# Checksum

Source URL: https://help.blockstream.com/education/glossary/checksum
Updated: 2026-05-26T17:23:11.000Z
Letter: C

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A checksum is a simple way of detecting errors or mistakes in data.

When it comes to Bitcoin, checksums are calculated using a 32-bit portion of a [SHA256](https://help.blockstream.com/education/glossary/sha-256) hash (the last four bytes) and are used to detect incorrect addresses, helping to prevent transactions from going wrong due to simple typos. A checksum only uses 32 bits because it is more than enough to uniquely identify a Bitcoin address or transaction while still ensuring network efficiency.

Checksumming is the process of computing and confirming checksums quickly to validate data without requiring extensive processing or third-party involvement.

Navigation: Blockstream Help Center > Education > Glossary > Checksum

## Related Terms in This Letter
- [Cold Storage](https://help.blockstream.com/education/glossary/cold-storage-security)
- [Confidential Transactions (CT)](https://help.blockstream.com/education/glossary/confidential-transactions)
- [Core Lightning (CLN)](https://help.blockstream.com/education/glossary/core-lightning)
- [Checksum](https://help.blockstream.com/education/glossary/checksum) (current)