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by oblio 64 days ago
Why double sha256?
2 comments
haakon 63 days ago
The disappointing truth is that we simply don't know. Satoshi never explained it. For SHA-2 it can be used as a mitigation against length-extension attacks¹, and this seems like the most likely explanation, but it's just speculation.

¹ https://en.wikipedia.org/wiki/Length_extension_attack

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vscode-rest 63 days ago
Would length extension impact bitcoin? The messages aren’t secret afaik.
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vscode-rest 63 days ago
a that’s the botcoin hashing algorithm.
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oblio 63 days ago
I figured that part out, I wonder why it's being doubled.
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vscode-rest 63 days ago
That was the way satoshi wanted it. No other explanation is known.
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