From cfbd0db491f012ff945ab629442610eb19c20c58 Mon Sep 17 00:00:00 2001
From: Matthias Ringwald <matthias@ringwald.ch>
Date: Sat, 7 Dec 2019 22:34:33 +0100
Subject: [PATCH] btstack_crypto: use rijndael aes128 if ENABLE_SOFTWARE_AES128
 [a2472]

---
 src/btstack_crypto.c | 39 +++++++++++++++++++++++++++++++++------
 src/btstack_crypto.h | 11 +++++++++++
 2 files changed, 44 insertions(+), 6 deletions(-)

diff --git a/src/btstack_crypto.c b/src/btstack_crypto.c
index df2cbe40f..ab09c12a4 100644
--- a/src/btstack_crypto.c
+++ b/src/btstack_crypto.c
@@ -46,6 +46,30 @@
 #include "btstack_util.h"
 #include "hci.h"
 
+//
+// AES128 Configuration
+//
+
+// By default, AES128 is computed by Bluetooth Controller using HCI Command/Event asynchronously
+// as fallback/alternative, a software implementation can be used
+// configure ECC implementations
+#if defined(HAVE_AES128) && defined(ENABLE_SOFTWARE_AES128)
+#error "If you have custom AES128 implementation (HAVE_AES128), please disable software AES128 (ENABLE_SOFTWARE_AES128) in bstack_config.h"
+#endif
+
+#ifdef ENABLE_SOFTWARE_AES128
+#define HAVE_AES128
+#include "rijndael.h"
+#endif
+
+#ifdef HAVE_AES128
+#define USE_BTSTACK_AES128
+#endif
+
+//
+// ECC Configuration
+// 
+
 // backwards-compatitility ENABLE_MICRO_ECC_FOR_LE_SECURE_CONNECTIONS -> ENABLE_MICRO_ECC_P256
 #if defined(ENABLE_MICRO_ECC_FOR_LE_SECURE_CONNECTIONS) && !defined(ENABLE_MICRO_ECC_P256)
 #define ENABLE_MICRO_ECC_P256
@@ -78,12 +102,6 @@
 #define ENABLE_ECC_P256
 #endif
 
-// Software AES128
-#ifdef HAVE_AES128
-#define USE_BTSTACK_AES128
-void btstack_aes128_calc(const uint8_t * key, const uint8_t * plaintext, uint8_t * result);
-#endif
-
 // degbugging
 // #define DEBUG_CCM
 
@@ -146,6 +164,15 @@ static mbedtls_ecp_group   mbedtls_ec_group;
 
 #endif /* ENABLE_ECC_P256 */
 
+#ifdef ENABLE_SOFTWARE_AES128
+// AES128 using public domain rijndael implementation
+void btstack_aes128_calc(const uint8_t * key, const uint8_t * plaintext, uint8_t * ciphertext){
+    uint32_t rk[RKLENGTH(KEYBITS)];
+    int nrounds = rijndaelSetupEncrypt(rk, &key[0], KEYBITS);
+    rijndaelEncrypt(rk, nrounds, plaintext, ciphertext);
+}
+#endif
+
 static void btstack_crypto_done(btstack_crypto_t * btstack_crypto){
     btstack_linked_list_pop(&btstack_crypto_operations);
     (*btstack_crypto->context_callback.callback)(btstack_crypto->context_callback.context);
diff --git a/src/btstack_crypto.h b/src/btstack_crypto.h
index 6d32bc142..78fb4bc06 100644
--- a/src/btstack_crypto.h
+++ b/src/btstack_crypto.h
@@ -270,6 +270,17 @@ void btstack_crypto_ccm_encrypt_block(btstack_crypto_ccm_t * request, uint16_t l
  */
 void btstack_crypto_ccm_decrypt_block(btstack_crypto_ccm_t * request, uint16_t len, const uint8_t * ciphertext, uint8_t * plaintext, void (* callback)(void * arg), void * callback_arg);
 
+#ifdef HAVE_AES128
+/** 
+ * Encrypt plaintext using AES128
+ * @note Prototype for custom AES128 implementation
+ * @param key (16 bytes)
+ * @param plaintext (16 bytes)
+ * @param ciphertext (16 bytes)
+ */
+void btstack_aes128_calc(const uint8_t * key, const uint8_t * plaintext, uint8_t * ciphertext);
+#endif
+
 // PTS testing only - not possible when using Buetooth Controller for ECC operations
 void btstack_crypto_ecc_p256_set_key(const uint8_t * public_key, const uint8_t * private_key);