fix(avm)!: add std multi-row computation constraint#21718
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IlyasRidhuan wants to merge 2 commits intomerge-train/avmfrom
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fix(avm)!: add std multi-row computation constraint#21718IlyasRidhuan wants to merge 2 commits intomerge-train/avmfrom
IlyasRidhuan wants to merge 2 commits intomerge-train/avmfrom
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This was referenced Mar 18, 2026
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Please apply the standard recipe.
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| pol commit round_inv; | ||
| #[KECCAK_SEL_ROUND_NON_ZERO] | ||
| round * ((1 - sel) * (1 - round_inv) + round_inv) - sel = 0; | ||
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I think this ended up being redundant as derivable form the new multi-row constraints (specifically SEL_ON_START_OR_END)
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For
sel = 1 => round !=0- #[START_AFTER_LATCH] ensures every computation block begins with start=1
- start * (round - 1) = 0 forces round = 1 on the first row
- #[KECCAK_ROUND_INCREMENT] increments round by 1 each subsequent row within the block
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For
round != 0 => sel = 1- sel_slice_write == 1 ==> round == 24 (by #[WRITE_TO_SLICE] perm)
- sel_slice_write = sel_no_error * end, the new #[SEL_ON_START_OR_END] guarantees end = 1 => sel = 1 as well
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I agree. Good simplification.
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| // write: #[WRITE_TO_SLICE] is a permutation requiring round == 24 on a row with sel == 1. | ||
| // ==== MULTI-ROW COMPUTATION SELECTORS ==== | ||
| // See recipe: https://github.com/AztecProtocol/aztec-packages/blob/next/barretenberg/cpp/pil/vm2/docs/recipes.md#contiguous-multi-rows-computation-trace | ||
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I would move the declarations for start and end here with their boolean conditions.
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Adds the standard multi-row constraint to prevent valid computation from being maliciously terminated midway.
Note there there is no vulnerability that this was fixing.
[WRITE_TO_SLICE]is a permutation requiringround == 24so a malicious prover could not invalidly terminate the keccak computation. This is just to standardise multi-row constraints.