1 files changed, 134 insertions, 0 deletions
diff --git a/src/lib/pubkey/ec_group/ec_group.cpp b/src/lib/pubkey/ec_group/ec_group.cpp
new file mode 100644
index 000000000..9143543e4
--- /dev/null
+++ b/src/lib/pubkey/ec_group/ec_group.cpp
@@ -0,0 +1,134 @@
+/*
+* ECC Domain Parameters
+*
+* (C) 2007 Falko Strenzke, FlexSecure GmbH
+*     2008 Jack Lloyd
+*
+* Distributed under the terms of the Botan license
+*/
+
+#include <botan/ec_group.h>
+#include <botan/ber_dec.h>
+#include <botan/der_enc.h>
+#include <botan/libstate.h>
+#include <botan/oids.h>
+#include <botan/pem.h>
+
+namespace Botan {
+
+EC_Group::EC_Group(const OID& domain_oid)
+   {
+   const char* pem = PEM_for_named_group(OIDS::lookup(domain_oid));
+
+   if(!pem)
+      throw Lookup_Error("No ECC domain data for " + domain_oid.as_string());
+
+   *this = EC_Group(pem);
+   oid = domain_oid.as_string();
+   }
+
+EC_Group::EC_Group(const std::string& str)
+   {
+   if(str == "")
+      return; // no initialization / uninitialized
+
+   try
+      {
+      std::vector<byte> ber =
+         unlock(PEM_Code::decode_check_label(str, "EC PARAMETERS"));
+
+      *this = EC_Group(ber);
+      }
+   catch(Decoding_Error) // hmm, not PEM?
+      {
+      *this = EC_Group(OIDS::lookup(str));
+      }
+   }
+
+EC_Group::EC_Group(const std::vector<byte>& ber_data)
+   {
+   BER_Decoder ber(ber_data);
+   BER_Object obj = ber.get_next_object();
+
+   if(obj.type_tag == NULL_TAG)
+      throw Decoding_Error("Cannot handle ImplicitCA ECDSA parameters");
+   else if(obj.type_tag == OBJECT_ID)
+      {
+      OID dom_par_oid;
+      BER_Decoder(ber_data).decode(dom_par_oid);
+      *this = EC_Group(dom_par_oid);
+      }
+   else if(obj.type_tag == SEQUENCE)
+      {
+      BigInt p, a, b;
+      std::vector<byte> sv_base_point;
+
+      BER_Decoder(ber_data)
+         .start_cons(SEQUENCE)
+           .decode_and_check<size_t>(1, "Unknown ECC param version code")
+           .start_cons(SEQUENCE)
+            .decode_and_check(OID("1.2.840.10045.1.1"),
+                              "Only prime ECC fields supported")
+             .decode(p)
+           .end_cons()
+           .start_cons(SEQUENCE)
+             .decode_octet_string_bigint(a)
+             .decode_octet_string_bigint(b)
+           .end_cons()
+           .decode(sv_base_point, OCTET_STRING)
+           .decode(order)
+           .decode(cofactor)
+         .end_cons()
+         .verify_end();
+
+      curve = CurveGFp(p, a, b);
+      base_point = OS2ECP(sv_base_point, curve);
+      }
+   else
+      throw Decoding_Error("Unexpected tag while decoding ECC domain params");
+   }
+
+std::vector<byte>
+EC_Group::DER_encode(EC_Group_Encoding form) const
+   {
+   if(form == EC_DOMPAR_ENC_EXPLICIT)
+      {
+      const size_t ecpVers1 = 1;
+      OID curve_type("1.2.840.10045.1.1");
+
+      const size_t p_bytes = curve.get_p().bytes();
+
+      return DER_Encoder()
+         .start_cons(SEQUENCE)
+            .encode(ecpVers1)
+            .start_cons(SEQUENCE)
+               .encode(curve_type)
+               .encode(curve.get_p())
+            .end_cons()
+            .start_cons(SEQUENCE)
+               .encode(BigInt::encode_1363(curve.get_a(), p_bytes),
+                       OCTET_STRING)
+               .encode(BigInt::encode_1363(curve.get_b(), p_bytes),
+                       OCTET_STRING)
+            .end_cons()
+            .encode(EC2OSP(base_point, PointGFp::UNCOMPRESSED), OCTET_STRING)
+            .encode(order)
+            .encode(cofactor)
+         .end_cons()
+         .get_contents_unlocked();
+      }
+   else if(form == EC_DOMPAR_ENC_OID)
+      return DER_Encoder().encode(OID(get_oid())).get_contents_unlocked();
+   else if(form == EC_DOMPAR_ENC_IMPLICITCA)
+      return DER_Encoder().encode_null().get_contents_unlocked();
+   else
+      throw Internal_Error("EC_Group::DER_encode: Unknown encoding");
+   }
+
+std::string EC_Group::PEM_encode() const
+   {
+   const std::vector<byte> der = DER_encode(EC_DOMPAR_ENC_EXPLICIT);
+   return PEM_Code::encode(der, "EC PARAMETERS");
+   }
+
+}