Guides / CRC32C

CRC32C (Castagnoli)

A Practical 32-bit Checksum for Modern Systems

Important

CRC32C is also non-cryptographic. It improves practical error detection over legacy CRC32 for many workloads, but it is still not suitable for security.

What is CRC32C?

CRC32C is a 32-bit cyclic redundancy check that uses the Castagnoli polynomial (0x82f63b78 in reflected form). It is widely used in distributed storage, filesystems, and network stacks.

Why Castagnoli?

  • Strong error-detection properties for common message sizes
  • Broad adoption in modern infrastructure protocols
  • Fast implementations with CPU acceleration on many platforms

Key Properties

  • Output size: 32 bits (8 hex characters)
  • Default polynomial: 0x82f63b78 (Castagnoli)
  • Custom polynomial: Supported in this app

Use Cases

  • Block-level integrity in storage paths
  • High-throughput pipelines where speed matters
  • Protocol compatibility where CRC32C is required

Try CRC32C

Try CRC32C Calculator

Key Takeaways

  • CRC32C is checksum technology, not cryptographic protection
  • Castagnoli polynomial improves practical error detection behavior
  • Use it where systems explicitly require CRC32C compatibility
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