2 files changed, 26 insertions, 12 deletions

diff --git a/libcmix/cmix.c b/libcmix/cmix.c
index d21dab5..c60f441 100644
--- a/libcmix/cmix.c
+++ b/libcmix/cmix.c
@@ -24,6 +24,17 @@ struct CMixContext initialize_cmix_context(struct Api api) {
 	};
 }
 
+enum cmix_error alloc_mix(struct CMixContext* ctx) {
+	ctx->r = (GroupElement*) calloc(ctx->nr_participants, sizeof(GroupElement));
+	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) {
+		return out_of_memory;
+	}
+	return no_error;
+}
+
 void release_mix(struct CMixContext* ctx) {
 	for(size_t i = 0; i < ctx->nr_participants; ++i) {
 		ctx->api.free_group_element(ctx->r[i]);
@@ -31,9 +42,18 @@ void release_mix(struct CMixContext* ctx) {
 		ctx->api.free_group_element(ctx->pirs[i]);
 	}
 	free(ctx->r);
+	ctx->r = NULL;
+	
 	free(ctx->s);
+	ctx->s = NULL;
+	
 	free(ctx->permutation);
+	ctx->permutation = NULL;
+	
 	free(ctx->pirs);
+	ctx->pirs = NULL;
+	
+	ctx->nr_participants = 0;
 }
 
 void deinitialize(struct CMixContext* ctx)
@@ -77,17 +97,6 @@ enum cmix_error add_public_share(struct CMixContext const* ctx, char* buffer, ch
 	ctx->api.free_group_element(el);
 }
 
-enum cmix_error alloc_mix(struct CMixContext* ctx) {
-	ctx->r = (GroupElement*) calloc(ctx->nr_participants, sizeof(GroupElement));
-	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) {
-		return out_of_memory;
-	}
-	return no_error;
-}
-
 enum cmix_error start_mix(struct CMixContext* ctx, size_t nr_participants) {
 	release_mix(ctx);
 	ctx->nr_participants = nr_participants;
@@ -95,7 +104,10 @@ enum cmix_error start_mix(struct CMixContext* ctx, size_t nr_participants) {
 }
 
 enum cmix_error generate_permutation(struct CMixContext* ctx) {
-	ctx->permutation = (unsigned int*) calloc(ctx->nr_participants, sizeof(unsigned int));
+	if (ctx->nr_participants == 0) {
+		return no_error;
+	}
+	
 	for(unsigned int i = 0; i < ctx->nr_participants; ++i) {
 		ctx->permutation[i] = i;
 	}
diff --git a/libcmix/cmix.h b/libcmix/cmix.h
index 057fd60..8e6f598 100644
--- a/libcmix/cmix.h
+++ b/libcmix/cmix.h
@@ -73,6 +73,8 @@ enum cmix_error get_pub_key_hash(struct CMixContext const* ctx, char** buffer);
 
 enum cmix_error start_mix(struct CMixContext* ctx, size_t nr_participants);
 
+void release_mix(struct CMixContext* ctx);
+
 enum cmix_error initialize_mix_randomness(struct CMixContext* ctx);
 
 enum cmix_error generate_random_message(struct CMixContext* ctx, char* buffer);