Update to libtomcrypt 1.18.1, merged with Dropbear changes

10 files changed, 898 insertions, 0 deletions

diff --git a/libtomcrypt/src/pk/dh/dh.c b/libtomcrypt/src/pk/dh/dh.c
new file mode 100644
index 0000000..763b007
--- /dev/null
+++ b/libtomcrypt/src/pk/dh/dh.c
@@ -0,0 +1,237 @@
+/* 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
+
+/* This holds the key settings.  ***MUST*** be organized by size from smallest to largest. */
+const ltc_dh_set_type ltc_dh_sets[] = {
+#ifdef LTC_DH768
+{  /* 768-bit MODP Group 1 - https://tools.ietf.org/html/rfc7296#appendix-B.1 */
+   96,
+   "DH-768",
+   "2",
+   "FFFFFFFFFFFFFFFFC90FDAA22168C234C4C6628B80DC1CD1"
+   "29024E088A67CC74020BBEA63B139B22514A08798E3404DD"
+   "EF9519B3CD3A431B302B0A6DF25F14374FE1356D6D51C245"
+   "E485B576625E7EC6F44C42E9A63A3620FFFFFFFFFFFFFFFF"
+},
+#endif
+#ifdef LTC_DH1024
+{  /* 1024-bit MODP Group 2 - https://tools.ietf.org/html/rfc7296#appendix-B.2 */
+   128,
+   "DH-1024",
+   "2",
+   "FFFFFFFFFFFFFFFFC90FDAA22168C234C4C6628B80DC1CD1"
+   "29024E088A67CC74020BBEA63B139B22514A08798E3404DD"
+   "EF9519B3CD3A431B302B0A6DF25F14374FE1356D6D51C245"
+   "E485B576625E7EC6F44C42E9A637ED6B0BFF5CB6F406B7ED"
+   "EE386BFB5A899FA5AE9F24117C4B1FE649286651ECE65381"
+   "FFFFFFFFFFFFFFFF"
+},
+#endif
+#ifdef LTC_DH1536
+{  /* 1536-bit MODP Group 5 - https://tools.ietf.org/html/rfc3526#section-2 */
+   192,
+   "DH-1536",
+   "2",
+   "FFFFFFFFFFFFFFFFC90FDAA22168C234C4C6628B80DC1CD1"
+   "29024E088A67CC74020BBEA63B139B22514A08798E3404DD"
+   "EF9519B3CD3A431B302B0A6DF25F14374FE1356D6D51C245"
+   "E485B576625E7EC6F44C42E9A637ED6B0BFF5CB6F406B7ED"
+   "EE386BFB5A899FA5AE9F24117C4B1FE649286651ECE45B3D"
+   "C2007CB8A163BF0598DA48361C55D39A69163FA8FD24CF5F"
+   "83655D23DCA3AD961C62F356208552BB9ED529077096966D"
+   "670C354E4ABC9804F1746C08CA237327FFFFFFFFFFFFFFFF"
+},
+#endif
+#ifdef LTC_DH2048
+{  /* 2048-bit MODP Group 14 - https://tools.ietf.org/html/rfc3526#section-3 */
+   256,
+   "DH-2048",
+   "2",
+   "FFFFFFFFFFFFFFFFC90FDAA22168C234C4C6628B80DC1CD1"
+   "29024E088A67CC74020BBEA63B139B22514A08798E3404DD"
+   "EF9519B3CD3A431B302B0A6DF25F14374FE1356D6D51C245"
+   "E485B576625E7EC6F44C42E9A637ED6B0BFF5CB6F406B7ED"
+   "EE386BFB5A899FA5AE9F24117C4B1FE649286651ECE45B3D"
+   "C2007CB8A163BF0598DA48361C55D39A69163FA8FD24CF5F"
+   "83655D23DCA3AD961C62F356208552BB9ED529077096966D"
+   "670C354E4ABC9804F1746C08CA18217C32905E462E36CE3B"
+   "E39E772C180E86039B2783A2EC07A28FB5C55DF06F4C52C9"
+   "DE2BCBF6955817183995497CEA956AE515D2261898FA0510"
+   "15728E5A8AACAA68FFFFFFFFFFFFFFFF"
+},
+#endif
+#ifdef LTC_DH3072
+{  /* 3072-bit MODP Group 15 - https://tools.ietf.org/html/rfc3526#section-4 */
+   384,
+   "DH-3072",
+   "2",
+   "FFFFFFFFFFFFFFFFC90FDAA22168C234C4C6628B80DC1CD1"
+   "29024E088A67CC74020BBEA63B139B22514A08798E3404DD"
+   "EF9519B3CD3A431B302B0A6DF25F14374FE1356D6D51C245"
+   "E485B576625E7EC6F44C42E9A637ED6B0BFF5CB6F406B7ED"
+   "EE386BFB5A899FA5AE9F24117C4B1FE649286651ECE45B3D"
+   "C2007CB8A163BF0598DA48361C55D39A69163FA8FD24CF5F"
+   "83655D23DCA3AD961C62F356208552BB9ED529077096966D"
+   "670C354E4ABC9804F1746C08CA18217C32905E462E36CE3B"
+   "E39E772C180E86039B2783A2EC07A28FB5C55DF06F4C52C9"
+   "DE2BCBF6955817183995497CEA956AE515D2261898FA0510"
+   "15728E5A8AAAC42DAD33170D04507A33A85521ABDF1CBA64"
+   "ECFB850458DBEF0A8AEA71575D060C7DB3970F85A6E1E4C7"
+   "ABF5AE8CDB0933D71E8C94E04A25619DCEE3D2261AD2EE6B"
+   "F12FFA06D98A0864D87602733EC86A64521F2B18177B200C"
+   "BBE117577A615D6C770988C0BAD946E208E24FA074E5AB31"
+   "43DB5BFCE0FD108E4B82D120A93AD2CAFFFFFFFFFFFFFFFF"
+},
+#endif
+#ifdef LTC_DH4096
+{  /* 4096-bit MODP Group 16 - https://tools.ietf.org/html/rfc3526#section-5 */
+   512,
+   "DH-4096",
+   "2",
+   "FFFFFFFFFFFFFFFFC90FDAA22168C234C4C6628B80DC1CD1"
+   "29024E088A67CC74020BBEA63B139B22514A08798E3404DD"
+   "EF9519B3CD3A431B302B0A6DF25F14374FE1356D6D51C245"
+   "E485B576625E7EC6F44C42E9A637ED6B0BFF5CB6F406B7ED"
+   "EE386BFB5A899FA5AE9F24117C4B1FE649286651ECE45B3D"
+   "C2007CB8A163BF0598DA48361C55D39A69163FA8FD24CF5F"
+   "83655D23DCA3AD961C62F356208552BB9ED529077096966D"
+   "670C354E4ABC9804F1746C08CA18217C32905E462E36CE3B"
+   "E39E772C180E86039B2783A2EC07A28FB5C55DF06F4C52C9"
+   "DE2BCBF6955817183995497CEA956AE515D2261898FA0510"
+   "15728E5A8AAAC42DAD33170D04507A33A85521ABDF1CBA64"
+   "ECFB850458DBEF0A8AEA71575D060C7DB3970F85A6E1E4C7"
+   "ABF5AE8CDB0933D71E8C94E04A25619DCEE3D2261AD2EE6B"
+   "F12FFA06D98A0864D87602733EC86A64521F2B18177B200C"
+   "BBE117577A615D6C770988C0BAD946E208E24FA074E5AB31"
+   "43DB5BFCE0FD108E4B82D120A92108011A723C12A787E6D7"
+   "88719A10BDBA5B2699C327186AF4E23C1A946834B6150BDA"
+   "2583E9CA2AD44CE8DBBBC2DB04DE8EF92E8EFC141FBECAA6"
+   "287C59474E6BC05D99B2964FA090C3A2233BA186515BE7ED"
+   "1F612970CEE2D7AFB81BDD762170481CD0069127D5B05AA9"
+   "93B4EA988D8FDDC186FFB7DC90A6C08F4DF435C934063199"
+   "FFFFFFFFFFFFFFFF"
+},
+#endif
+#ifdef LTC_DH6144
+{  /* 6144-bit MODP Group 17 - https://tools.ietf.org/html/rfc3526#section-6 */
+   768,
+   "DH-6144",
+   "2",
+   "FFFFFFFFFFFFFFFFC90FDAA22168C234C4C6628B80DC1CD1"
+   "29024E088A67CC74020BBEA63B139B22514A08798E3404DD"
+   "EF9519B3CD3A431B302B0A6DF25F14374FE1356D6D51C245"
+   "E485B576625E7EC6F44C42E9A637ED6B0BFF5CB6F406B7ED"
+   "EE386BFB5A899FA5AE9F24117C4B1FE649286651ECE45B3D"
+   "C2007CB8A163BF0598DA48361C55D39A69163FA8FD24CF5F"
+   "83655D23DCA3AD961C62F356208552BB9ED529077096966D"
+   "670C354E4ABC9804F1746C08CA18217C32905E462E36CE3B"
+   "E39E772C180E86039B2783A2EC07A28FB5C55DF06F4C52C9"
+   "DE2BCBF6955817183995497CEA956AE515D2261898FA0510"
+   "15728E5A8AAAC42DAD33170D04507A33A85521ABDF1CBA64"
+   "ECFB850458DBEF0A8AEA71575D060C7DB3970F85A6E1E4C7"
+   "ABF5AE8CDB0933D71E8C94E04A25619DCEE3D2261AD2EE6B"
+   "F12FFA06D98A0864D87602733EC86A64521F2B18177B200C"
+   "BBE117577A615D6C770988C0BAD946E208E24FA074E5AB31"
+   "43DB5BFCE0FD108E4B82D120A92108011A723C12A787E6D7"
+   "88719A10BDBA5B2699C327186AF4E23C1A946834B6150BDA"
+   "2583E9CA2AD44CE8DBBBC2DB04DE8EF92E8EFC141FBECAA6"
+   "287C59474E6BC05D99B2964FA090C3A2233BA186515BE7ED"
+   "1F612970CEE2D7AFB81BDD762170481CD0069127D5B05AA9"
+   "93B4EA988D8FDDC186FFB7DC90A6C08F4DF435C934028492"
+   "36C3FAB4D27C7026C1D4DCB2602646DEC9751E763DBA37BD"
+   "F8FF9406AD9E530EE5DB382F413001AEB06A53ED9027D831"
+   "179727B0865A8918DA3EDBEBCF9B14ED44CE6CBACED4BB1B"
+   "DB7F1447E6CC254B332051512BD7AF426FB8F401378CD2BF"
+   "5983CA01C64B92ECF032EA15D1721D03F482D7CE6E74FEF6"
+   "D55E702F46980C82B5A84031900B1C9E59E7C97FBEC7E8F3"
+   "23A97A7E36CC88BE0F1D45B7FF585AC54BD407B22B4154AA"
+   "CC8F6D7EBF48E1D814CC5ED20F8037E0A79715EEF29BE328"
+   "06A1D58BB7C5DA76F550AA3D8A1FBFF0EB19CCB1A313D55C"
+   "DA56C9EC2EF29632387FE8D76E3C0468043E8F663F4860EE"
+   "12BF2D5B0B7474D6E694F91E6DCC4024FFFFFFFFFFFFFFFF"
+},
+#endif
+#ifdef LTC_DH8192
+{  /* 8192-bit MODP Group 18 - https://tools.ietf.org/html/rfc3526#section-7 */
+   1024,
+   "DH-8192",
+   "2",
+   "FFFFFFFFFFFFFFFFC90FDAA22168C234C4C6628B80DC1CD1"
+   "29024E088A67CC74020BBEA63B139B22514A08798E3404DD"
+   "EF9519B3CD3A431B302B0A6DF25F14374FE1356D6D51C245"
+   "E485B576625E7EC6F44C42E9A637ED6B0BFF5CB6F406B7ED"
+   "EE386BFB5A899FA5AE9F24117C4B1FE649286651ECE45B3D"
+   "C2007CB8A163BF0598DA48361C55D39A69163FA8FD24CF5F"
+   "83655D23DCA3AD961C62F356208552BB9ED529077096966D"
+   "670C354E4ABC9804F1746C08CA18217C32905E462E36CE3B"
+   "E39E772C180E86039B2783A2EC07A28FB5C55DF06F4C52C9"
+   "DE2BCBF6955817183995497CEA956AE515D2261898FA0510"
+   "15728E5A8AAAC42DAD33170D04507A33A85521ABDF1CBA64"
+   "ECFB850458DBEF0A8AEA71575D060C7DB3970F85A6E1E4C7"
+   "ABF5AE8CDB0933D71E8C94E04A25619DCEE3D2261AD2EE6B"
+   "F12FFA06D98A0864D87602733EC86A64521F2B18177B200C"
+   "BBE117577A615D6C770988C0BAD946E208E24FA074E5AB31"
+   "43DB5BFCE0FD108E4B82D120A92108011A723C12A787E6D7"
+   "88719A10BDBA5B2699C327186AF4E23C1A946834B6150BDA"
+   "2583E9CA2AD44CE8DBBBC2DB04DE8EF92E8EFC141FBECAA6"
+   "287C59474E6BC05D99B2964FA090C3A2233BA186515BE7ED"
+   "1F612970CEE2D7AFB81BDD762170481CD0069127D5B05AA9"
+   "93B4EA988D8FDDC186FFB7DC90A6C08F4DF435C934028492"
+   "36C3FAB4D27C7026C1D4DCB2602646DEC9751E763DBA37BD"
+   "F8FF9406AD9E530EE5DB382F413001AEB06A53ED9027D831"
+   "179727B0865A8918DA3EDBEBCF9B14ED44CE6CBACED4BB1B"
+   "DB7F1447E6CC254B332051512BD7AF426FB8F401378CD2BF"
+   "5983CA01C64B92ECF032EA15D1721D03F482D7CE6E74FEF6"
+   "D55E702F46980C82B5A84031900B1C9E59E7C97FBEC7E8F3"
+   "23A97A7E36CC88BE0F1D45B7FF585AC54BD407B22B4154AA"
+   "CC8F6D7EBF48E1D814CC5ED20F8037E0A79715EEF29BE328"
+   "06A1D58BB7C5DA76F550AA3D8A1FBFF0EB19CCB1A313D55C"
+   "DA56C9EC2EF29632387FE8D76E3C0468043E8F663F4860EE"
+   "12BF2D5B0B7474D6E694F91E6DBE115974A3926F12FEE5E4"
+   "38777CB6A932DF8CD8BEC4D073B931BA3BC832B68D9DD300"
+   "741FA7BF8AFC47ED2576F6936BA424663AAB639C5AE4F568"
+   "3423B4742BF1C978238F16CBE39D652DE3FDB8BEFC848AD9"
+   "22222E04A4037C0713EB57A81A23F0C73473FC646CEA306B"
+   "4BCBC8862F8385DDFA9D4B7FA2C087E879683303ED5BDD3A"
+   "062B3CF5B3A278A66D2A13F83F44F82DDF310EE074AB6A36"
+   "4597E899A0255DC164F31CC50846851DF9AB48195DED7EA1"
+   "B1D510BD7EE74D73FAF36BC31ECFA268359046F4EB879F92"
+   "4009438B481C6CD7889A002ED5EE382BC9190DA6FC026E47"
+   "9558E4475677E9AA9E3050E2765694DFC81F56E880B96E71"
+   "60C980DD98EDD3DFFFFFFFFFFFFFFFFF"
+},
+#endif
+{
+   0,
+   NULL,
+   NULL,
+   NULL
+}
+};
+
+/**
+  Returns the DH group size (octets) for given key
+  @param key   The DH key to get the size of
+  @return The group size in octets (0 on error)
+ */
+int dh_get_groupsize(dh_key *key)
+{
+   if (key == NULL) return 0;
+   return mp_unsigned_bin_size(key->prime);
+}
+
+#endif /* LTC_MDH */
+
+/* ref:         $Format:%D$ */
+/* git commit:  $Format:%H$ */
+/* commit time: $Format:%ai$ */
diff --git a/libtomcrypt/src/pk/dh/dh_check_pubkey.c b/libtomcrypt/src/pk/dh/dh_check_pubkey.c
new file mode 100644
index 0000000..fb4f37b
--- /dev/null
+++ b/libtomcrypt/src/pk/dh/dh_check_pubkey.c
@@ -0,0 +1,65 @@
+/* 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
+
+/**
+  Check DH public key (INTERNAL ONLY, not part of public API)
+  @param key    The key you wish to test
+  @return CRYPT_OK if successful
+*/
+int dh_check_pubkey(dh_key *key)
+{
+   void *p_minus1;
+   ltc_mp_digit digit;
+   int i, digit_count, bits_set = 0, err;
+
+   LTC_ARGCHK(key != NULL);
+
+   if ((err = mp_init(&p_minus1)) != CRYPT_OK) {
+      return err;
+   }
+
+   /* avoid: y <= 1 OR y >= p-1 */
+   if ((err = mp_sub_d(key->prime, 1, p_minus1)) != CRYPT_OK) {
+      goto error;
+   }
+   if (mp_cmp(key->y, p_minus1) != LTC_MP_LT || mp_cmp_d(key->y, 1) != LTC_MP_GT) {
+      err = CRYPT_INVALID_ARG;
+      goto error;
+   }
+
+   /* public key must have more than one bit set */
+   digit_count = mp_get_digit_count(key->y);
+   for (i = 0; i < digit_count && bits_set < 2; i++) {
+      digit = mp_get_digit(key->y, i);
+      while (digit > 0) {
+         if (digit & 1) bits_set++;
+         digit >>= 1;
+      }
+   }
+   if (bits_set > 1) {
+      err = CRYPT_OK;
+   }
+   else {
+      err = CRYPT_INVALID_ARG;
+   }
+
+error:
+   mp_clear(p_minus1);
+   return err;
+}
+
+#endif /* LTC_MDH */
+
+/* ref:         $Format:%D$ */
+/* git commit:  $Format:%H$ */
+/* commit time: $Format:%ai$ */
diff --git a/libtomcrypt/src/pk/dh/dh_export.c b/libtomcrypt/src/pk/dh/dh_export.c
new file mode 100644
index 0000000..6a02a89
--- /dev/null
+++ b/libtomcrypt/src/pk/dh/dh_export.c
@@ -0,0 +1,62 @@
+/* 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
+
+/**
+  Export a DH key to a binary packet
+  @param out    [out] The destination for the key
+  @param outlen [in/out] The max size and resulting size of the DH key
+  @param type   Which type of key (PK_PRIVATE or PK_PUBLIC)
+  @param key    The key you wish to export
+  @return CRYPT_OK if successful
+*/
+int dh_export(unsigned char *out, unsigned long *outlen, int type, dh_key *key)
+{
+   unsigned char flags[1];
+   int err;
+   unsigned long version = 0;
+
+   LTC_ARGCHK(out    != NULL);
+   LTC_ARGCHK(outlen != NULL);
+   LTC_ARGCHK(key    != NULL);
+
+   if (type == PK_PRIVATE) {
+      /* export x - private key */
+      flags[0] = 1;
+      err = der_encode_sequence_multi(out, outlen,
+                                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);
+   }
+   else {
+      /* export y - public key */
+      flags[0] = 0;
+      err = der_encode_sequence_multi(out, outlen,
+                                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);
+   }
+
+   return err;
+}
+
+#endif /* LTC_MDH */
+
+/* ref:         $Format:%D$ */
+/* git commit:  $Format:%H$ */
+/* commit time: $Format:%ai$ */
diff --git a/libtomcrypt/src/pk/dh/dh_export_key.c b/libtomcrypt/src/pk/dh/dh_export_key.c
new file mode 100644
index 0000000..d48c011
--- /dev/null
+++ b/libtomcrypt/src/pk/dh/dh_export_key.c
@@ -0,0 +1,47 @@
+/* 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
+
+/**
+  Binary export a DH key to a buffer
+  @param out    [out] The destination for the key
+  @param outlen [in/out] The max size and resulting size of the DH key
+  @param type   Which type of key (PK_PRIVATE or PK_PUBLIC)
+  @param key    The key you wish to export
+  @return CRYPT_OK if successful
+*/
+int dh_export_key(void *out, unsigned long *outlen, int type, dh_key *key)
+{
+   unsigned long len;
+   void *k;
+
+   LTC_ARGCHK(out    != NULL);
+   LTC_ARGCHK(outlen != NULL);
+   LTC_ARGCHK(key    != NULL);
+
+   k = (type == PK_PRIVATE) ? key->x : key->y;
+   len = mp_unsigned_bin_size(k);
+
+   if (*outlen < len) {
+      *outlen = len;
+      return CRYPT_BUFFER_OVERFLOW;
+   }
+   *outlen = len;
+
+   return mp_to_unsigned_bin(k, out);
+}
+
+#endif /* LTC_MDH */
+
+/* ref:         $Format:%D$ */
+/* git commit:  $Format:%H$ */
+/* commit time: $Format:%ai$ */
diff --git a/libtomcrypt/src/pk/dh/dh_free.c b/libtomcrypt/src/pk/dh/dh_free.c
new file mode 100644
index 0000000..b4f58ca
--- /dev/null
+++ b/libtomcrypt/src/pk/dh/dh_free.c
@@ -0,0 +1,28 @@
+/* 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
+
+/**
+  Free the allocated ram for a DH key
+  @param key   The key which you wish to free
+*/
+void dh_free(dh_key *key)
+{
+   LTC_ARGCHKVD(key != NULL);
+   mp_cleanup_multi(&key->prime, &key->base, &key->y, &key->x, NULL);
+}
+
+#endif /* LTC_MDH */
+
+/* ref:         $Format:%D$ */
+/* git commit:  $Format:%H$ */
+/* commit time: $Format:%ai$ */
diff --git a/libtomcrypt/src/pk/dh/dh_generate_key.c b/libtomcrypt/src/pk/dh/dh_generate_key.c
new file mode 100644
index 0000000..69fb6f9
--- /dev/null
+++ b/libtomcrypt/src/pk/dh/dh_generate_key.c
@@ -0,0 +1,102 @@
+/* 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
+
+static int _dh_groupsize_to_keysize(int groupsize)
+{
+   /* The strength estimates from https://tools.ietf.org/html/rfc3526#section-8
+    * We use "Estimate 2" to get an appropriate private key (exponent) size.
+    */
+   if (groupsize <= 0) {
+      return 0;
+   }
+   else if (groupsize <= 192) {
+      return 30;     /* 1536-bit => key size 240-bit */
+   }
+   else if (groupsize <= 256) {
+      return 40;     /* 2048-bit => key size 320-bit */
+   }
+   else if (groupsize <= 384) {
+      return 52;     /* 3072-bit => key size 416-bit */
+   }
+   else if (groupsize <= 512) {
+      return 60;     /* 4096-bit => key size 480-bit */
+   }
+   else if (groupsize <= 768) {
+      return 67;     /* 6144-bit => key size 536-bit */
+   }
+   else if (groupsize <= 1024) {
+      return 77;     /* 8192-bit => key size 616-bit */
+   }
+   else {
+      return 0;
+   }
+}
+
+int dh_generate_key(prng_state *prng, int wprng, dh_key *key)
+{
+   unsigned char *buf;
+   unsigned long keysize;
+   int err, max_iterations = LTC_PK_MAX_RETRIES;
+
+   LTC_ARGCHK(key         != NULL);
+   LTC_ARGCHK(ltc_mp.name != NULL);
+
+   /* good prng? */
+   if ((err = prng_is_valid(wprng)) != CRYPT_OK) {
+      return err;
+   }
+
+   keysize = _dh_groupsize_to_keysize(mp_unsigned_bin_size(key->prime));
+   if (keysize == 0) {
+      err = CRYPT_INVALID_KEYSIZE;
+      goto freemp;
+   }
+
+   /* allocate buffer */
+   buf = XMALLOC(keysize);
+   if (buf == NULL) {
+      err = CRYPT_MEM;
+      goto freemp;
+   }
+
+   key->type = PK_PRIVATE;
+   do {
+      /* make up random buf */
+      if (prng_descriptor[wprng].read(buf, keysize, prng) != keysize) {
+         err = CRYPT_ERROR_READPRNG;
+         goto freebuf;
+      }
+      /* load the x value - private key */
+      if ((err = mp_read_unsigned_bin(key->x, buf, keysize)) != CRYPT_OK) {
+         goto freebuf;
+      }
+      /* compute the y value - public key */
+      if ((err = mp_exptmod(key->base, key->x, key->prime, key->y)) != CRYPT_OK) {
+         goto freebuf;
+      }
+      err = dh_check_pubkey(key);
+   } while (err != CRYPT_OK && max_iterations-- > 0);
+
+freebuf:
+   zeromem(buf, keysize);
+   XFREE(buf);
+freemp:
+   if (err != CRYPT_OK) dh_free(key);
+   return err;
+}
+
+#endif /* LTC_MDH */
+
+/* ref:         $Format:%D$ */
+/* git commit:  $Format:%H$ */
+/* commit time: $Format:%ai$ */
diff --git a/libtomcrypt/src/pk/dh/dh_import.c b/libtomcrypt/src/pk/dh/dh_import.c
new file mode 100644
index 0000000..601e5e7
--- /dev/null
+++ b/libtomcrypt/src/pk/dh/dh_import.c
@@ -0,0 +1,99 @@
+/* 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: $Format:%ai$ */
diff --git a/libtomcrypt/src/pk/dh/dh_set.c b/libtomcrypt/src/pk/dh/dh_set.c
new file mode 100644
index 0000000..8d0af7d
--- /dev/null
+++ b/libtomcrypt/src/pk/dh/dh_set.c
@@ -0,0 +1,124 @@
+/* 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 DH key parts p and g from raw numbers
+
+  @param p       DH's p (prime)
+  @param plen    DH's p's length
+  @param g       DH's g (group)
+  @param glen    DH's g's length
+  @param key     [out] the destination for the imported key
+  @return CRYPT_OK if successful
+*/
+int dh_set_pg(const unsigned char *p, unsigned long plen,
+              const unsigned char *g, unsigned long glen,
+              dh_key *key)
+{
+   int err;
+
+   LTC_ARGCHK(key         != NULL);
+   LTC_ARGCHK(p           != NULL);
+   LTC_ARGCHK(g           != NULL);
+   LTC_ARGCHK(ltc_mp.name != NULL);
+
+   if ((err = mp_init_multi(&key->x, &key->y, &key->base, &key->prime, NULL)) != CRYPT_OK) {
+      return err;
+   }
+
+   if ((err = mp_read_unsigned_bin(key->base, (unsigned char*)g, glen)) != CRYPT_OK)     { goto LBL_ERR; }
+   if ((err = mp_read_unsigned_bin(key->prime, (unsigned char*)p, plen)) != CRYPT_OK)  { goto LBL_ERR; }
+
+   return CRYPT_OK;
+
+LBL_ERR:
+   dh_free(key);
+   return err;
+}
+
+/**
+  Import DH key parts p and g from built-in DH groups
+
+  @param groupsize  The size of the DH group to use
+  @param key        [out] Where the newly created DH key will be stored
+  @return CRYPT_OK if successful, note: on error all allocated memory will be freed automatically.
+*/
+int dh_set_pg_groupsize(int groupsize, dh_key *key)
+{
+   int err, i;
+
+   LTC_ARGCHK(key         != NULL);
+   LTC_ARGCHK(ltc_mp.name != NULL);
+   LTC_ARGCHK(groupsize   > 0);
+
+   for (i = 0; (groupsize > ltc_dh_sets[i].size) && (ltc_dh_sets[i].size != 0); i++);
+   if (ltc_dh_sets[i].size == 0) return CRYPT_INVALID_KEYSIZE;
+
+   if ((err = mp_init_multi(&key->x, &key->y, &key->base, &key->prime, NULL)) != CRYPT_OK) {
+      return err;
+   }
+   if ((err = mp_read_radix(key->base, ltc_dh_sets[i].base, 16)) != CRYPT_OK)  { goto LBL_ERR; }
+   if ((err = mp_read_radix(key->prime, ltc_dh_sets[i].prime, 16)) != CRYPT_OK) { goto LBL_ERR; }
+
+   return CRYPT_OK;
+
+LBL_ERR:
+   dh_free(key);
+   return err;
+}
+
+/**
+  Import DH public or private key part from raw numbers
+
+     NB: The p & g parts must be set beforehand
+
+  @param in      The key-part to import, either public or private.
+  @param inlen   The key-part's length
+  @param type    Which type of key (PK_PRIVATE or PK_PUBLIC)
+  @param key     [out] the destination for the imported key
+  @return CRYPT_OK if successful
+*/
+int dh_set_key(const unsigned char *in, unsigned long inlen, int type, dh_key *key)
+{
+   int err;
+
+   LTC_ARGCHK(key         != NULL);
+   LTC_ARGCHK(ltc_mp.name != NULL);
+
+   if (type == PK_PRIVATE) {
+      key->type = PK_PRIVATE;
+      if ((err = mp_read_unsigned_bin(key->x, (unsigned char*)in, inlen)) != CRYPT_OK) { goto LBL_ERR; }
+      if ((err = mp_exptmod(key->base, key->x, key->prime, key->y)) != CRYPT_OK)       { goto LBL_ERR; }
+   }
+   else {
+      key->type = PK_PUBLIC;
+      if ((err = mp_read_unsigned_bin(key->y, (unsigned char*)in, inlen)) != CRYPT_OK) { goto LBL_ERR; }
+   }
+
+   /* check public key */
+   if ((err = dh_check_pubkey(key)) != CRYPT_OK) {
+      goto LBL_ERR;
+   }
+
+   return CRYPT_OK;
+
+LBL_ERR:
+   dh_free(key);
+   return err;
+}
+
+#endif /* LTC_MDH */
+
+/* ref:         $Format:%D$ */
+/* git commit:  $Format:%H$ */
+/* commit time: $Format:%ai$ */
diff --git a/libtomcrypt/src/pk/dh/dh_set_pg_dhparam.c b/libtomcrypt/src/pk/dh/dh_set_pg_dhparam.c
new file mode 100644
index 0000000..7003011
--- /dev/null
+++ b/libtomcrypt/src/pk/dh/dh_set_pg_dhparam.c
@@ -0,0 +1,54 @@
+/* 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 DH key parts p and g from dhparam
+
+      dhparam data: openssl dhparam -outform DER -out dhparam.der 2048
+
+  @param dhparam    The DH param DER encoded data
+  @param dhparamlen The length of dhparam data
+  @param key        [out] Where the newly created DH key will be stored
+  @return CRYPT_OK if successful, note: on error all allocated memory will be freed automatically.
+*/
+int dh_set_pg_dhparam(const unsigned char *dhparam, unsigned long dhparamlen, dh_key *key)
+{
+   int err;
+
+   LTC_ARGCHK(key         != NULL);
+   LTC_ARGCHK(ltc_mp.name != NULL);
+   LTC_ARGCHK(dhparam     != NULL);
+   LTC_ARGCHK(dhparamlen  > 0);
+
+   if ((err = mp_init_multi(&key->x, &key->y, &key->base, &key->prime, NULL)) != CRYPT_OK) {
+      return err;
+   }
+   if ((err = der_decode_sequence_multi(dhparam, dhparamlen,
+                                        LTC_ASN1_INTEGER, 1UL, key->prime,
+                                        LTC_ASN1_INTEGER, 1UL, key->base,
+                                        LTC_ASN1_EOL,     0UL, NULL)) != CRYPT_OK) {
+      goto LBL_ERR;
+   }
+
+   return CRYPT_OK;
+
+LBL_ERR:
+   dh_free(key);
+   return err;
+}
+
+#endif /* LTC_MDH */
+
+/* ref:         $Format:%D$ */
+/* git commit:  $Format:%H$ */
+/* commit time: $Format:%ai$ */
diff --git a/libtomcrypt/src/pk/dh/dh_shared_secret.c b/libtomcrypt/src/pk/dh/dh_shared_secret.c
new file mode 100644
index 0000000..1eb69fb
--- /dev/null
+++ b/libtomcrypt/src/pk/dh/dh_shared_secret.c
@@ -0,0 +1,80 @@
+/* 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
+
+/**
+   Create a DH shared secret.
+   @param private_key     The private DH key in the pair
+   @param public_key      The public DH key in the pair
+   @param out             [out] The destination of the shared data
+   @param outlen          [in/out] The max size and resulting size of the shared data.
+   @return CRYPT_OK if successful
+*/
+int dh_shared_secret(dh_key *private_key, dh_key *public_key,
+                     unsigned char *out, unsigned long *outlen)
+{
+   void *tmp;
+   unsigned long x;
+   int err;
+
+   LTC_ARGCHK(private_key != NULL);
+   LTC_ARGCHK(public_key  != NULL);
+   LTC_ARGCHK(out         != NULL);
+   LTC_ARGCHK(outlen      != NULL);
+
+   /* types valid? */
+   if (private_key->type != PK_PRIVATE) {
+      return CRYPT_PK_NOT_PRIVATE;
+   }
+
+   /* same DH group? */
+   if (mp_cmp(private_key->prime, public_key->prime) != LTC_MP_EQ) { return CRYPT_PK_TYPE_MISMATCH; }
+   if (mp_cmp(private_key->base, public_key->base) != LTC_MP_EQ)   { return CRYPT_PK_TYPE_MISMATCH; }
+
+   /* init big numbers */
+   if ((err = mp_init(&tmp)) != CRYPT_OK) {
+      return err;
+   }
+
+   /* check public key */
+   if ((err = dh_check_pubkey(public_key)) != CRYPT_OK) {
+      goto error;
+   }
+
+   /* compute tmp = y^x mod p */
+   if ((err = mp_exptmod(public_key->y, private_key->x, private_key->prime, tmp)) != CRYPT_OK)  {
+      goto error;
+   }
+
+   /* enough space for output? */
+   x = (unsigned long)mp_unsigned_bin_size(tmp);
+   if (*outlen < x) {
+      *outlen = x;
+      err = CRYPT_BUFFER_OVERFLOW;
+      goto error;
+   }
+   if ((err = mp_to_unsigned_bin(tmp, out)) != CRYPT_OK) {
+      goto error;
+   }
+   *outlen = x;
+   err = CRYPT_OK;
+
+error:
+   mp_clear(tmp);
+   return err;
+}
+
+#endif /* LTC_MDH */
+
+/* ref:         $Format:%D$ */
+/* git commit:  $Format:%H$ */
+/* commit time: $Format:%ai$ */