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Zawy’s Alternating Timestamp Attack

Zawy’s Alternating Timestamp Attack

Posted on: August 13, 2024 20:07 UTC

The discussion centers on the intricacies of blockchain timestamp management, specifically addressing the relationship between Maximum Time Past (MTP) and Future Time Limit (FTL) controls within the network.

The conversation opens with an acknowledgment of a misunderstanding regarding the potential to eliminate the need for MTP by implementing strict block time limits. It's clarified that without enforcing future timestamp limits, a network becomes vulnerable to attacks where timestamps could be manipulated significantly, suggesting a scenario where an attacker might extend the timestamp by an average of 40 minutes, potentially requiring a dominant control of the network indefinitely.

Further exploration into the topic reveals a proposal that a properly enforced FTL could implicitly ensure what the author refers to as a Past Time Limit (PTL) on every block. This means that if miners and nodes enforce a rule against accepting blocks timestamped too far into the future relative to their own, it would naturally prevent the acceptance of dishonestly timestamped blocks. This approach suggests a more indirect method of maintaining honesty within the block production process without explicitly naming it as such.

The conversation then shifts to a critique of broad consensus rule changes within the blockchain network. The initial claim that sweeping changes to consensus rules were theoretically "better" is walked back, acknowledging the inherent dangers and implementation challenges associated with wide-ranging adjustments to the network's operational rules. The focus on tangents and theoretical improvements stems from a personal interest in exploring potential hacks or solutions to perceived problems within the current system, like the dissatisfaction with how the FTL is enforced by miners.

A realization is reached that a rigorously enforced FTL effectively acts as a PTL, streamlining the enforcement mechanism by focusing on future limitations but indirectly controlling past timestamp integrity. This epiphany addresses a long-standing discomfort with the existing enforcement mechanisms for timestamps within the blockchain, proposing a more stringent and logical application of the FTL that could theoretically obviate the need for an MTP by ensuring all nodes acknowledge any dishonesty in ancestor timestamps exceeding a 2-hour future threshold. However, this is not posited as an outright recommendation, but rather a conceptual argument highlighting a potential path toward more robust timestamp validation practices within blockchain networks.