From 87c05faffd9255f056255ee43ff0da8d461dcb4f Mon Sep 17 00:00:00 2001
From: merlokk <807634+merlokk@users.noreply.github.com>
Date: Fri, 20 Aug 2021 23:02:52 +0300
Subject: [PATCH] add link

---
 client/src/cmdhfmfdes.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/client/src/cmdhfmfdes.c b/client/src/cmdhfmfdes.c
index 40ee8f032..1b5d003ae 100644
--- a/client/src/cmdhfmfdes.c
+++ b/client/src/cmdhfmfdes.c
@@ -4629,6 +4629,8 @@ static int DesfileReadFileAndPrint(DesfireContext *dctx, uint8_t fnum, int filet
                     transactionCounter = cnt;
                     PrintAndLogEx(SUCCESS, "Transaction counter: %d (0x%08x)", cnt, cnt);
                 } else {
+                    // For composing TMC the two subparts are concatenated as follows: actTMC || sesTMC. Both subparts are represented LSB first.
+                    // MF2DLHX0.pdf, 10.3.2.1 Transaction MAC Counter, page 41
                     uint32_t actTMC = MemLeToUint2byte(&resp[0]);
                     uint32_t sessTMC = MemLeToUint2byte(&resp[2]);
                     transactionCounter = actTMC;