--- /dev/null
+/* LibTomCrypt, modular cryptographic library -- Tom St Denis
+ *
+ * LibTomCrypt is a library that provides various cryptographic
+ * algorithms in a highly modular and flexible manner.
+ *
+ * The library is free for all purposes without any express
+ * guarantee it works.
+ */
+
+#include "tomcrypt.h"
+
+#ifdef LTC_MDH
+
+/**
+ Import a DH key from a binary packet
+ @param in The packet to read
+ @param inlen The length of the input packet
+ @param key [out] Where to import the key to
+ @return CRYPT_OK if successful, on error all allocated memory is freed automatically
+*/
+int dh_import(const unsigned char *in, unsigned long inlen, dh_key *key)
+{
+ unsigned char flags[1];
+ int err;
+ unsigned long version;
+
+ LTC_ARGCHK(in != NULL);
+ LTC_ARGCHK(key != NULL);
+
+ /* init */
+ if ((err = mp_init_multi(&key->x, &key->y, &key->base, &key->prime, NULL)) != CRYPT_OK) {
+ return err;
+ }
+
+ /* find out what type of key it is */
+ err = der_decode_sequence_multi(in, inlen,
+ LTC_ASN1_SHORT_INTEGER, 1UL, &version,
+ LTC_ASN1_BIT_STRING, 1UL, &flags,
+ LTC_ASN1_EOL, 0UL, NULL);
+ if (err != CRYPT_OK && err != CRYPT_INPUT_TOO_LONG) {
+ goto error;
+ }
+
+ if (version == 0) {
+ if (flags[0] == 1) {
+ key->type = PK_PRIVATE;
+ if ((err = der_decode_sequence_multi(in, inlen,
+ LTC_ASN1_SHORT_INTEGER, 1UL, &version,
+ LTC_ASN1_BIT_STRING, 1UL, flags,
+ LTC_ASN1_INTEGER, 1UL, key->prime,
+ LTC_ASN1_INTEGER, 1UL, key->base,
+ LTC_ASN1_INTEGER, 1UL, key->x,
+ LTC_ASN1_EOL, 0UL, NULL)) != CRYPT_OK) {
+ goto error;
+ }
+ /* compute public key: y = (base ^ x) mod prime */
+ if ((err = mp_exptmod(key->base, key->x, key->prime, key->y)) != CRYPT_OK) {
+ goto error;
+ }
+ }
+ else if (flags[0] == 0) {
+ key->type = PK_PUBLIC;
+ if ((err = der_decode_sequence_multi(in, inlen,
+ LTC_ASN1_SHORT_INTEGER, 1UL, &version,
+ LTC_ASN1_BIT_STRING, 1UL, flags,
+ LTC_ASN1_INTEGER, 1UL, key->prime,
+ LTC_ASN1_INTEGER, 1UL, key->base,
+ LTC_ASN1_INTEGER, 1UL, key->y,
+ LTC_ASN1_EOL, 0UL, NULL)) != CRYPT_OK) {
+ goto error;
+ }
+ }
+ else {
+ err = CRYPT_INVALID_PACKET;
+ goto error;
+ }
+ }
+ else {
+ err = CRYPT_INVALID_PACKET;
+ goto error;
+ }
+
+ /* check public key */
+ if ((err = dh_check_pubkey(key)) != CRYPT_OK) {
+ goto error;
+ }
+
+ return CRYPT_OK;
+
+error:
+ dh_free(key);
+ return err;
+}
+
+#endif /* LTC_MDH */
+
+/* ref: $Format:%D$ */
+/* git commit: $Format:%H$ */
+/* commit time: $Format:%ai$ */