Add and update size macros for ciphers and keys
Signed-off-by: gabor-mezei-arm <gabor.mezei@arm.com>
diff --git a/include/psa/crypto_sizes.h b/include/psa/crypto_sizes.h
index 119acaa..b1d329c 100644
--- a/include/psa/crypto_sizes.h
+++ b/include/psa/crypto_sizes.h
@@ -785,4 +785,60 @@
*/
#define PSA_CIPHER_IV_MAX_SIZE 16
+/** The maximum size of the output of psa_cipher_encrypt(), in bytes.
+ *
+ * If the size of the output buffer is at least this large, it is guaranteed
+ * that psa_cipher_encrypt() will not fail due to an insufficient buffer size.
+ * Depending on the algorithm, the actual size of the output might be smaller.
+ *
+ * See also #PSA_CIPHER_ENCRYPT_OUTPUT_MAX_SIZE.
+ *
+ * \param key_type A symmetric key type that is compatible with algorithm
+ * alg.
+ * \param alg A cipher algorithm (\c PSA_ALG_XXX value such that
+ * #PSA_ALG_IS_CIPHER(\p alg) is true).
+ * \param input_length Size of the input in bytes.
+ *
+ * \return A sufficient output size for the specified key type and
+ * algorithm. If the key type or cipher algorithm is not
+ * recognized, or the parameters are incompatible,
+ * return 0. An implementation can return either 0 or
+ * a correct size for a key type and cipher algorithm
+ * that it recognizes, but does not support.
+ */
+#define PSA_CIPHER_ENCRYPT_OUTPUT_SIZE(key_type, alg, input_length) \
+ (PSA_ALG_IS_CIPHER(alg) && PSA_KEY_TYPE_IS_SYMMETRIC(key_type) ? \
+ (alg == PSA_ALG_CBC_PKCS7 ? \
+ (((input_length) + PSA_CIPHER_IV_LENGTH(key_type, alg) + 1) / \
+ PSA_BLOCK_CIPHER_BLOCK_LENGTH(key_type) + 1) * \
+ PSA_BLOCK_CIPHER_BLOCK_LENGTH(key_type) : \
+ (input_length) + PSA_CIPHER_IV_LENGTH(key_type, alg) ) : \
+ 0)
+
+/** The maximum size of the output of psa_cipher_decrypt(), in bytes.
+ *
+ * If the size of the output buffer is at least this large, it is guaranteed
+ * that psa_cipher_decrypt() will not fail due to an insufficient buffer size.
+ * Depending on the algorithm, the actual size of the output might be smaller.
+ *
+ * See also #PSA_CIPHER_DECRYPT_OUTPUT_MAX_SIZE.
+ *
+ * \param key_type A symmetric key type that is compatible with algorithm
+ * alg.
+ * \param alg A cipher algorithm (\c PSA_ALG_XXX value such that
+ * #PSA_ALG_IS_CIPHER(\p alg) is true).
+ * \param input_length Size of the input in bytes.
+ *
+ * \return A sufficient output size for the specified key type and
+ * algorithm. If the key type or cipher algorithm is not
+ * recognized, or the parameters are incompatible,
+ * return 0. An implementation can return either 0 or
+ * a correct size for a key type and cipher algorithm
+ * that it recognizes, but does not support.
+ */
+#define PSA_CIPHER_DECRYPT_OUTPUT_SIZE(key_type, alg, input_length) \
+ (PSA_ALG_IS_CIPHER(alg) && PSA_KEY_TYPE_IS_SYMMETRIC(key_type) ? \
+ (input_length) : \
+ 0)
+
#endif /* PSA_CRYPTO_SIZES_H */
diff --git a/include/psa/crypto_values.h b/include/psa/crypto_values.h
index 7002631..a7bc5ae 100644
--- a/include/psa/crypto_values.h
+++ b/include/psa/crypto_values.h
@@ -354,6 +354,9 @@
(((type) & PSA_KEY_TYPE_CATEGORY_MASK) == PSA_KEY_TYPE_CATEGORY_RAW || \
((type) & PSA_KEY_TYPE_CATEGORY_MASK) == PSA_KEY_TYPE_CATEGORY_SYMMETRIC)
+/** Whether a key type is symmetric. */
+#define PSA_KEY_TYPE_IS_SYMMETRIC(type) \
+ (((type) & PSA_KEY_TYPE_CATEGORY_MASK) == PSA_KEY_TYPE_CATEGORY_SYMMETRIC)
/** Whether a key type is asymmetric: either a key pair or a public key. */
#define PSA_KEY_TYPE_IS_ASYMMETRIC(type) \
(((type) & PSA_KEY_TYPE_CATEGORY_MASK \
