envyniv / denpa-qr-inv

investigation into the innards of DPM QR Codes

The Great Denpa Men QR Investigation

Reading

DPM1

• Will only read v6 lM

DPM2-3

• The games pulls garbage data when a field is missing or invalid
• They do not care what format the QR is in as long as the data is valid.
• Despite the QRs having different headers by region, they can be cross-read. If a denpa exists in your house, and you scan a QR from a different region but with same parameters, the game will acknowledge that. If that is not the case, it will just error for incompatibility.

Writing

[#C] DPM1

• Some sort of time-based encryption is applied to the QR.

Reference The Previous QR Editor

[#A] DPM2

• Encoding is much more linear and deterministic.
• QRs are formatted almost readably

WEST

DPM2 EU and NA qrs have the same header but different offsets the first eight bytes are 8C78 C533 CB2C 8DE6 bytes 10 to 2f have the same values in all regions: 302A 039B C089 3DC6 302A 039B C089 3DC6 302A 039B C089 3DC6 302A 039B C089 3DC6 same goes for 70-77 40-6f are some data

US

39-3f have a value of 0b5c 5565 5a58 43af

JAPAN

japanese DPM2 qrs start with 952d 41c1 a1dd 7f2c

[#B] DPM3