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Co-authored-by: Derek Cofausper <256792747+decofe@users.noreply.github.com> Amp-Thread-ID: https://ampcode.com/threads/T-019d3f00-3838-7357-870f-e511f80eb152
Co-authored-by: Derek Cofausper <256792747+decofe@users.noreply.github.com> Amp-Thread-ID: https://ampcode.com/threads/T-019d3f00-3838-7357-870f-e511f80eb152
dankrad
reviewed
Mar 30, 2026
dankrad
reviewed
Mar 30, 2026
Overwrites to slots already nonzero in the current epoch use SSTORE-equivalent hot/cold pricing instead of the flat 40k. A nonzero value in the previous epoch only does not qualify — still incurs the 40k new-slot cost. Co-authored-by: Derek Cofausper <256792747+decofe@users.noreply.github.com> Amp-Thread-ID: https://ampcode.com/threads/T-019d3f00-3838-7357-870f-e511f80eb152
Storage key is uint16(epoch) ++ keccak256(sender || key)[0:30] in the precompile's own storage trie. Adds a full reference Solidity mock demonstrating the key derivation and epoch fallback logic. Co-authored-by: Derek Cofausper <256792747+decofe@users.noreply.github.com> Amp-Thread-ID: https://ampcode.com/threads/T-019d3f00-3838-7357-870f-e511f80eb152
EVM convention is to keep the low-order (rightmost) bytes when truncating hashes (e.g. address = keccak256(pubkey)[12:32]). Updated spec text from [0:30] to [2:32] to match — the Solidity mock was already correct. Co-authored-by: Derek Cofausper <256792747+decofe@users.noreply.github.com> Amp-Thread-ID: https://ampcode.com/threads/T-019d3f00-3838-7357-870f-e511f80eb152
uint16 wraps after 2^16 epochs (2^32 blocks). uint32 supports 2^32 epochs (2^48 blocks) before wrap-around, removing any practical lifetime concern. Hash truncation goes from 30 to 28 bytes (224 bits), still more than enough. Co-authored-by: Derek Cofausper <256792747+decofe@users.noreply.github.com> Amp-Thread-ID: https://ampcode.com/threads/T-019d3f00-3838-7357-870f-e511f80eb152
Co-authored-by: Derek Cofausper <256792747+decofe@users.noreply.github.com> Amp-Thread-ID: https://ampcode.com/threads/T-019d3f00-3838-7357-870f-e511f80eb152
Replaces the prefixed-key-in-single-account layout with separate accounts per epoch (PRECOMPILE_ADDRESS + n + 1). This lets nodes prune expired epochs by dropping entire accounts instead of scanning individual slots. Co-authored-by: Derek Cofausper <256792747+decofe@users.noreply.github.com> Amp-Thread-ID: https://ampcode.com/threads/T-019d3fed-b1f0-71ac-bbe2-1caeabc2bf51
dankrad
reviewed
Mar 30, 2026
dankrad
reviewed
Mar 30, 2026
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Adds TIP-1040: a precompile for epoch-scoped temporary key-value storage. Values are available for 2^16 to 2^17 blocks then automatically expire. Nodes can prune anything older than the previous epoch.
Key design points:
keccak256(sender || key)scoped peruint16(epoch)— sender-isolated, no cross-contract collisions.Prompted by: dankrad