Parametrize Diffie-Hellman keys by a group identifier
Parametrize finite-field Diffie-Hellman key types with a DH group
identifier, in the same way elliptic curve keys are parametrized with
an EC curve identifier.
Define the DH groups from the TLS registry (these are the groups from
RFC 7919).
Replicate the macro definitions and the metadata tests from elliptic
curve identifiers to DH group identifiers.
Define PSA_DH_GROUP_CUSTOM as an implementation-specific extension for
which domain parameters are used to specify the group.
diff --git a/include/psa/crypto_values.h b/include/psa/crypto_values.h
index c54fc9a..6cd22c8 100644
--- a/include/psa/crypto_values.h
+++ b/include/psa/crypto_values.h
@@ -492,14 +492,45 @@
#define PSA_ECC_CURVE_CURVE25519 ((psa_ecc_curve_t) 0x001d)
#define PSA_ECC_CURVE_CURVE448 ((psa_ecc_curve_t) 0x001e)
-/** Diffie-Hellman key exchange public key. */
-#define PSA_KEY_TYPE_DH_PUBLIC_KEY ((psa_key_type_t)0x60040000)
-/** Diffie-Hellman key exchange key pair (private and public key). */
-#define PSA_KEY_TYPE_DH_KEYPAIR ((psa_key_type_t)0x70040000)
-/** Whether a key type is a Diffie-Hellman key exchange key (pair or
- * public-only). */
-#define PSA_KEY_TYPE_IS_DH(type) \
- (PSA_KEY_TYPE_PUBLIC_KEY_OF_KEYPAIR(type) == PSA_KEY_TYPE_DH_PUBLIC_KEY)
+#define PSA_KEY_TYPE_DH_PUBLIC_KEY_BASE ((psa_key_type_t)0x60040000)
+#define PSA_KEY_TYPE_DH_KEYPAIR_BASE ((psa_key_type_t)0x70040000)
+#define PSA_KEY_TYPE_DH_GROUP_MASK ((psa_key_type_t)0x0000ffff)
+/** Diffie-Hellman key pair. */
+#define PSA_KEY_TYPE_DH_KEYPAIR(group) \
+ (PSA_KEY_TYPE_DH_KEYPAIR_BASE | (group))
+/** Diffie-Hellman public key. */
+#define PSA_KEY_TYPE_DH_PUBLIC_KEY(group) \
+ (PSA_KEY_TYPE_DH_PUBLIC_KEY_BASE | (group))
+
+/** Whether a key type is a Diffie-Hellman key (pair or public-only). */
+#define PSA_KEY_TYPE_IS_DH(type) \
+ ((PSA_KEY_TYPE_PUBLIC_KEY_OF_KEYPAIR(type) & \
+ ~PSA_KEY_TYPE_DH_GROUP_MASK) == PSA_KEY_TYPE_DH_PUBLIC_KEY_BASE)
+/** Whether a key type is a Diffie-Hellman key pair. */
+#define PSA_KEY_TYPE_IS_DH_KEYPAIR(type) \
+ (((type) & ~PSA_KEY_TYPE_DH_GROUP_MASK) == \
+ PSA_KEY_TYPE_DH_KEYPAIR_BASE)
+/** Whether a key type is a Diffie-Hellman public key. */
+#define PSA_KEY_TYPE_IS_DH_PUBLIC_KEY(type) \
+ (((type) & ~PSA_KEY_TYPE_DH_GROUP_MASK) == \
+ PSA_KEY_TYPE_DH_PUBLIC_KEY_BASE)
+
+/** Extract the group from a Diffie-Hellman key type. */
+#define PSA_KEY_TYPE_GET_GROUP(type) \
+ ((psa_dh_group_t) (PSA_KEY_TYPE_IS_DH(type) ? \
+ ((type) & PSA_KEY_TYPE_DH_GROUP_MASK) : \
+ 0))
+
+/* The encoding of group identifiers is currently aligned with the
+ * TLS Supported Groups Registry (formerly known as the
+ * TLS EC Named Curve Registry)
+ * https://www.iana.org/assignments/tls-parameters/tls-parameters.xhtml#tls-parameters-8
+ * The values are defined by RFC 7919. */
+#define PSA_DH_GROUP_FFDHE2048 ((psa_dh_group_t) 0x0100)
+#define PSA_DH_GROUP_FFDHE3072 ((psa_dh_group_t) 0x0101)
+#define PSA_DH_GROUP_FFDHE4096 ((psa_dh_group_t) 0x0102)
+#define PSA_DH_GROUP_FFDHE6144 ((psa_dh_group_t) 0x0103)
+#define PSA_DH_GROUP_FFDHE8192 ((psa_dh_group_t) 0x0104)
/** The block size of a block cipher.
*