commit 70f46e17e8c08022c9c0303074165976c745cc3f
author Gilles Peskine <Gilles.Peskine@arm.com> Mon Aug 20 15:07:53 2018 +0200
committer Gilles Peskine <Gilles.Peskine@arm.com> Mon Oct 08 14:45:35 2018 +0200
tree c1cf8288bcdc1062dba53988daa7bb24a7be8ddd
parent be00a71c90991c867247b2c554c5e5bafc951451

New macro PSA_ALG_AEAD_WITH_DEFAULT_TAG_LENGTH

Useful to analyze algorithm values.

include/psa/crypto.h

diff --git a/include/psa/crypto.h b/include/psa/crypto.h
index c22e853..ac38529 100644
--- a/include/psa/crypto.h
+++ b/include/psa/crypto.h
@@ -913,6 +913,24 @@
      ((tag_length) << PSA_AEAD_TAG_LENGTH_OFFSET &                      \
       PSA_ALG_AEAD_TAG_LENGTH_MASK))
 
+/** Calculate the corresponding AEAD algorithm with the default tag length.
+ *
+ * \param alg   An AEAD algorithm (\c PSA_ALG_XXX value such that
+ *              #PSA_ALG_IS_AEAD(\p alg) is true).
+ *
+ * \return      The corresponding AEAD algorithm with the default tag length
+ *              for that algorithm.
+ */
+#define PSA_ALG_AEAD_WITH_DEFAULT_TAG_LENGTH(alg)                       \
+    (                                                                   \
+        PSA__ALG_AEAD_WITH_DEFAULT_TAG_LENGTH__CASE(alg, PSA_ALG_CCM)   \
+        PSA__ALG_AEAD_WITH_DEFAULT_TAG_LENGTH__CASE(alg, PSA_ALG_GCM)   \
+        0)
+#define PSA__ALG_AEAD_WITH_DEFAULT_TAG_LENGTH__CASE(alg, ref) \
+    PSA_ALG_AEAD_WITH_TAG_LENGTH(alg, 0) == \
+    PSA_ALG_AEAD_WITH_TAG_LENGTH(ref, 0) ?  \
+    ref :
+
 #define PSA_ALG_RSA_PKCS1V15_SIGN_BASE          ((psa_algorithm_t)0x10020000)
 /** RSA PKCS#1 v1.5 signature with hashing.
  *