1 files changed, 97 insertions, 0 deletions
diff --git a/ecc.c b/ecc.c
index cf67ec0..873a92a 100644
--- a/ecc.c
+++ b/ecc.c
@@ -1,6 +1,37 @@
+#include "includes.h"
+#include "options.h"
+#include "ecc.h"
+
 #ifdef DROPBEAR_ECC
 
+#ifdef DROPBEAR_ECC_256
+const struct ecc_curve_secp256r1 {
+	.ltc_set = &ltc_ecc_sets[0],
+	.hash_desc = sha256_desc,
+	.name = "secp256r1"
+};
+#endif
+
+
+#ifdef DROPBEAR_ECC_384
+const struct ecc_curve_secp384r1 {
+	.ltc_set = &ltc_ecc_sets[1],
+	.hash_desc = sha384_desc,
+	.name = "secp384r1"
+};
+#endif
+
+#ifdef DROPBEAR_ECC_256
+const struct ecc_curve_secp256r1 {
+	.ltc_set = &ltc_ecc_sets[0],
+	.hash_desc = sha256_desc,
+	.name = "secp256r1"
+};
+#endif
+
+
 void buf_put_ecc_key_string(buffer *buf, ecc_key *key) {
+	// XXX point compression
 	int len = key->dp->size*2 + 1;
 	buf_putint(len);
 	int err = ecc_ansi_x963_export(key, buf_getwriteptr(buf, len), &len);
@@ -13,5 +44,71 @@ void buf_put_ecc_key_string(buffer *buf, ecc_key *key) {
 int buf_get_ecc_key_string(buffer *buf, ecc_key *key) {
 }
 
+// a modified version of libtomcrypt's "ecc_shared_secret" to output
+// a mp_int instead.
+mp_int * dropbear_ecc_shared_secret(ecc_key *public_key, ecc_key *private_key)
+{
+   ecc_point *result = NULL
+   mp_int *prime = NULL, *shared_secret = NULL;
+   int ret = DROPBEAR_FAILURE;
+
+   /* type valid? */
+   if (private_key->type != PK_PRIVATE) {
+   	goto done;
+   }
+
+   if (private_key->dp != public_key->dp) {
+   	goto done;
+   }
+
+#if 0
+   // XXX - possibly not neccessary tests?
+   if (ltc_ecc_is_valid_idx(private_key->idx) == 0 || ltc_ecc_is_valid_idx(public_key->idx) == 0) {
+   	goto done;
+   }
+
+   if (XSTRCMP(private_key->dp->name, public_key->dp->name) != 0) {
+   	goto done;
+   }
+#endif
+
+   /* make new point */
+   result = ltc_ecc_new_point();
+   if (result == NULL) {
+      goto done;
+   }
+
+   prime = m_malloc(sizeof(*prime));
+   m_mp_init(prime);
+
+   if (mp_read_radix(prime, (char *)private_key->dp->prime, 16) != CRYPT_OK) { 
+	   	goto done; 
+   }
+   if (ltc_mp.ecc_ptmul(private_key->k, &public_key->pubkey, result, prime, 1) != CRYPT_OK) { 
+	   	goto done; 
+   }
+
+   err = DROPBEAR_SUCCESS;
+done:
+	if (err == DROPBEAR_SUCCESS) {
+		shared_secret = prime;
+		prime = NULL;
+	}
+
+	if (prime) {
+	   mp_clear(prime);
+	   m_free(prime);
+	}
+   ltc_ecc_del_point(result);
+
+   if (err == DROPBEAR_FAILURE) {
+   	 dropbear_exit("ECC error");
+   }
+
+   return shared_secret;
+   return err;
+}
+
+}
 
 #endif