add optional assymetric payload encryption

This patch uses the NaCL library to en-/decrypt and authenticate the
payload suitable private and public keys are found. It
- adds crypto.h, containing all crypto logic (including the detection
  if the packet is to be en-/decrypted)
- adds nacl dependency to Makefile (including a switch between
  internal and external nacl)

It also
- changes Makefile to build with -Werror -Wextra
- builds warning-free

1 files changed, 12 insertions, 0 deletions

diff --git a/Makefile b/Makefile
index 1509435..87a65e8 100644
--- a/Makefile
+++ b/Makefile
@@ -1,4 +1,13 @@
 BIN=hbbpd hbbpc
+ 
+ifndef EXTERNAL_NACL
+CFLAGS  += -Inacl/include/
+LDFLAGS += -Lnacl/lib/
+NACL_DEP = nacl/include
+endif
+
+CFLAGS +=-std=c99 -Wall -Wextra -fwhole-program -Os
+LDFLAGS +=-lnacl nacl/lib/randombytes.o
 
 all: $(BIN)
 
@@ -6,6 +15,9 @@ all: $(BIN)
 clean:
 	rm -f $(BIN) *~
 
+%: %.c common.h crypto.h $(NACL_DEP)
+	$(CC) -o $@ $< $(LDFLAGS) $(CFLAGS)
+
 nacl/include:
 	mkdir nacl
 	wget http://hyperelliptic.org/nacl/nacl-20110221.tar.bz2 -O - | tar jxf - -C nacl