Understanding the Difference in SHA256 Hashing Between Delphi and Node.js

Explore the critical differences in SHA256 hashing between Delphi and Node.js, and learn how to generate consistent hash outputs across both platforms.
---
This video is based on the question https://stackoverflow.com/q/66722711/ asked by the user 'zorgo' ( https://stackoverflow.com/u/14074030/ ) and on the answer https://stackoverflow.com/a/66723223/ provided by the user 'fpiette' ( https://stackoverflow.com/u/189103/ ) at 'Stack Overflow' website. Thanks to these great users and Stackexchange community for their contributions.

Visit these links for original content and any more details, such as alternate solutions, latest updates/developments on topic, comments, revision history etc. For example, the original title of the Question was: Difference in SHA256 between Delphi and Node.js

Also, Content (except music) licensed under CC BY-SA https://meta.stackexchange.com/help/licensing
The original Question post is licensed under the 'CC BY-SA 4.0' ( https://creativecommons.org/licenses/by-sa/4.0/ ) license, and the original Answer post is licensed under the 'CC BY-SA 4.0' ( https://creativecommons.org/licenses/by-sa/4.0/ ) license.

If anything seems off to you, please feel free to write me at vlogize [AT] gmail [DOT] com.
---
Understanding the Difference in SHA256 Hashing Between Delphi and Node.js

Are you facing discrepancies between SHA256 hash outputs when generating hashes in Delphi compared to Node.js? This issue can be frustrating, especially when trying to ensure consistency across applications. In this guide, we will investigate the differences in SHA256 hashing between the two programming environments and explain how to achieve the same hash output for identical inputs.

The Problem: Inconsistent Hash Outputs

When using the password 123abc, the following code snippets yield different hash outputs in Node.js and Delphi:

Node.js Code

[[See Video to Reveal this Text or Code Snippet]]

Delphi Code

[[See Video to Reveal this Text or Code Snippet]]

As we can see, the hashes generated from the same password are not the same. This leads us to the core question: Why different? What did I do wrong?

The Solution: Achieving Consistent Hash Outputs

To ensure that Delphi produces the same output as Node.js, we need to adjust how we generate the hash in Delphi. Here’s a detailed explanation of the required change.

Necessary Change in Delphi Code

Instead of obtaining a hash string, you need to work directly with bytes and encode those. The correct Delphi code to achieve a consistent hash value is:

[[See Video to Reveal this Text or Code Snippet]]

Why This Works

Byte Output vs. String: The original Delphi code was converting the hash to a string format right off the bat. This led to a different interpretation of the data compared to the byte output of the Node.js hashing method. By using GetHashBytes, we ensure that we are always working with the raw byte data.

Base64 Encoding: After obtaining the byte output, we then properly encode it to base64, matching how Node.js does it. This ensures both environments produce the same final string representation of the hash.

Key Points to Remember

Always convert the hash output directly to bytes before encoding.

Pay attention to the encoding techniques used in both environments to prevent discrepancies.

Consistency in converting data types before hashing can greatly affect the output results.

Conclusion

In conclusion, while working with cryptographic functions like SHA256 in different programming environments, it is crucial to adapt the methodology accordingly to ensure consistent results. By implementing the changes mentioned above in your Delphi code, you should now be able to generate hashes that match those produced in Node.js, thereby achieving harmony between your applications.

Through understanding the underlying mechanics of how hashing works in both languages and the importance of working with the correct data types, you can avoid common pitfalls in cryptography. Happy coding!

Видео Understanding the Difference in SHA256 Hashing Between Delphi and Node.js канала vlogize