From 86d597a510e20fbb354e588343074366a6abede1 Mon Sep 17 00:00:00 2001
From: iceman1001 <iceman@iuse.se>
Date: Mon, 11 Apr 2016 15:25:00 +0200
Subject: [PATCH] ADD:  added @pivi 's faster authentication method from
 'hardnested'  into "hf mf chk" (check keys)  and removed the "halt" command.
 the speedup is great. Together with the previous speedups from making changes
 how the client sends the keys to the device,  make it lightning fast. It
 would be fun to see how much fast it is now.

---
 armsrc/mifarecmd.c | 53 ++++++++++++++++++++++++++++++++++------------
 1 file changed, 40 insertions(+), 13 deletions(-)

diff --git a/armsrc/mifarecmd.c b/armsrc/mifarecmd.c
index 423b6e95..c18aba08 100644
--- a/armsrc/mifarecmd.c
+++ b/armsrc/mifarecmd.c
@@ -613,6 +613,9 @@ int valid_nonce(uint32_t Nt, uint32_t NtEnc, uint32_t Ks1, uint8_t *parity) {
 // Mifare Classic Cards" in Proceedings of the 22nd ACM SIGSAC Conference on 
 // Computer and Communications Security, 2015
 //-----------------------------------------------------------------------------
+#define AUTHENTICATION_TIMEOUT 848			// card times out 1ms after wrong authentication (according to NXP documentation)
+#define PRE_AUTHENTICATION_LEADTIME 400		// some (non standard) cards need a pause after select before they are ready for first authentication 
+
 void MifareAcquireEncryptedNonces(uint32_t arg0, uint32_t arg1, uint32_t flags, uint8_t *datain)
 {
 	uint64_t ui64Key = 0;
@@ -638,9 +641,6 @@ void MifareAcquireEncryptedNonces(uint32_t arg0, uint32_t arg1, uint32_t flags,
 	bool slow = flags & 0x0002;
 	bool field_off = flags & 0x0004;
 	
-	#define AUTHENTICATION_TIMEOUT 848			// card times out 1ms after wrong authentication (according to NXP documentation)
-	#define PRE_AUTHENTICATION_LEADTIME 400		// some (non standard) cards need a pause after select before they are ready for first authentication 
-	
 	LED_A_ON();
 	LED_C_OFF();
 
@@ -965,16 +965,17 @@ void MifareNested(uint32_t arg0, uint32_t arg1, uint32_t calibrate, uint8_t *dat
 // MIFARE check keys. key count up to 85. 
 // 
 //-----------------------------------------------------------------------------
-void MifareChkKeys(uint16_t arg0, uint8_t arg1, uint8_t arg2, uint8_t *datain)
-{
-  // params
+void MifareChkKeys(uint16_t arg0, uint8_t arg1, uint8_t arg2, uint8_t *datain) {
 	uint8_t blockNo = arg0 & 0xff;
 	uint8_t keyType = (arg0 >> 8) & 0xff;
 	bool clearTrace = arg1;
 	uint8_t keyCount = arg2;
 	uint64_t ui64Key = 0;
 	
-	// variables
+	bool have_uid = FALSE;
+	uint8_t cascade_levels = 0;
+	uint32_t timeout = 0;
+	
 	int i;
 	byte_t isOK = 0;
 	uint8_t uid[10] = {0x00};
@@ -999,16 +1000,42 @@ void MifareChkKeys(uint16_t arg0, uint8_t arg1, uint8_t arg2, uint8_t *datain)
 	
 	for (i = 0; i < keyCount; ++i) {
 
-		mifare_classic_halt(pcs, cuid);
-	
-		if (!iso14443a_select_card(uid, NULL, &cuid, true, 0))
-			break;
+		//mifare_classic_halt(pcs, cuid);
 
+		// this part is from Piwi's faster nonce collecting part in Hardnested.
+		if (!have_uid) { // need a full select cycle to get the uid first
+			iso14a_card_select_t card_info;		
+			if(!iso14443a_select_card(uid, &card_info, &cuid, true, 0)) {
+				if (MF_DBGLEVEL >= 1)	Dbprintf("ChkKeys: Can't select card (ALL)");
+				break;
+			}
+			switch (card_info.uidlen) {
+				case 4 : cascade_levels = 1; break;
+				case 7 : cascade_levels = 2; break;
+				case 10: cascade_levels = 3; break;
+				default: break;
+			}
+			have_uid = TRUE;	
+		} else { // no need for anticollision. We can directly select the card
+			if(!iso14443a_select_card(uid, NULL, NULL, false, cascade_levels)) {
+				if (MF_DBGLEVEL >= 1)	Dbprintf("ChkKeys: Can't select card (UID)");
+				continue;
+			}
+		}
+	
 		ui64Key = bytes_to_num(datain + i * 6, 6);
 		
-		if (mifare_classic_auth(pcs, cuid, blockNo, keyType, ui64Key, AUTH_FIRST))
+		if (mifare_classic_auth(pcs, cuid, blockNo, keyType, ui64Key, AUTH_FIRST)) {
+
+			uint8_t dummy_answer = 0;
+			ReaderTransmit(&dummy_answer, 1, NULL);
+			timeout = GetCountSspClk() + AUTHENTICATION_TIMEOUT;
+			
+			// wait for the card to become ready again
+			while(GetCountSspClk() < timeout);
+			
 			continue;
-		
+		}
 		isOK = 1;
 		break;
 	}
-- 
2.39.2