From aaa225771694c5b63da1500536064c30bd877a28 Mon Sep 17 00:00:00 2001
From: Conor Patrick <conorpp@vt.edu>
Date: Sat, 26 May 2018 11:36:55 -0400
Subject: [PATCH] start aes_gcm

---
 Makefile         | 13 +++++++++++--
 crypto.h         | 10 +++++++---
 crypto/aes_gcm.c | 47 +++++++++++++++++++++++++++++++++++++++++++++++
 main.c           |  3 ++-
 4 files changed, 67 insertions(+), 6 deletions(-)
 create mode 100644 crypto/aes_gcm.c

diff --git a/Makefile b/Makefile
index 4a92632..9c77936 100644
--- a/Makefile
+++ b/Makefile
@@ -13,15 +13,24 @@ src = $(wildcard *.c) $(wildcard crypto/*.c) crypto/tiny-AES-c/aes.c
 obj = $(src:.c=.o) uECC.o
 
 LDFLAGS = -Wl,--gc-sections ./tinycbor/lib/libtinycbor.a
-CFLAGS = -O2 -fdata-sections -ffunction-sections -I./tinycbor/src -I./crypto -I./crypto/micro-ecc/ -Icrypto/tiny-AES-c/
+CFLAGS = -O2 -fdata-sections -ffunction-sections -I./tinycbor/src -I./crypto -I./crypto/micro-ecc/ -Icrypto/tiny-AES-c/ -I.
 
 name = main
 
+all: main
+
+test: testgcm
+
 $(name):  $(obj)
 	$(CC) $(LDFLAGS) -o $@ $(obj) $(LDFLAGS)
 
+testgcm: $(obj)
+	$(CC) -c main.c $(CFLAGS) -DTEST -o main.o
+	$(CC) -c crypto/aes_gcm.c $(CFLAGS) -DTEST -o crypto/aes_gcm.o
+	$(CC) $(LDFLAGS) -o $@ $^ $(LDFLAGS)
+
 uECC.o: ./crypto/micro-ecc/uECC.c
 	$(CC) -c -o $@ $^ -O2 -fdata-sections -ffunction-sections -DuECC_PLATFORM=$(platform) -I./crypto/micro-ecc/
 
 clean:
-	rm -f *.o main.exe main
+	rm -f *.o main.exe main crypto/tiny-AES-c/*.o crypto/*.o crypto/micro-ecc/*.o
diff --git a/crypto.h b/crypto.h
index 6ca99e5..ac7bed0 100644
--- a/crypto.h
+++ b/crypto.h
@@ -1,6 +1,7 @@
 #ifndef _CRYPTO_H
 #define _CRYPTO_H
 
+#include <stddef.h>
 
 #define USE_SOFTWARE_IMPLEMENTATION
 
@@ -16,7 +17,7 @@ void crypto_sha256_hmac_final(uint8_t * key, uint32_t klen, uint8_t * hmac);
 void crypto_ecc256_init();
 void crypto_ecc256_derive_public_key(uint8_t * data, int len, uint8_t * x, uint8_t * y);
 
-void crypto_ecc256_load_key(uint8_t * data, int len);
+void crypto_ecc256_load_key(uint8_t * data, int len, uint8_t * data2, int len2);
 void crypto_ecc256_load_attestation_key();
 void crypto_ecc256_sign(uint8_t * data, int len, uint8_t * sig);
 
@@ -26,8 +27,11 @@ void crypto_ecc256_make_key_pair(uint8_t * pubkey, uint8_t * privkey);
 void crypto_ecc256_shared_secret(const uint8_t * pubkey, const uint8_t * privkey, uint8_t * shared_secret);
 
 // Key must be 32 bytes
-void crypto_aes256_init(uint8_t * key);
-void crypto_aes256_reset_iv();
+#define CRYPTO_TRANSPORT_KEY            NULL
+#define CRYPTO_MASTER_KEY               NULL
+
+void crypto_aes256_init(uint8_t * key, uint8_t * nonce);
+void crypto_aes256_reset_iv(uint8_t * nonce);
 
 // buf length must be multiple of 16 bytes
 void crypto_aes256_decrypt(uint8_t * buf, int lenth);
diff --git a/crypto/aes_gcm.c b/crypto/aes_gcm.c
new file mode 100644
index 0000000..74786dc
--- /dev/null
+++ b/crypto/aes_gcm.c
@@ -0,0 +1,47 @@
+#include <stdint.h>
+#include <stdlib.h>
+#include <string.h>
+#include <stdio.h>
+
+#include "aes.h"
+#include "crypto.h"
+#include "util.h"
+
+#define BLOCK_SIZE 16
+
+static struct AES_ctx aes_ctx;
+
+// void AES_CTR_xcrypt_buffer(struct AES_ctx* ctx, uint8_t* buf, uint32_t length);
+
+int8_t crypto_aes256_gcm_encrypt(uint8_t * data, uint32_t length, uint8_t * authtag)
+{
+    memset(authtag, 0, BLOCK_SIZE);
+    AES_CTR_xcrypt_buffer(&aes_ctx, authtag, BLOCK_SIZE);
+
+    return 0;
+}
+
+#ifdef TEST
+
+int main(int argc, char * argv[])
+{
+    uint8_t nonce[16];
+    uint8_t key[32];
+    uint8_t authtag[BLOCK_SIZE];
+
+    uint8_t * authtag1 = "\x53\x0f\x8a\xfb\xc7\x45\x36\xb9\xa9\x63\xb4\xf1\xc4\xcb\x73\x8b";
+
+    memset(nonce,0,16);
+    memset(key,0,16);
+
+    AES_init_ctx_iv(&aes_ctx, key, nonce);
+
+    crypto_aes256_gcm_encrypt(NULL, 0, authtag);
+
+    printf("Auth tag: "); dump_hex(authtag, BLOCK_SIZE);
+
+
+    return 0;
+}
+
+#endif
diff --git a/main.c b/main.c
index c76cf94..d73f835 100644
--- a/main.c
+++ b/main.c
@@ -19,7 +19,7 @@ static void check_ret(CborError ret)
     }
 }
 
-
+#ifndef TEST
 int main(int argc, char * argv[])
 {
     set_logging_mask(
@@ -61,3 +61,4 @@ int main(int argc, char * argv[])
     printf("done\n");
     return 0;
 }
+#endif