I’ll share some redistribution prevention strategies for digital contents that I’ve been thinking about.

Prerequisites

Want to prevent redistribution of digital content sold on an EC site after purchase.

The digital content file types I’m considering are:

• PDF files .pdf
• Image files .jpg .png .gif etc.
• Compressed files .zip

Redistribution Prevention Plans for Each Digital Content Type

PDF Files

One redistribution prevention strategy for PDF files is to insert the purchaser’s email address as a watermark on each page.

Image Files

For image file redistribution prevention, you could embed the purchaser’s name or email address in the Exif data. While this doesn’t prevent redistribution, it can serve as a clue to identify who redistributed the content.

Exchangeable image file format (Exif) - Wikipedia

It seems there have been redistribution prevention efforts since the flip phone era.

再配布不可識別子の入れ方 | WEB制作の覚書

ZIP Files

For redistribution prevention with password-protected ZIP files, you could set a unique password for each purchaser.

Aside) Utilizing Blockchain Technology

It appears various companies are working on using blockchain technology to record ownership of digital content.

• ブロックチェーンは著作権やライセンス分野でも使えるのか？ | TechCrunch Japan
• 『進撃の巨人』アートワークの"デジタル所有権"を販売──ブロックチェーンで売買履歴を記録 | CoinDesk Japan | コインデスク・ジャパン
• 音楽、動画、ゲーム…エイベックスがブロックチェーンでコンテンツに証明書──1、2年で開発へ | CoinDesk Japan | コインデスク・ジャパン

That’s all from the Gemba.