Ah, I misunderstood your intention. That makes it clearer to me, thanks :) And I agree with you fully, in particular that this idea doesn't increase the guarant

Ah, I misunderstood your intention. That makes it clearer to me, thanks :) And I agree with you fully, in particular that this idea doesn't increase the guarantees or cryptographic assurances that you have in any real way. Then again I could envision it as being useful if you're stuck in a particular situation in which your use of hash function is mandated by something out of your control. If I was forced to use plain SHA1 (or god help me, MD5) for handwavy legacy reasons, throwing something like this in might help me sleep better at night. Would I ever use it? Probably not. But I think it's a cute hack that could be useful under the right (wrong?) circumstances.