AI Character Card Security: What You Need to Know

Character cards are just files. They contain text and images. But they can also contain hidden data, malicious scripts, or information you don't want to share. If you're importing character cards from the internet, you need to understand the security risks.

This isn't about paranoia. It's about being informed. Here's what you need to know about character card security.

The Risks

Character cards are primarily text files wrapped in PNG images. The text contains metadata: descriptions, personality traits, dialogue examples. But that text can also contain:

  • Personal information: Some creators include their real name, email, or social media in the metadata. If you import their card, you're storing that information.
  • Malicious scripts: While rare, it's technically possible to embed malicious code in a character card. Most platforms sanitize this, but not all do.
  • Hidden data: Some cards contain extra metadata that isn't displayed but is stored in the file. This could include tracking information or other hidden content.
  • Encoded payloads: Some malicious cards encode JavaScript or other code in base64 within the metadata. While most platforms decode this, not all do, and some may execute it.

How to Stay Safe

A 2024 cybersecurity study by the Digital Privacy Foundation found that 15% of online file converters collect and store user-uploaded files for at least 24 hours. This data underscores the importance of using browser-based tools that never transmit your files to external servers.

Here are practical steps to protect yourself:

  • Only import from trusted sources: If you don't know the creator, be cautious. Check their reputation in the community.
  • Inspect the metadata: Before importing, open the card in a text editor and look at the raw JSON. Does it contain anything suspicious? Personal information? Hidden data?
  • Use browser-based converters: Our tool runs entirely in your browser. Your card never leaves your device. No server, no cloud, no data collection.
  • Keep your software updated: Make sure your frontend (SillyTavern, KoboldAI, etc.) is up to date. Updates often include security patches.
  • Don't import cards from unknown URLs: If someone sends you a link to a character card, don't just click it. Download it, inspect it, then import it.
  • Use a sandbox environment: If you're unsure about a card, test it in a sandbox or virtual machine before importing it into your main setup.

Why Browser-Based Conversion Matters

When you use a cloud-based converter, your character card is uploaded to their server. They can read it, store it, or share it. Even if they say they don't, you have no way to verify that.

Browser-based conversion is different. The card never leaves your device. The conversion happens in your browser using JavaScript. No server, no cloud, no data collection. This is the only way to ensure true privacy.

That's why we built our tools to run entirely in the browser. We don't collect your data. We don't store your cards. We don't have a server to hack. Your character cards are yours, and they stay yours. This isn't just a marketing claim — you can verify it yourself by opening your browser's developer tools and watching the network tab during a conversion. No requests are made to any server.

Red Flags to Watch For

Here are signs that a character card might be malicious or suspicious:

  • Unusually large file size: If a character card is over 5MB, it might contain hidden data or compression issues.
  • Strange metadata: If the JSON contains fields you don't recognize, inspect them carefully.
  • Links in the description: Some cards contain links to external websites. Be cautious about where these lead.
  • Requests for personal information: If a card asks for your email, name, or other personal data, don't import it.
  • Excessive permissions: If a card requests access to your system or asks you to run scripts, that's a major red flag.
  • Unusual file extensions: If a file claims to be a PNG but has a .js or .exe extension, it's definitely malicious.

Being cautious doesn't mean you need to be paranoid. Just take a few seconds to inspect any card you're about to import. It's the same mindset you'd use when downloading a file from the internet — a little caution goes a long way. And remember, if something feels off, trust your instincts and don't import it.

Coming Soon: CharacterCardGenerator

We're building CharacterCardGenerator.com with security in mind. Every card generated will be clean, properly formatted, and free of hidden data. You'll be able to inspect the metadata before exporting, and all conversions will happen locally in your browser. We are still in development, but if you want early access, sign up for updates. It will be free to start with a credit system for power features.