Fix v1 Autolykos zero pow_distance serialization to match sigma JVM#872
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Fix v1 Autolykos zero pow_distance serialization to match sigma JVM#872mwaddip wants to merge 1 commit into
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AutolykosSolution::serialize_bytes wrote the v1 PoW distance via BigUint::to_bytes_be(), which returns [0] for zero. The JVM's sigma/crypto/BigIntegers.scala asUnsignedByteArray drops BouncyCastle's length-1 guard, so it encodes zero as an EMPTY array. The Rust path emitted 01 00 where the JVM emits 00, diverging on the serialized header bytes (hence header id) and Global.serialize cost. Mirror asUnsignedByteArray exactly: empty bytes for zero, minimal big-endian otherwise (identical to to_bytes_be for all positive values). A real PoW distance is never zero, so this is an adversarial/degenerate edge with no mainnet impact, but a genuine consensus divergence in the serializer. Co-Authored-By: Claude Opus 4.8 (1M context) <[email protected]>
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AutolykosSolution::serialize_bytesencodes a v1 PoW distance of0as01 00(viaBigUint::to_bytes_be()→[0]), while the sigma JVM emits00.Sigma's
BigIntegers.asUnsignedByteArrayreimplements BouncyCastle but drops the&& bytes.length != 1guard, so a zero value strips to an empty array. The mismatch diverges on serialized header bytes (hence header id) andGlobal.serialize[Header]cost — a consensus split on the degenerate path.Fix: mirror
asUnsignedByteArray— empty for zero, minimal big-endian otherwise (identical toto_bytes_befor positived). A real PoW distance is never zero, so no mainnet impact; this closes the adversarial edge. Adds a regression test.