Hot answers tagged sponge
As fgrieu pointed out, the constants are defined in terms of a binary Linear Feedback Shift Register. Because LFSRs can be represented very efficiently using standard logic gates they have been used for pseudorandom number generation computers for decades. They have fallen out of favor for use directly as secure stream ciphers due to advances in ...
I can at least point to how the constant are derived. Quoting the Keccak Reference This is not a rationale, and I confess that I do not quite get how we go from that to the values.
Section 4.3 of the paper Cryptographic sponge functions analyzes the Overwrite-mode for a sponge, which does just what you propose: instead of XORing the next part of the message into the non-hidden part of the state, replace the non-hidden part of the state by it. They show that it can be implemented on top of the Duplex mode (which outputs the non-hidden ...
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