Declare multipart AEAD functions
Declare and document multipart AEAD functions.
This commit does not contain any implementation or tests.
diff --git a/include/psa/crypto_sizes.h b/include/psa/crypto_sizes.h
index 5ad695a..d4182f5 100644
--- a/include/psa/crypto_sizes.h
+++ b/include/psa/crypto_sizes.h
@@ -268,6 +268,27 @@
(plaintext_length) + PSA_AEAD_TAG_LENGTH(alg) : \
0)
+/** The maximum size of the output of psa_aead_finish(), in bytes.
+ *
+ * If the size of the ciphertext buffer is at least this large, it is
+ * guaranteed that psa_aead_finish() will not fail due to an
+ * insufficient buffer size. Depending on the algorithm, the actual size of
+ * the ciphertext may be smaller.
+ *
+ * \param alg An AEAD algorithm
+ * (\c PSA_ALG_XXX value such that
+ * #PSA_ALG_IS_AEAD(alg) is true).
+ *
+ * \return The maximum trailing ciphertext size for the
+ * specified algorithm.
+ * If the AEAD algorithm is not recognized, return 0.
+ * An implementation may return either 0 or a
+ * correct size for an AEAD algorithm that it
+ * recognizes, but does not support.
+ */
+#define PSA_AEAD_FINISH_OUTPUT_SIZE(alg, plaintext_length) \
+ ((size_t)0)
+
/** The maximum size of the output of psa_aead_decrypt(), in bytes.
*
* If the size of the plaintext buffer is at least this large, it is