# What is the security PIN and why do I need it?

**Category**: Cloud Sync & Sharing  
**Language**: EN  
**Source**: [JustSplitBill Help](https://www.justsplitbill.com/help.html)

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The **4-digit PIN** protects your cloud data from unauthorized changes. Anyone can *view* a session by loading its code, but only someone who knows the PIN can **update** or **delete** it. This prevents other people from accidentally overwriting your group's data.