How to Decode TLV Quickly

In TLV, the format is Tag, Length, and Value. The TLV protocol needs this type of data. Here you will know how to decode TLV data. According to IBM, TLV data is three parts. The tag tells what type of data it is. The length field denotes the length of the value. The Value-field denotes the actual value.


Structure of TLV.


TLV comprises three field values. 

  1. Tag
  2. Length
  3. Value


EMV formulated different tags. They have their meanings. Usually, the Tag and Length together takes 1 to 4 bytes.


TLV Value Decoding Method

The Best example for TLV.


In the below example, you can find the sample TAG, LENGTH, and VALUE fields.


[Tag][Value Length][Value] (ex. "9F4005F000F0A001")

where

Tag Name = 9F40

Value Length (in bytes) = 05 

Value (Hex representation of bytes. Example, "F0" – 1-byte) = F000F0A001


In the above message, tag 9F40 has some meaning designed by EMV company. Here you can find a list of EMV Tags.


How to read the TLV


Tag: 1 or 2 bytes

Length: Length of the Value.

F0-00-F0-A0-01 ==> 5 Bytes


The 'F0', for example, is the HEX value of length '1' byte. So the total length of the value '5' bytes.


Keep Reading


  1. Tag Length Value Tutorial

Comments

Popular posts from this blog

How to Fix Python Syntax Errors Quickly

Python Ideas to Remove HTML tags

Hyperledger Fabric: 20 Real Interview Questions

Python: Swap Two Strings no need to Define Third Variable

Calculate Circle Area the Logic You Need to write in Python