commit 969c5d61f7405b33c8384cedc52b6622679ee204
author Gilles Peskine <Gilles.Peskine@arm.com> Wed Jan 16 15:53:06 2019 +0100
committer Gilles Peskine <Gilles.Peskine@arm.com> Fri Jan 18 18:34:28 2019 +0100
tree c6232e3b11f3c835ca0d3de3943987da8421e3ef
parent 41ac513de8a28b2b7fd0d0b98be84cba50be2d98

Make key agreement the secret input for key derivation

* Documentation
* Proof-of-concept implementation
* Updates to the tests (work in progress)

tests/suites/test_suite_psa_crypto.function

diff --git a/tests/suites/test_suite_psa_crypto.function b/tests/suites/test_suite_psa_crypto.function
index 9b8e01c..f90a7b3 100644
--- a/tests/suites/test_suite_psa_crypto.function
+++ b/tests/suites/test_suite_psa_crypto.function
@@ -405,8 +405,7 @@
 /* We need two keys to exercise key agreement. Exercise the
  * private key against its own public key. */
 static psa_status_t key_agreement_with_self( psa_crypto_generator_t *generator,
-                                             psa_key_handle_t handle,
-                                             psa_algorithm_t alg )
+                                             psa_key_handle_t handle )
 {
     psa_key_type_t private_key_type;
     psa_key_type_t public_key_type;
@@ -428,9 +427,8 @@
                                        public_key, public_key_length,
                                        &public_key_length ) );
 
-    status = psa_key_agreement( generator, handle,
-                                public_key, public_key_length,
-                                alg );
+    status = psa_key_agreement( generator, PSA_KDF_STEP_SECRET, handle,
+                                public_key, public_key_length );
 exit:
     mbedtls_free( public_key );
     return( status );
@@ -448,7 +446,8 @@
     {
         /* We need two keys to exercise key agreement. Exercise the
          * private key against its own public key. */
-        PSA_ASSERT( key_agreement_with_self( &generator, handle, alg ) );
+        PSA_ASSERT( psa_key_derivation_setup( &generator, alg ) );
+        PSA_ASSERT( key_agreement_with_self( &generator, handle ) );
         PSA_ASSERT( psa_generator_read( &generator,
                                         output,
                                         sizeof( output ) ) );
@@ -1791,7 +1790,8 @@
     PSA_ASSERT( psa_import_key( handle, key_type,
                                 key_data->x, key_data->len ) );
 
-    status = key_agreement_with_self( &generator, handle, exercise_alg );
+    PSA_ASSERT( psa_key_derivation_setup( &generator, exercise_alg ) );
+    status = key_agreement_with_self( &generator, handle );
 
     if( policy_alg == exercise_alg &&
         ( policy_usage & PSA_KEY_USAGE_DERIVE ) != 0 )
@@ -3848,10 +3848,10 @@
                                 our_key_data->x,
                                 our_key_data->len ) );
 
-    TEST_EQUAL( psa_key_agreement( &generator,
+    PSA_ASSERT( psa_key_derivation_setup( &generator, alg ) );
+    TEST_EQUAL( psa_key_agreement( &generator, PSA_KDF_STEP_SECRET,
                                    our_key,
-                                   peer_key_data->x, peer_key_data->len,
-                                   alg ),
+                                   peer_key_data->x, peer_key_data->len ),
                 expected_status_arg );
 
 exit:
@@ -3887,10 +3887,10 @@
                                 our_key_data->x,
                                 our_key_data->len ) );
 
-    PSA_ASSERT( psa_key_agreement( &generator,
+    PSA_ASSERT( psa_key_derivation_setup( &generator, alg ) );
+    PSA_ASSERT( psa_key_agreement( &generator, PSA_KDF_STEP_SECRET,
                                    our_key,
-                                   peer_key_data->x, peer_key_data->len,
-                                   alg ) );
+                                   peer_key_data->x, peer_key_data->len ) );
 
     /* Test the advertized capacity. */
     PSA_ASSERT( psa_get_generator_capacity(
@@ -3944,10 +3944,10 @@
                                 our_key_data->x,
                                 our_key_data->len ) );
 
-    PSA_ASSERT( psa_key_agreement( &generator,
+    PSA_ASSERT( psa_key_derivation_setup( &generator, alg ) );
+    PSA_ASSERT( psa_key_agreement( &generator, PSA_KDF_STEP_SECRET,
                                    our_key,
-                                   peer_key_data->x, peer_key_data->len,
-                                   alg ) );
+                                   peer_key_data->x, peer_key_data->len ) );
 
     PSA_ASSERT( psa_generator_read( &generator,
                                     actual_output,