1 files changed, 333 insertions, 0 deletions
diff --git a/botan/src/pubkey/dl_group/dl_group.cpp b/botan/src/pubkey/dl_group/dl_group.cpp
new file mode 100644
index 0000000..81c5d5e
--- /dev/null
+++ b/botan/src/pubkey/dl_group/dl_group.cpp
@@ -0,0 +1,333 @@
+/*
+* Discrete Logarithm Parameters
+* (C) 1999-2008 Jack Lloyd
+*
+* Distributed under the terms of the Botan license
+*/
+
+#include <botan/dl_group.h>
+#include <botan/libstate.h>
+#include <botan/parsing.h>
+#include <botan/numthry.h>
+#include <botan/der_enc.h>
+#include <botan/ber_dec.h>
+#include <botan/pipe.h>
+#include <botan/util.h>
+#include <botan/pem.h>
+
+namespace Botan {
+
+/*
+* DL_Group Constructor
+*/
+DL_Group::DL_Group()
+   {
+   initialized = false;
+   }
+
+/*
+* DL_Group Constructor
+*/
+DL_Group::DL_Group(const std::string& type)
+   {
+   std::string grp_contents = global_state().get("dl", type);
+
+   if(grp_contents == "")
+      throw Invalid_Argument("DL_Group: Unknown group " + type);
+
+   DataSource_Memory pem(grp_contents);
+   PEM_decode(pem);
+   }
+
+/*
+* DL_Group Constructor
+*/
+DL_Group::DL_Group(RandomNumberGenerator& rng,
+                   PrimeType type, u32bit pbits, u32bit qbits)
+   {
+   if(pbits < 512)
+      throw Invalid_Argument("DL_Group: prime size " + to_string(pbits) +
+                             " is too small");
+
+   if(type == Strong)
+      {
+      p = random_safe_prime(rng, pbits);
+      q = (p - 1) / 2;
+      g = 2;
+      }
+   else if(type == Prime_Subgroup || type == DSA_Kosherizer)
+      {
+      if(type == Prime_Subgroup)
+         {
+         if(!qbits)
+            qbits = 2 * dl_work_factor(pbits);
+
+         q = random_prime(rng, qbits);
+         BigInt X;
+         while(p.bits() != pbits || !is_prime(p, rng))
+            {
+            X.randomize(rng, pbits);
+            p = X - (X % (2*q) - 1);
+            }
+         }
+      else
+         {
+         qbits = qbits ? qbits : ((pbits == 1024) ? 160 : 256);
+         generate_dsa_primes(rng,
+                             global_state().algorithm_factory(),
+                             p, q, pbits, qbits);
+         }
+
+      g = make_dsa_generator(p, q);
+      }
+
+   initialized = true;
+   }
+
+/*
+* DL_Group Constructor
+*/
+DL_Group::DL_Group(RandomNumberGenerator& rng,
+                   const MemoryRegion<byte>& seed, u32bit pbits, u32bit qbits)
+   {
+   if(!generate_dsa_primes(rng,
+                           global_state().algorithm_factory(),
+                           p, q, pbits, qbits, seed))
+      throw Invalid_Argument("DL_Group: The seed given does not "
+                             "generate a DSA group");
+
+   g = make_dsa_generator(p, q);
+
+   initialized = true;
+   }
+
+/*
+* DL_Group Constructor
+*/
+DL_Group::DL_Group(const BigInt& p1, const BigInt& g1)
+   {
+   initialize(p1, 0, g1);
+   }
+
+/*
+* DL_Group Constructor
+*/
+DL_Group::DL_Group(const BigInt& p1, const BigInt& q1, const BigInt& g1)
+   {
+   initialize(p1, q1, g1);
+   }
+
+/*
+* DL_Group Initializer
+*/
+void DL_Group::initialize(const BigInt& p1, const BigInt& q1, const BigInt& g1)
+   {
+   if(p1 < 3)
+      throw Invalid_Argument("DL_Group: Prime invalid");
+   if(g1 < 2 || g1 >= p1)
+      throw Invalid_Argument("DL_Group: Generator invalid");
+   if(q1 < 0 || q1 >= p1)
+      throw Invalid_Argument("DL_Group: Subgroup invalid");
+
+   p = p1;
+   g = g1;
+   q = q1;
+
+   initialized = true;
+   }
+
+/*
+* Verify that the group has been set
+*/
+void DL_Group::init_check() const
+   {
+   if(!initialized)
+      throw Invalid_State("DLP group cannot be used uninitialized");
+   }
+
+/*
+* Verify the parameters
+*/
+bool DL_Group::verify_group(RandomNumberGenerator& rng,
+                            bool strong) const
+   {
+   init_check();
+
+   if(g < 2 || p < 3 || q < 0)
+      return false;
+   if((q != 0) && ((p - 1) % q != 0))
+      return false;
+
+   if(!strong)
+      return true;
+
+   if(!check_prime(p, rng))
+      return false;
+   if((q > 0) && !check_prime(q, rng))
+      return false;
+   return true;
+   }
+
+/*
+* Return the prime
+*/
+const BigInt& DL_Group::get_p() const
+   {
+   init_check();
+   return p;
+   }
+
+/*
+* Return the generator
+*/
+const BigInt& DL_Group::get_g() const
+   {
+   init_check();
+   return g;
+   }
+
+/*
+* Return the subgroup
+*/
+const BigInt& DL_Group::get_q() const
+   {
+   init_check();
+   if(q == 0)
+      throw Format_Error("DLP group has no q prime specified");
+   return q;
+   }
+
+/*
+* DER encode the parameters
+*/
+SecureVector<byte> DL_Group::DER_encode(Format format) const
+   {
+   init_check();
+
+   if((q == 0) && (format != PKCS_3))
+      throw Encoding_Error("The ANSI DL parameter formats require a subgroup");
+
+   if(format == ANSI_X9_57)
+      {
+      return DER_Encoder()
+         .start_cons(SEQUENCE)
+            .encode(p)
+            .encode(q)
+            .encode(g)
+         .end_cons()
+      .get_contents();
+      }
+   else if(format == ANSI_X9_42)
+      {
+      return DER_Encoder()
+         .start_cons(SEQUENCE)
+            .encode(p)
+            .encode(g)
+            .encode(q)
+         .end_cons()
+      .get_contents();
+      }
+   else if(format == PKCS_3)
+      {
+      return DER_Encoder()
+         .start_cons(SEQUENCE)
+            .encode(p)
+            .encode(g)
+         .end_cons()
+      .get_contents();
+      }
+
+   throw Invalid_Argument("Unknown DL_Group encoding " + to_string(format));
+   }
+
+/*
+* PEM encode the parameters
+*/
+std::string DL_Group::PEM_encode(Format format) const
+   {
+   SecureVector<byte> encoding = DER_encode(format);
+   if(format == PKCS_3)
+      return PEM_Code::encode(encoding, "DH PARAMETERS");
+   else if(format == ANSI_X9_57)
+      return PEM_Code::encode(encoding, "DSA PARAMETERS");
+   else if(format == ANSI_X9_42)
+      return PEM_Code::encode(encoding, "X942 DH PARAMETERS");
+   else
+      throw Invalid_Argument("Unknown DL_Group encoding " + to_string(format));
+   }
+
+/*
+* Decode BER encoded parameters
+*/
+void DL_Group::BER_decode(DataSource& source, Format format)
+   {
+   BigInt new_p, new_q, new_g;
+
+   BER_Decoder decoder(source);
+   BER_Decoder ber = decoder.start_cons(SEQUENCE);
+
+   if(format == ANSI_X9_57)
+      {
+      ber.decode(new_p)
+         .decode(new_q)
+         .decode(new_g)
+         .verify_end();
+      }
+   else if(format == ANSI_X9_42)
+      {
+      ber.decode(new_p)
+         .decode(new_g)
+         .decode(new_q)
+         .discard_remaining();
+      }
+   else if(format == PKCS_3)
+      {
+      ber.decode(new_p)
+         .decode(new_g)
+         .discard_remaining();
+      }
+   else
+      throw Invalid_Argument("Unknown DL_Group encoding " + to_string(format));
+
+   initialize(new_p, new_q, new_g);
+   }
+
+/*
+* Decode PEM encoded parameters
+*/
+void DL_Group::PEM_decode(DataSource& source)
+   {
+   std::string label;
+   DataSource_Memory ber(PEM_Code::decode(source, label));
+
+   if(label == "DH PARAMETERS")
+      BER_decode(ber, PKCS_3);
+   else if(label == "DSA PARAMETERS")
+      BER_decode(ber, ANSI_X9_57);
+   else if(label == "X942 DH PARAMETERS")
+      BER_decode(ber, ANSI_X9_42);
+   else
+      throw Decoding_Error("DL_Group: Invalid PEM label " + label);
+   }
+
+/*
+* Create a random DSA-style generator
+*/
+BigInt DL_Group::make_dsa_generator(const BigInt& p, const BigInt& q)
+   {
+   BigInt g, e = (p - 1) / q;
+
+   for(u32bit j = 0; j != PRIME_TABLE_SIZE; ++j)
+      {
+      g = power_mod(PRIMES[j], e, p);
+      if(g != 1)
+         break;
+      }
+
+   if(g == 1)
+      throw Exception("DL_Group: Couldn't create a suitable generator");
+
+   return g;
+   }
+
+}