From 37daaa2120960f70d58f670b0e3246a5754d6f21 Mon Sep 17 00:00:00 2001
From: merlokk <807634+merlokk@users.noreply.github.com>
Date: Sat, 29 May 2021 16:20:48 +0300
Subject: [PATCH] GenerateK0AndCp sketch

---
 client/src/cipurse/cipursecrypto.c | 48 ++++++++++++++++++++++++++----
 client/src/cipurse/cipursecrypto.h |  2 +-
 2 files changed, 44 insertions(+), 6 deletions(-)

diff --git a/client/src/cipurse/cipursecrypto.c b/client/src/cipurse/cipursecrypto.c
index 90d6f1722..996d43b1e 100644
--- a/client/src/cipurse/cipursecrypto.c
+++ b/client/src/cipurse/cipursecrypto.c
@@ -23,12 +23,50 @@
 
 uint8_t AESData0[CIPURSE_AES_KEY_LENGTH] = {0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00};
 
-static void CipurseCGenerateK0AndGetCp(CipurseContext *ctx) {
+static void CipurseCGenerateK0AndCp(CipurseContext *ctx) {
+    /*        // session key derivation function
+        // kP := NLM(EXT(kID), rP)
+        // k0 := AES(key=PAD2(kP) XOR PAD(rT),kID) XOR kID
+        var temp1 = CryptoUtils.extFunction(kid, CIPURSE_SECURITY_PARAM_N) ?: return null
+        val kp = CryptoUtils.computeNLM(rP, temp1) ?: return null
+        temp1 = CryptoUtils.pad2(kp) ?: return null
+        val temp2 = CryptoUtils.pad(rT) ?: return null
+        temp1 = temp1 xor temp2
 
+        // session key K0
+        k0 = AesECB.aesEncrypt(temp1, kid) ?: return null
+        k0 = k0 xor kid
+
+        // first frame key k1, function to calculate k1,
+        // k1 := AES(key = RP; k0 XOR RT) XOR (k0 XOR RT)
+        temp1 = k0 xor RT
+        val temp3: ByteArray = AesECB.aesEncrypt(RP, temp1) ?: return null
+        frameKeyi = temp3 xor temp1
+        Log.d(TAG, "frame key=${Utils.toHex(frameKeyi)}")
+
+        // function to caluclate cP := AES(key=k0, RP).
+        // terminal response
+        return AesECB.aesEncrypt(k0, RP)*/
+        
+    uint8_t temp1[CIPURSE_AES_KEY_LENGTH] = {0};
+    uint8_t temp2[CIPURSE_AES_KEY_LENGTH] = {0};
+        
+    // session key derivation function
+    // kP := NLM(EXT(kID), rP)
+    // k0 := AES(key=PAD2(kP) XOR PAD(rT),kID) XOR kID  
+        
+    // session key K0    
+        
+    // first frame key k1, function to calculate k1,
+    // k1 := AES(key = RP; k0 XOR RT) XOR (k0 XOR RT)
+        
+    // function to caluclate cP := AES(key=k0, RP).
+    // terminal response
+    aes_encode(NULL, ctx->k0, ctx->RP, ctx->Cp, CIPURSE_AES_KEY_LENGTH);
 }
 
-static void CipurseCGenerateCT(uint8_t *RT, uint8_t *CT) {
-    
+static void CipurseCGenerateCT(uint8_t *k0, uint8_t *RT, uint8_t *CT) {
+    aes_encode(NULL, k0, RT, CT, CIPURSE_AES_KEY_LENGTH);
 }
 
 void CipurseCGetKVV(uint8_t *key, uint8_t *kvv) {
@@ -78,8 +116,8 @@ void CipurseCAuthenticateHost(CipurseContext *ctx, uint8_t *authdata) {
         return;
     
     CipurseCSetRandomHost(ctx);
-    CipurseCGenerateK0AndGetCp(ctx);
-    CipurseCGenerateCT(ctx->RT, ctx->CT);
+    CipurseCGenerateK0AndCp(ctx);
+    CipurseCGenerateCT(ctx->k0, ctx->RT, ctx->CT);
 
     if (authdata != NULL)
         CipurseCFillAuthData(ctx, authdata);
diff --git a/client/src/cipurse/cipursecrypto.h b/client/src/cipurse/cipursecrypto.h
index f7b330280..c2f8c2de4 100644
--- a/client/src/cipurse/cipursecrypto.h
+++ b/client/src/cipurse/cipursecrypto.h
@@ -36,7 +36,7 @@ typedef struct CipurseContextS {
     uint8_t RT[16];
     uint8_t rT[6];
     
-    uint8_t frameKey0[16];
+    uint8_t k0[16];
     uint8_t cP[16];
     uint8_t CT[16];