actual_status = psa_set_key_lifetime( key_slot_arg, lifetime_set );
+    
+    TEST_ASSERT( expected_status == actual_status );
+
+exit:
+    mbedtls_free( key );
+    psa_destroy_key( key_slot );
+    mbedtls_psa_crypto_free( );
+}
+/* END_CASE */