From 4f2c980343b321e7fccf48190c32bfb4bca426f4 Mon Sep 17 00:00:00 2001
From: Dennis Brentjes <d.brentjes@gmail.com>
Date: Tue, 4 Oct 2016 12:18:35 +0200
Subject: Added a bignum library to abstract possible implementations.

---
 node/node.cpp | 40 +++++++++++++++-------------------------
 1 file changed, 15 insertions(+), 25 deletions(-)

(limited to 'node/node.cpp')

diff --git a/node/node.cpp b/node/node.cpp
index 53dd30c..c9f6b14 100644
--- a/node/node.cpp
+++ b/node/node.cpp
@@ -2,7 +2,7 @@
 
 #include "logging.hpp"
 
-#include "gmpxx.h"
+#include "bignum.h"
 
 #include <iostream>
 
@@ -87,36 +87,26 @@ void Node::handle_initialization(const cmix_proto::Initialization& init)
 					
 		start_precomputation();
 	} else {
-		mpz_t shared;
-		mpz_init(shared);
-		mpz_import(shared, init.public_share().size(), -1, 1, 0, 0, init.public_share().data());
+		Bignum shared = allocate_bignum(init.public_share().size());
+		std::copy_n(init.public_share().data(), init.public_share().size(), shared.data);
+		Bignum my_share{keypair.pub, keypair.pub_len};
+		Bignum mod = allocate_bignum(keypair.pub_len);
+		Bignum new_shared = allocate_bignum(keypair.pub_len);
 		
-		mpz_t my_share;
-		mpz_init(my_share);
-		mpz_import(my_share, keypair.pub_len, -1, 1, 0, 0, keypair.pub);
-		
-		mpz_mul(shared, shared, my_share);
-		
-		mpz_t mod;
-		mpz_init(mod);
-		mpz_set_ui(mod, 2);
-		mpz_pow_ui(mod, mod, 255);
-		mpz_sub_ui(mod, mod, 19);
-		
-		mpz_mod(shared, shared, mod);
-		
-		std::vector<uint8_t> new_shared(keypair.pub_len, '\0');
-		size_t size;
-		mpz_export(new_shared.data(), &size, -1, 1, 0, 0, shared);
+		if(multiply_mod(&new_shared, shared, my_share, mod) != NoError) {
+			BOOST_LOG_TRIVIAL(fatal) << "Group multiplication failed";
+			throw std::runtime_error("Group multiplication failed");
+		}
 		
 		cmix_proto::Initialization init;
-		init.set_public_share(new_shared.data(), new_shared.size());
+		init.set_public_share(new_shared.data, new_shared.len);
 		
 		next_node.send(init);
+	
+		free_bignum(&shared);
+		free_bignum(&mod);
+		free_bignum(&new_shared);
 		
-		mpz_clear(shared);
-		mpz_clear(my_share);
-		mpz_clear(mod);
 	}
 }
 
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