From 1a5bbf0ee895bbd66fb3ce66be44b1074bb20324 Mon Sep 17 00:00:00 2001
From: Tad <tad@spotco.us>
Date: Wed, 28 Feb 2018 08:21:28 -0500
Subject: [PATCH] Build time variable for AES-256 encryption

Change-Id: I25eba5939c965323e4ffa6d95c6736b671c51e09
---
 Android.mk  | 4 ++++
 cryptfs.cpp | 9 ++++++++-
 2 files changed, 12 insertions(+), 1 deletion(-)

diff --git a/Android.mk b/Android.mk
index 14bf99a..0e9f3e1 100644
--- a/Android.mk
+++ b/Android.mk
@@ -115,6 +115,10 @@ ifeq ($(TARGET_HW_DISK_ENCRYPTION),true)
   vold_cflags += -DCONFIG_HW_DISK_ENCRYPTION
 endif
 
+ifeq ($(TARGET_WANTS_STRONG_ENCRYPTION),true)
+LOCAL_CFLAGS += -DCONFIG_STRONG_ENCRYPTION
+endif
+
 ifneq ($(TARGET_EXFAT_DRIVER),)
   vold_cflags += -DCONFIG_EXFAT_DRIVER=\"$(TARGET_EXFAT_DRIVER)\"
   mini_src_files += fs/Exfat.cpp
diff --git a/cryptfs.cpp b/cryptfs.cpp
index f01929a..7fb3ffa 100644
--- a/cryptfs.cpp
+++ b/cryptfs.cpp
@@ -75,9 +75,17 @@ extern "C" {
 
 #define DM_CRYPT_BUF_SIZE 4096
 
+#ifdef CONFIG_STRONG_ENCRYPTION
+#define HASH_COUNT 6000
+#define KEY_LEN_BYTES 32
+#define IV_LEN_BYTES 32
+#define RSA_KEY_SIZE 4096
+#else
 #define HASH_COUNT 2000
 #define KEY_LEN_BYTES 16
 #define IV_LEN_BYTES 16
+#define RSA_KEY_SIZE 2048
+#endif
 
 #define KEY_IN_FOOTER  "footer"
 
@@ -93,7 +101,6 @@ extern "C" {
 
 #define TABLE_LOAD_RETRIES 10
 
-#define RSA_KEY_SIZE 2048
 #define RSA_KEY_SIZE_BYTES (RSA_KEY_SIZE / 8)
 #define RSA_EXPONENT 0x10001
 #define KEYMASTER_CRYPTFS_RATE_LIMIT 1  // Maximum one try per second
-- 
2.16.2