Declare ChaCha20 cipher and AEAD
Declare algorithms for ChaCha20 and ChaCha20-Poly1305, and a
corresponding (common) key type.
Don't declare Poly1305 as a separate algorithm because it's a one-time
authenticator, not a MAC, so the API isn't suitable for it (no way to
use a nonce).
diff --git a/include/psa/crypto_values.h b/include/psa/crypto_values.h
index d01367d..9777ae9 100644
--- a/include/psa/crypto_values.h
+++ b/include/psa/crypto_values.h
@@ -402,6 +402,15 @@
* legacy protocols. */
#define PSA_KEY_TYPE_ARC4 ((psa_key_type_t)0x40000004)
+/** Key for the ChaCha20 stream cipher or the Chacha20-Poly1305 AEAD algorithm.
+ *
+ * ChaCha20 and the ChaCha20_Poly1305 construction are defined in RFC 7539.
+ *
+ * Implementations must support 12-byte nonces, may support 8-byte nonces,
+ * and should reject other sizes.
+ */
+#define PSA_KEY_TYPE_CHACHA20 ((psa_key_type_t)0x40000005)
+
/** RSA public key. */
#define PSA_KEY_TYPE_RSA_PUBLIC_KEY ((psa_key_type_t)0x60010000)
/** RSA key pair (private and public key). */
@@ -836,6 +845,18 @@
*/
#define PSA_ALG_ARC4 ((psa_algorithm_t)0x04800001)
+/** The ChaCha20 stream cipher.
+ *
+ * ChaCha20 is defined in RFC 7539.
+ *
+ * The nonce size for psa_cipher_set_iv() or psa_cipher_generate_iv()
+ * must be 12.
+ *
+ * The initial block counter is always 0.
+ *
+ */
+#define PSA_ALG_CHACHA20 ((psa_algorithm_t)0x04800005)
+
/** The CTR stream cipher mode.
*
* CTR is a stream cipher which is built from a block cipher.
@@ -900,6 +921,11 @@
/** The Chacha20-Poly1305 AEAD algorithm.
*
* The ChaCha20_Poly1305 construction is defined in RFC 7539.
+ *
+ * Implementations must support 12-byte nonces, may support 8-byte nonces,
+ * and should reject other sizes.
+ *
+ * Implementations must support 16-byte tags and should reject other sizes.
*/
#define PSA_ALG_CHACHA20_POLY1305 ((psa_algorithm_t)0x06001005)
@@ -945,6 +971,7 @@
( \
PSA__ALG_AEAD_WITH_DEFAULT_TAG_LENGTH__CASE(aead_alg, PSA_ALG_CCM) \
PSA__ALG_AEAD_WITH_DEFAULT_TAG_LENGTH__CASE(aead_alg, PSA_ALG_GCM) \
+ PSA__ALG_AEAD_WITH_DEFAULT_TAG_LENGTH__CASE(aead_alg, PSA_ALG_CHACHA20_POLY1305) \
0)
#define PSA__ALG_AEAD_WITH_DEFAULT_TAG_LENGTH__CASE(aead_alg, ref) \
PSA_ALG_AEAD_WITH_TAG_LENGTH(aead_alg, 0) == \