Hashing & Checksums
TCP/IP Checksum Digest Calculator
Calculate or verify a digest with TCP/IP Checksum. Enter the data, choose the digest options, then copy the calculated value.
This tool runs open-source code from CyberChef by GCHQ (Apache License 2.0). See open-source credits.
TCP/IP Checksum Digest Calculator uses checksum for the supplied input. It sums big-endian 16-bit words, folds the carry, and returns the complement in hexadecimal.
It sums big-endian 16-bit words, folds the carry, and returns the complement in hexadecimal. This result runs in the browser for this catalog category. Processing runs in the browser.
Checksums detect selected transmission or entry errors; they do not provide confidentiality or adversarial integrity.
Instructions
- Provide text or data for this tool.
- Clear an existing checksum field before calculating its replacement. This applies to TCP/IP Checksum Digest Calculator.
- Prepare the protocol-required header and data bytes before running the operation. This applies to TCP/IP Checksum Digest Calculator.
Example
Input: Supply bytes 00 01 f2 03; the returned value is dfb.
Settings: TCP/IP Checksum Digest Calculator: Enter the complete byte sequence that needs summation. No packet parser or pseudo-header builder runs in this operation.
Result: It sums big-endian 16-bit words, folds the carry, and returns the complement in hexadecimal.
Limits
- TCP/IP Checksum Digest Calculator: It does not construct the TCP pseudo-header from IP addresses.
- TCP/IP Checksum Digest Calculator: The implementation performs one carry fold; independently validate unusual or long inputs.