prepares the api for sending and mixing messages in the realtime phase.

1 files changed, 34 insertions, 7 deletions

diff --git a/libcmix/cmix.c b/libcmix/cmix.c
index 28f56db..582fe70 100644
--- a/libcmix/cmix.c
+++ b/libcmix/cmix.c
@@ -45,7 +45,8 @@ struct CMixContext initialize_cmix_context(struct Api api) {
 		.r = NULL,
 		.s = NULL,
 		.permutation = NULL,
-		.pirs = NULL
+		.pirs = NULL,
+		.messages = NULL
 	};
 }
 
@@ -54,17 +55,20 @@ void release_mix(struct CMixContext* ctx) {
 		ctx->api.free_group_element(ctx->r[i]);
 		ctx->api.free_group_element(ctx->s[i]);
 		ctx->api.free_group_element(ctx->pirs[i]);
+		ctx->api.free_group_element(ctx->messages[i]);
 	}
 	free(ctx->r);
 	free(ctx->s);
 	free(ctx->permutation);
 	free(ctx->pirs);
+	free(ctx->messages);
 }
 
 void deinitialize(struct CMixContext* ctx)
 {
 	ctx->api.free_keypair(&ctx->keypair);
 	release_mix(ctx);
+	ctx->api.deinitialize();
 }
 
 void element_to_buffer(struct CMixContext const* ctx, char* out_buffer, GroupElement element) {
@@ -106,7 +110,8 @@ enum cmix_error alloc_mix(struct CMixContext* ctx) {
 	ctx->s = (GroupElement*) calloc(ctx->nr_participants, sizeof(GroupElement));
 	ctx->permutation = (unsigned int*) calloc(ctx->nr_participants, sizeof(unsigned int));
 	ctx->pirs = (GroupElement*) calloc(ctx->nr_participants, sizeof(GroupElement));
-	if(!ctx->r || !ctx->s || !ctx->permutation || !ctx->pirs) {
+	ctx->pirs = (GroupElement*) calloc(ctx->nr_participants, sizeof(GroupElement));
+	if(!ctx->r || !ctx->s || !ctx->permutation || !ctx->pirs || !ctx->messages) {
 		return out_of_memory;
 	}
 	return no_error;
@@ -127,6 +132,11 @@ enum cmix_error initialize_mix_randomness(struct CMixContext* ctx) {
 	return no_error;
 }
 
+enum cmix_error generate_random_message(struct CMixContext* ctx, size_t index) {
+	ctx->messages[index] = ctx->api.get_group_element(true);
+	return no_error;
+}
+
 size_t get_group_element_array_size(struct CMixContext const* ctx) {
 	return ctx->api.get_group_element_array_size();
 }
@@ -200,12 +210,20 @@ enum cmix_error multiply_s(struct CMixContext const* ctx, char* r_out_buffer, ch
 	return no_error;
 }
 
-enum cmix_error key_exchange(struct CMixContext const* ctx, GroupElement* shared_key, char* public_key_buffer, char* exchange_value_buffer, char const* pubkey, char const* value) {
+enum cmix_error key_exchange_init(struct CMixContext const* ctx, char* pubkey_buffer, char* value_buffer, GroupElement* priv_el) {
+	*priv_el = ctx->api.get_group_element(true);
+	GroupElement value = ctx->api.get_key_exchange_value(priv_el);
+	
+	get_public_key(ctx, pubkey_buffer);
+	element_to_buffer(ctx, value_buffer, value);
+	return no_error;
+}
+
+enum cmix_error key_exchange_responder(struct CMixContext const* ctx, GroupElement* shared_key, char* public_key_buffer, char* exchange_value_buffer, char const* pubkey, char const* value) {
 	GroupElement priv_el = ctx->api.get_group_element(true);
 	GroupElement ex_val = ctx->api.get_key_exchange_value(priv_el);
 	
 	size_t el_len = get_group_element_array_size(ctx);
-	
 	*shared_key = ctx->api.derive_shared_key(ctx->keypair, (unsigned char*)pubkey, el_len, (unsigned char*)value, el_len, priv_el, true);
 	
 	element_to_buffer(ctx, public_key_buffer, ctx->keypair.pub);
@@ -217,15 +235,24 @@ enum cmix_error key_exchange(struct CMixContext const* ctx, GroupElement* shared
 	return no_error;
 }
 
-enum cmix_error post_process(struct CMixContext* ctx, char const* r_epirs, char const* m_epirs, size_t index) {
-	GroupElement x = ctx->api.array_to_element(r_epirs, get_group_element_array_size(ctx), true);
+enum cmix_error key_exchange_initiator(struct CMixContext const* ctx, GroupElement* shared_key, char const* pubkey, char const* value, GroupElement priv_el) {
+	size_t el_len = get_group_element_array_size(ctx);
+	*shared_key = ctx->api.derive_shared_key(ctx->keypair, (unsigned char*)pubkey, el_len, (unsigned char*)value, el_len, priv_el, false);
 	
+	return no_error;
+}
+
+enum cmix_error post_process(struct CMixContext* ctx, char* r_out, char* m_out, char const* r_epirs, char const* m_epirs, size_t index) {
+	GroupElement x = ctx->api.array_to_element(r_epirs, get_group_element_array_size(ctx), true);
 	GroupElement D = ctx->api.get_decryption_share(x, ctx->keypair.sec);
+	element_to_buffer(ctx, r_out, D);
 	
 	GroupElement msg = ctx->api.array_to_element(m_epirs, get_group_element_array_size(ctx), true);
 	GroupElement pirs = ctx->api.multiply(D, msg, true);
+	element_to_buffer(ctx, m_out, pirs);
+	
+	ctx->pirs = pirs; // this is not always usable as only the last node will be able to use this effectively, but we store it anyways.
 	
-	ctx->pirs[index] = pirs;
 	ctx->api.free_group_element(x);
 	ctx->api.free_group_element(D);
 	ctx->api.free_group_element(msg);