From a81b99b9b1fbd8eae9f819a2d997a2cef0e2efea Mon Sep 17 00:00:00 2001
From: iceman1001 <iceman@iuse.se>
Date: Tue, 5 Apr 2016 04:49:34 +0200
Subject: [PATCH] ADD: @zhovner 's decryption of trace data to mfkey64

---
 tools/mfkey/example_trace.txt | 63 +++++++++++++++++++++++++++++++++++
 tools/mfkey/mfkey64.c         | 42 +++++++++++++++++++++--
 2 files changed, 103 insertions(+), 2 deletions(-)

diff --git a/tools/mfkey/example_trace.txt b/tools/mfkey/example_trace.txt
index 83dd157c..5a8a521a 100644
--- a/tools/mfkey/example_trace.txt
+++ b/tools/mfkey/example_trace.txt
@@ -23,3 +23,66 @@
 ::        <uid>    <nt>     <nr>     <ar>     <at>
 ./mfkey64 9C599B32 82A4166C A1E458CE 6EEA41E0 5CADF439
 ./mfkey64 52B0F519 5417D1F8 4D545EA7 E15AC8C2 5056e41b
+
+### Communication decryption
+
+
+RDR	26
+TAG	04 00
+RDR	93 20
+TAG	14 57 9f 69 b5
+RDR	93 70 14 57 9f 69 b5 2e 51
+TAG	08 b6 dd
+RDR	60 14 50 2d
+TAG	ce 84 42 61
+RDR	f8 04 9c cb 05 25 c8 4f
+TAG	94 31 cc 40
+RDR	70 93 df 99
+TAG	99 72 42 8c e2 e8 52 3f 45 6b 99 c8 31 e7 69 dc ed 09
+RDR	8c a6 82 7b
+TAG	ab 79 7f d3 69 e8 b9 3a 86 77 6b 40 da e3 ef 68 6e fd
+RDR	c3 c3 81 ba
+TAG	49 e2 c9 de f4 86 8d 17 77 67 0e 58 4c 27 23 02 86 f4
+RDR	fb dc d7 c1
+TAG	4a bd 96 4b 07 d3 56 3a a0 66 ed 0a 2e ac 7f 63 12 bf
+RDR	9f 91 49 ea
+
+
+./mfkey64 14579f69 ce844261 f8049ccb 0525c84f 9431cc40 7093df99 9972428ce2e8523f456b99c831e769dced09 8ca6827b ab797fd369e8b93a86776b40dae3ef686efd c3c381ba 49e2c9def4868d1777670e584c27230286f4 fbdcd7c1 4abd964b07d3563aa066ed0a2eac7f6312bf 9f9149ea
+
+Recovering key for:
+  uid: 14579f69
+   nt: ce844261
+ {nr}: f8049ccb
+ {ar}: 0525c84f
+ {at}: 9431cc40
+{enc0}: 7093df99
+{enc1}: 9972428ce2e8523f456b99c831e769dced09
+{enc2}: 8ca6827b
+{enc3}: ab797fd369e8b93a86776b40dae3ef686efd
+{enc4}: c3c381ba
+{enc5}: 49e2c9def4868d1777670e584c27230286f4
+{enc6}: fbdcd7c1
+{enc7}: 4abd964b07d3563aa066ed0a2eac7f6312bf
+{enc8}: 9f9149ea
+
+LFSR succesors of the tag challenge:
+  nt': 76d4468d
+ nt'': d5f3c476
+
+Keystream used to generate {ar} and {at}:
+  ks2: 73f18ec2
+  ks3: 41c20836
+
+Decrypted communication:
+{dec0}: 3014a7fe
+{dec1}: c26935cfdb95c4b4a27a84b8217ae9e48217
+{dec2}: 30152eef
+{dec3}: 493167c536c30f8e220b09675687067d4b31
+{dec4}: 3016b5dd
+{dec5}: 493167c536c30f8e220b09675687067d4b31
+{dec6}: 30173ccc
+{dec7}: 0000000000007e178869000000000000c4f2
+{dec8}: 61148834
+
+Found Key: [091e639cb715]
\ No newline at end of file
diff --git a/tools/mfkey/mfkey64.c b/tools/mfkey/mfkey64.c
index 8bb59ecc..b09eeaeb 100755
--- a/tools/mfkey/mfkey64.c
+++ b/tools/mfkey/mfkey64.c
@@ -22,23 +22,42 @@ int main (int argc, char *argv[]) {
 	printf("Recover key from only one complete authentication!\n\n");
 
 	if (argc < 6) {
-		printf(" syntax: %s <uid> <nt> <nr> <ar> <at>\n\n",argv[0]);
+		printf(" syntax: %s <uid> <nt> <{nr}> <{ar}> <{at}> [enc...]\n\n", argv[0]);
 		return 1;
 	}
 
+	int encc = argc - 6;
+	int enclen[encc];
+	uint8_t enc[encc][120]; 
+
 	sscanf(argv[1],"%x",&uid);
 	sscanf(argv[2],"%x",&nt);
 	sscanf(argv[3],"%x",&nr_enc);
 	sscanf(argv[4],"%x",&ar_enc);
 	sscanf(argv[5],"%x",&at_enc);
-
+	for (int i = 0; i < encc; i++) {
+		enclen[i] = strlen(argv[i + 6]) / 2;
+		for (int i2 = 0; i2 < enclen[i]; i2++) {
+			sscanf(argv[i+6] + i2*2,"%2x", (uint8_t*)&enc[i][i2]);
+		}
+	}
+	
 	printf("Recovering key for:\n");
+
 	printf("  uid: %08x\n",uid);
 	printf("   nt: %08x\n",nt);
 	printf(" {nr}: %08x\n",nr_enc);
 	printf(" {ar}: %08x\n",ar_enc);
 	printf(" {at}: %08x\n",at_enc);
 
+	for (int i = 0; i < encc; i++) {
+		printf("{enc%d}: ", i);
+		for (int i2 = 0; i2 < enclen[i]; i2++) {
+			printf("%02x", enc[i][i2]);
+		}
+		printf("\n");
+	}
+
 	// Generate lfsr succesors of the tag challenge
 	printf("\nLFSR succesors of the tag challenge:\n");
 	printf("  nt': %08x\n",prng_successor(nt, 64));
@@ -54,6 +73,25 @@ int main (int argc, char *argv[]) {
 	printf("  ks3: %08x\n",ks3);
 
 	revstate = lfsr_recovery64(ks2, ks3);
+
+	// Decrypting communication using keystream if presented
+	if (argc > 6 ) {
+		printf("\nDecrypted communication:\n");
+		uint8_t ks4; 
+		int rollb = 0;
+		for (int i = 0; i < encc; i++) {
+			printf("{dec%d}: ", i);
+			for (int i2 = 0; i2 < enclen[i]; i2++) {  
+				ks4 = crypto1_byte(revstate, 0, 0);
+				printf("%02x", ks4 ^ enc[i][i2]);
+				rollb += 1;
+			}
+			printf("\n");
+		}
+		for (int i = 0; i < rollb; i++)
+			lfsr_rollback_byte(revstate, 0, 0);
+	}
+  
 	lfsr_rollback_word(revstate, 0, 0);
 	lfsr_rollback_word(revstate, 0, 0);
 	lfsr_rollback_word(revstate, nr_enc, 1);
-- 
2.39.2