diff --git a/library/psa_crypto.c b/library/psa_crypto.c
index fe30729..8b25dac 100644
--- a/library/psa_crypto.c
+++ b/library/psa_crypto.c
@@ -3453,7 +3453,7 @@
 void mbedtls_psa_crypto_free( void )
 {
     psa_key_slot_t key;
-    for( key = 1; key < PSA_KEY_SLOT_COUNT; key++ )
+    for( key = 1; key <= PSA_KEY_SLOT_COUNT; key++ )
         psa_destroy_key( key );
     mbedtls_ctr_drbg_free( &global_data.ctr_drbg );
     mbedtls_entropy_free( &global_data.entropy );