Exact source-envelope accounting for one affine round #
Original left and right source coordinates retain joint mass envelopes
through every actual observation. If S is the cardinality of all honest
and tampered short messages, the complete left total is multiplied by
S^2, and the complete right total by S^4. Opposite-side observations
preserve envelope totals exactly. Null conditional rows are included.
These finite bounds implement the transcript entropy accounting in Chattopadhyay--Liao, Theorem 6.1, printed pp.23--25: https://arxiv.org/abs/2110.12652. They neither supply nor assume a statistical security guarantee for the round's extractor calls.
The first right observation scales the original-left envelope by its message probability.
The original-right source is bounded by the copied envelope after its prefix masks are observed.
Actual prefixes copy the original-left envelope over their message alphabet.
The opposite-side prefix observation preserves the weighted original-right bound.
First right seeds and short-row masks preserve the original-left source bound.
The paired middle-right observation copies the original-right source envelope.
Actual short rows copy the original-left source envelope a second time.
The short-row observation preserves the weighted original-right bound.
The full actual transcript bounds the unchanged original-left source coordinates.
The full actual transcript bounds the unchanged original-right source coordinates.
The first right observation preserves the original-left envelope total exactly.
The actual prefix family charges one short-message alphabet to the left total.
Through the prefix stage, the right total pays only for its prefix-mask family.
The paired right message preserves the preceding original-left envelope total.
The paired right message gives a cubic short-message factor in the right total.
Through the actual short rows, the original-left total pays two short-message families.
Actual short rows preserve the cubic original-right envelope total.
The complete round multiplies the original-left envelope total by the square alphabet size.
The complete round multiplies the original-right envelope total by the fourth power alphabet size.
Nonnegative original-left envelopes remain nonnegative after the prefix stage.
Nonnegative original-right envelopes remain nonnegative after the prefix stage.
The middle-right update preserves the original-left envelope sign, including null rows.
The copied middle-right original-right envelope is nonnegative.
The original-left envelope remains nonnegative after the actual short outputs.
The original-right envelope remains nonnegative after the actual short outputs.
The full original-left envelope is nonnegative at every transcript.
The full original-right envelope is nonnegative at every transcript.
The honest and tampered short-message family has the exact Boolean cardinality.