Added a bignum library to abstract possible implementations.

14 files changed, 208 insertions, 42 deletions

diff --git a/CMakeLists.txt b/CMakeLists.txt
index a27da23..7e285f6 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -22,6 +22,7 @@ if(DOXYGEN_FOUND)
 	)
 endif(DOXYGEN_FOUND)
 
+add_subdirectory(libcmix-bignum)
 add_subdirectory(libcmix-crypto)
 add_subdirectory(libcmix)
 
diff --git a/CMakeModules/bignum_implementations.cmake b/CMakeModules/bignum_implementations.cmake
new file mode 100644
index 0000000..4db7d78
--- /dev/null
+++ b/CMakeModules/bignum_implementations.cmake
@@ -0,0 +1,3 @@
+include(implementations)
+
+DefineImplementations("")
diff --git a/CMakeModules/get_target_name.cmake b/CMakeModules/get_target_name.cmake
index 6e7c6fd..90d585d 100644
--- a/CMakeModules/get_target_name.cmake
+++ b/CMakeModules/get_target_name.cmake
@@ -1,10 +1,10 @@
 
 function(get_target_name target_name)
 
-get_filename_component(implementation ${CMAKE_CURRENT_LIST_DIR} NAME)
-get_filename_component(implementation_path ${CMAKE_CURRENT_LIST_DIR} DIRECTORY)
-get_filename_component(algorithm ${implementation_path} NAME)
+	get_filename_component(implementation ${CMAKE_CURRENT_LIST_DIR} NAME)
+	get_filename_component(implementation_path ${CMAKE_CURRENT_LIST_DIR} DIRECTORY)
+	get_filename_component(algorithm ${implementation_path} NAME)
 
-set(${target_name} "${algorithm}-${implementation}" PARENT_SCOPE)
+	set(${target_name} "${algorithm}-${implementation}" PARENT_SCOPE)
 
 endfunction(get_target_name)
diff --git a/CMakeModules/implementations.cmake b/CMakeModules/implementations.cmake
index aa6a8bf..cfab7e2 100644
--- a/CMakeModules/implementations.cmake
+++ b/CMakeModules/implementations.cmake
@@ -5,7 +5,7 @@ function(DefineImplementations prefix)
 	set(implementations "")
 	foreach(child ${children})
 		IF(IS_DIRECTORY ${CMAKE_CURRENT_SOURCE_DIR}/${prefix}/${child})
-		    LIST(APPEND implementations ${child})
+			LIST(APPEND implementations ${child})
 		ENDIF()
 	ENDFOREACH()
 
@@ -15,9 +15,21 @@ function(DefineImplementations prefix)
 		message(FATAL_ERROR "Cannot call DefineImplementations with an empty implementations list.")
 	endif()
 
+	get_filename_component(lib ${CMAKE_CURRENT_SOURCE_DIR} NAME)
+	string(REGEX REPLACE "-" "_" lib ${lib})
+
 	list(GET implementations 0 default)
-	set(${prefix}_implementations ${implementations} PARENT_SCOPE)
-	set(${prefix}_implementation "${default}" CACHE STRING "${prefix} implementation chosen at configure time")
-	set_property(CACHE ${prefix}_implementation PROPERTY STRINGS ${implementations})
+	
+	if ("${prefix}" STREQUAL "")
+		set(prefix "")
+	else()
+		set(prefix "${prefix}_")
+		string(REGEX REPLACE "/" "_" prefix ${prefix})
+	endif()
+	
+	
+	set(${lib}_${prefix}implementations ${implementations} PARENT_SCOPE)
+	set(${lib}_${prefix}implementation "${default}" CACHE STRING "${lib} implementation chosen at configure time")
+	set_property(CACHE ${lib}_${prefix}implementation PROPERTY STRINGS ${implementations})
 
 endfunction(DefineImplementations)
diff --git a/libcmix-bignum/CMakeLists.txt b/libcmix-bignum/CMakeLists.txt
new file mode 100644
index 0000000..2cadc87
--- /dev/null
+++ b/libcmix-bignum/CMakeLists.txt
@@ -0,0 +1,33 @@
+
+add_library(cmix-bignum-interface INTERFACE)
+
+target_include_directories(cmix-bignum-interface
+	INTERFACE ${CMAKE_CURRENT_SOURCE_DIR}
+)
+
+set(interface_sources 
+	${CMAKE_CURRENT_SOURCE_DIR}/bignum.h
+)
+
+target_sources(cmix-bignum-interface
+	INTERFACE ${interface_sources}
+)
+
+include(bignum_implementations)
+foreach(impl ${libcmix_bignum_implementations})
+	add_subdirectory(${impl})
+endforeach()
+
+add_library(cmix-bignum INTERFACE)
+
+target_include_directories(cmix-bignum
+	INTERFACE ${CMAKE_CURRENT_SOURCE_DIR}
+)
+
+target_sources(cmix-bignum
+	INTERFACE ${interface_sources}
+)
+
+target_link_libraries(cmix-bignum
+	INTERFACE libcmix-bignum-${libcmix_bignum_implementation}
+)
diff --git a/libcmix-bignum/bignum.h b/libcmix-bignum/bignum.h
new file mode 100644
index 0000000..02efcf7
--- /dev/null
+++ b/libcmix-bignum/bignum.h
@@ -0,0 +1,40 @@
+#pragma once
+
+#include <stddef.h>
+#include <stdlib.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+enum bignum_error {
+	NoError = 0,
+	error = -1
+};
+
+struct Bignum {
+	unsigned char* data;
+	size_t len;
+};
+
+struct Bignum allocate_bignum(size_t len) {
+	return (struct Bignum){
+		(unsigned char*) malloc(len),
+		len
+	};
+}
+
+void free_bignum(struct Bignum* b) {
+	free(b->data);
+	b->data = 0;
+	b->len = 0;
+}
+
+extern enum bignum_error get_curve25519_mod(struct Bignum* result);
+
+extern enum bignum_error multiply_mod(struct Bignum* result, struct Bignum const lh, struct Bignum const rh, struct Bignum const mod);
+
+
+#ifdef __cplusplus
+}
+#endif
\ No newline at end of file
diff --git a/libcmix-bignum/gmp/CMakeLists.txt b/libcmix-bignum/gmp/CMakeLists.txt
new file mode 100644
index 0000000..44b99ad
--- /dev/null
+++ b/libcmix-bignum/gmp/CMakeLists.txt
@@ -0,0 +1,18 @@
+include(get_target_name)
+
+get_target_name(target_name)
+
+find_package(gmp REQUIRED)
+
+add_library(${target_name} SHARED
+	gmp_bignum.c
+)
+
+target_compile_options(${target_name}
+	PRIVATE -std=c99
+)
+
+target_link_libraries(${target_name}
+	PRIVATE cmix-bignum-interface
+	PRIVATE gmp
+)
diff --git a/libcmix-bignum/gmp/gmp_bignum.c b/libcmix-bignum/gmp/gmp_bignum.c
new file mode 100644
index 0000000..cc40b48
--- /dev/null
+++ b/libcmix-bignum/gmp/gmp_bignum.c
@@ -0,0 +1,49 @@
+#include "bignum.h"
+
+#include "gmp.h"
+
+void from_bignum(mpz_t i, struct Bignum b) {	
+	mpz_import(i, b.len, -1, 1, 0, 0, b.data);
+}
+
+void to_bignum(struct Bignum* b, mpz_t i) {
+	mpz_export(b->data, &b->len, -1, 1, 0, 0, i);
+}
+
+enum bignum_error get_curve25519_mod(struct Bignum* result) {
+	mpz_t mod;
+	mpz_init(mod);
+	mpz_ui_pow_ui(mod, 2, 255);
+	mpz_sub_ui(mod, mod, 19);
+	
+	to_bignum(result, mod);
+	return NoError;
+}
+
+enum bignum_error multiply_mod(struct Bignum* result, struct Bignum const lh, struct Bignum const rh, struct Bignum const mod) {
+	mpz_t lh_;
+	mpz_init(lh_);
+	from_bignum(lh_, lh);
+	
+	mpz_t rh_;
+	mpz_init(rh_);
+	from_bignum(rh_, rh);
+	
+	mpz_t result_;
+	mpz_init(result_);
+	mpz_mul(result_, lh_, rh_);
+	
+	mpz_t mod_;
+	mpz_init(mod_);
+	from_bignum(mod_, mod);
+	mpz_mod(result_, result_, mod_);
+	
+	to_bignum(result, result_);
+	
+	mpz_clear(result_);
+	mpz_clear(lh_);
+	mpz_clear(rh_);
+	mpz_clear(mod_);
+	
+	return NoError;
+}
diff --git a/libcmix-bignum/null/CMakeLists.txt b/libcmix-bignum/null/CMakeLists.txt
new file mode 100644
index 0000000..319590c
--- /dev/null
+++ b/libcmix-bignum/null/CMakeLists.txt
@@ -0,0 +1,15 @@
+include(get_target_name)
+
+get_target_name(target_name)
+
+add_library(${target_name} SHARED
+	null_bignum.c
+)
+
+target_compile_options(${target_name}
+	PRIVATE -std=c99
+)
+
+target_link_libraries(${target_name}
+	PRIVATE cmix-bignum-interface
+)
diff --git a/libcmix-bignum/null/null_bignum.c b/libcmix-bignum/null/null_bignum.c
new file mode 100644
index 0000000..3b45132
--- /dev/null
+++ b/libcmix-bignum/null/null_bignum.c
@@ -0,0 +1,9 @@
+#include "bignum.h"
+
+extern enum bignum_error get_curve25519_mod(struct Bignum* result) {
+	return NoError;
+}
+
+extern enum bignum_error multiply_mod(struct Bignum* result, struct Bignum const lh, struct Bignum const rh, struct Bignum const mod) {
+	return NoError;
+}
diff --git a/libcmix-crypto/curve25519/CMakeLists.txt b/libcmix-crypto/curve25519/CMakeLists.txt
index afcc1b4..847c26c 100644
--- a/libcmix-crypto/curve25519/CMakeLists.txt
+++ b/libcmix-crypto/curve25519/CMakeLists.txt
@@ -1,4 +1,3 @@
-
 add_library(curve25519-interface INTERFACE)
 
 target_include_directories(curve25519-interface
@@ -13,7 +12,7 @@ target_link_libraries(curve25519-interface
 	INTERFACE cmix-crypto-interface
 )
 
-foreach(impl ${curve25519_implementations})
+foreach(impl ${libcmix_crypto_curve25519_implementations})
 	add_subdirectory(${impl})
 endforeach()
 
@@ -27,7 +26,7 @@ target_include_directories(curve25519-implementation
 
 target_link_libraries(curve25519-implementation
 	PUBLIC curve25519-interface
-	PUBLIC curve25519-${curve25519_implementation}
+	PUBLIC curve25519-${libcmix_crypto_curve25519_implementation}
 )
 
 
diff --git a/libcmix-crypto/elgamal/CMakeLists.txt b/libcmix-crypto/elgamal/CMakeLists.txt
index b92e5ae..8ee9a11 100644
--- a/libcmix-crypto/elgamal/CMakeLists.txt
+++ b/libcmix-crypto/elgamal/CMakeLists.txt
@@ -12,7 +12,7 @@ target_link_libraries(elgamal-interface
 	INTERFACE cmix-crypto-interface
 )
 
-foreach(impl ${elgamal_implementations})
+foreach(impl ${libcmix_crypto_elgamal_implementations})
 	add_subdirectory(${impl})
 endforeach()
 
@@ -26,5 +26,5 @@ target_include_directories(elgamal-implementation
 
 target_link_libraries(elgamal-implementation
 	PUBLIC elgamal-interface
-	PUBLIC elgamal-${elgamal_implementation}
+	PUBLIC elgamal-${libcmix_crypto_elgamal_implementation}
 )
diff --git a/node/CMakeLists.txt b/node/CMakeLists.txt
index 6fe0ef7..9151cbc 100644
--- a/node/CMakeLists.txt
+++ b/node/CMakeLists.txt
@@ -1,7 +1,5 @@
 find_package(Boost COMPONENTS system program_options REQUIRED)
 
-find_package(gmp REQUIRED)
-
 add_executable(node
 	main.cpp
 	node.hpp node.cpp
@@ -25,8 +23,7 @@ target_link_libraries(node
 	PRIVATE Boost::system
 	PRIVATE log
 	PRIVATE cmix
+	PRIVATE cmix-bignum
 	PRIVATE cmix-network
 	PRIVATE cmix-protobuf
-	PRIVATE gmpxx
-	PRIVATE gmp
 )
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);
 	}
 }