toolsTLVs EMV TLV parsing guide

Introduce the parsing of TLV data using on-site tools.

TLV is the common abbreviation of Tag + Length + Value data encoding.

Originally TLV encoding described in Abstract Syntax Notation (ASN.1) Basic Encoding Rules (BER) or ISO 8825-1.
This specification and TLV encoding used as the core for range of other data packing standards.
Like EMV, and all derived from EMV card brands specifications, NFC tags, in different communication protocols.

On site you may use different parsing tools where specific Tags and tag Values content might be dissected.

To get access to parsing tools required login to site.

Then in the tools list we can filter by required labels.
You may parse Tag + Length + Value series "TLVs", Tag + Length series "TLs" or Tag + Value data.
In case filter with general "TLVs" tool you may see different Card brand specifications, Generic ISO 7816, EMV or ASN.1 BER
and few different tools which use same encoding rules.

Let's take a look to the EMV tags data parsing tool.

The EMV TLV data is binary. Only Hexadecimal characters allowed to use. It is noticid in the entry field.

TV tool is only detect Tag and Value.
Tag can be one or several bytes. Value is variable depending of specification.

For example:
1) EMV Tag 0x95 - Terminal Verification Results (TVR) with 5 bytes of value.
"95 0080048000"

2) EMV Tag 0x9F33 - Terminal Capabilities with 3 bytes of value.
"9F33 60D0C8"

Here Length of value not used. All bytes after Tag recognized as Value.

TLVs tool detects Tag + Length + Value data or sequence of TLV blocks.
Here Length byte presented and used by parser. If used Length is wrong the Value might be incorrectly extracted.

The same examples as before but now with Length bytes in the middle.
1) TVR: "95 05 0080048000".
2) Terminal Capability: "9F33 03 60D0C8".
3) Or both. Two blocks of TLV: "95 05 0080048000 9F33 03 60D0C8".

Some complex examples:
4) From financial message request EMV data. Sequesnce of TLV blocks sent online for ARQC cryptogram validation and ARPC cryptogram calculation:

5) From Card-Terminal traces APDU reply data for Read command. EMV template Tag 0x70 with sub-Tags:

All TLVs tools on site are similar but used different list of Tags and their meanings.
For example Visa Contactless Payment Specification "VCPS" used list of Tags from Chip card specification ISO 7816, EMV and few VCPS related tags.

That's all for on-site TLV parsing tools. Register to use these tools.

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