gpg: Prepare Kyber encryption code for more variants.

* common/openpgp-oid.c (oidtable): Add field kem_algo.
(openpgp_oid_to_kem_algo): New.
* g10/pkglue.c (do_encrypt_kem): Add support for Kyber1024.
--
GnuPG-bug-id: 6815

2 files changed, 27 insertions, 2 deletions

diff --git a/common/openpgp-oid.c b/common/openpgp-oid.c
index 4b59c1aeb..74541a03f 100644
--- a/common/openpgp-oid.c
+++ b/common/openpgp-oid.c
@@ -45,14 +45,15 @@ static struct {
   const char *alias;  /* NULL or alternative name of the curve.  */
   const char *abbr;   /* NULL or abbreviated name of the curve.  */
   int pubkey_algo;    /* Required OpenPGP algo or 0 for ECDSA/ECDH.  */
+  enum gcry_kem_algos kem_algo; /* 0 or the KEM algorithm for PQC.   */
 } oidtable[] = {
 
   { "Curve25519", "1.3.6.1.4.1.3029.1.5.1", 255, "cv25519", NULL,
-    PUBKEY_ALGO_ECDH },
+    PUBKEY_ALGO_ECDH, GCRY_KEM_RAW_X25519 /* only during development */},
   { "Ed25519",    "1.3.6.1.4.1.11591.15.1", 255, "ed25519", NULL,
     PUBKEY_ALGO_EDDSA },
   { "Curve25519", "1.3.101.110",            255, "cv25519", NULL,
-    PUBKEY_ALGO_ECDH },
+    PUBKEY_ALGO_ECDH, GCRY_KEM_RAW_X25519 },
   { "Ed25519",    "1.3.101.112",            255, "ed25519", NULL,
     PUBKEY_ALGO_EDDSA },
   { "X448",       "1.3.101.111",            448, "cv448",   NULL,
@@ -542,6 +543,29 @@ openpgp_oid_or_name_to_curve (const char *oidname, int canon)
 }
 
 
+/* Return the KEM algorithm id for the curve with OIDNAME.  */
+enum gcry_kem_algos
+openpgp_oid_to_kem_algo (const char *oidname)
+{
+  int i;
+
+  if (!oidname)
+    return 0;
+
+  for (i=0; oidtable[i].name; i++)
+    if (!strcmp (oidtable[i].oidstr, oidname))
+      return oidtable[i].kem_algo;
+
+  for (i=0; oidtable[i].name; i++)
+    if (!ascii_strcasecmp (oidtable[i].name, oidname)
+        || (oidtable[i].alias
+            && !ascii_strcasecmp (oidtable[i].alias, oidname)))
+      return oidtable[i].kem_algo;
+
+  return 0;
+}
+
+
 /* Return true if the curve with NAME is supported.  */
 static int
 curve_supported_p (const char *name)
diff --git a/common/util.h b/common/util.h
index 5c953a8a1..238b8f1bc 100644
--- a/common/util.h
+++ b/common/util.h
@@ -227,6 +227,7 @@ int openpgp_oidbuf_is_cv25519 (const void *buf, size_t len);
 int openpgp_oid_is_cv25519 (gcry_mpi_t a);
 int openpgp_oid_is_cv448 (gcry_mpi_t a);
 int openpgp_oid_is_ed448 (gcry_mpi_t a);
+enum gcry_kem_algos openpgp_oid_to_kem_algo (const char *oidname);
 const char *openpgp_curve_to_oid (const char *name,
                                   unsigned int *r_nbits, int *r_algo);
 const char *openpgp_oid_to_curve (const char *oid, int mode);