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copied!<p>I would split this into two problems.</p> <ol> <li>How do you get the same serialized string in both JavaScript and Python?</li> <li>Which byte array hash function should you use? It must be an established algorithm with identical implementations in both JavaScript and Python.</li> </ol> <p>Use (1) to get two strings, then UTF8 encode, then use (2) to get hashes.</p> <p>Since (2) is straightforward, I'll only address (1).</p> <p>There are multiple facets to the problem of making sure the two JSON strings you generate are identical.</p> <ul> <li>You'll want to used unformatted JSON (no extraneous spaces, tabs, or newlines).</li> <li>null values must be treated identically. Some serializers will by default throw away a dictionary key-value pair if the value is null.</li> <li>Ordering of key-value pairs within a dictionary must be consistent.</li> <li>JSON number serialization should be consistent. For example, you can't have integer one serialize as <code>1</code> on one side and <code>1.0</code> on the other. (This probably won't be as big of an issue however.)</li> <li>The string encoding should be the same for both. JSON allows serialization to Unicode text, only mandating that <code>"</code> and <code>\</code> be backslash-escaped in JSON strings. Most serializers do more than necessary, however, and reduce almost all Unicode characters to the <code>\uXXXX</code> equivalent. See <a href="http://json.org/" rel="nofollow">json.org</a> for the details on JSON string encoding. One way to remove all ambiguity is to only escape when absolutely necessary.</li> </ul> <p>You'll want to make sure all of these are matched between JavaScript and Python. Most JSON serialization libraries I've used provide configuration hooks for all of the things I mention in the list above. Unfortunately, I'm not very familiar with the JavaScript or Python libraries.</p>

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