The PascalCoin developers just announced their plan of an upcoming implementation of the Account Seal, a groundbreaking component of the cryptocurrency’s SafeBox design. Before we dissect the implications of the Account Seal, let’s first go back to square one and take a look at the SafeBox’s genesis to better understand how everything began and would end.

In late 2016, Albert Molina released the first proof of concept for PascalCoin, a cryptocurrency that retains all account balances within the SafeBox while deleting older blocks’ extraneous memory. At first, this concept may not sound radically innovative but one would need to understand that this design was the first and the only blockchain checkpointing paradigm in the world in which nodes can prove they are on the most-work-chain without the infinite history.

Few drawbacks still existed for the original SafeBox design. For instance, a new node would need to first download the entire blockchain history before being able to delete older blocks. Herman Schoenfeld, one of the core PascalCoin developers, solved this issue with the release of V2 in which new nodes no longer need to download the entire blockchain history as an initial requirement before proving they are on the longest Proof-of-Work chain. This paradigm shift dramatically reduced the importance of archival nodes to PascalCoin’s network security for the better.

A distinction should be made between cryptographic integrity, the proof that the SafeBox is hashed correctly from block 0, and cryptographic security, the number of blocks that need to be re-mined in an attack. The SafeBox, as it currently stands, retains the full cryptographic integrity without needing to preserve the entire blockchain history which is revolutionary on its own. As for cryptographic security, the SafeBox currently retains 99% - not 100% - of the cryptographic security of a full blockchain due to the “state attack” vector. PascalCoin’s cryptographic security is still far more secure than the simple payment verification (SPV) security model and would be much more difficult to execute than a straightforward 51% double spending attack. Although this “state-attack” requires tremendous hashpower and is not feasible with the current network security due to how archival and semi-archival nodes would easily thwart this attack, it could pose an issue in a global adoption scenario (even if for causing short-lived/local SafeBox disruptions). More details on the “state attack” is explained in depth in the PascalCoin whitepaper.

Along with the infinitesimal loss of cryptographic security with the SafeBox, there is one other subtle drawback. A PascalCoin-based ecosystem especially a smart contract framework (e.g. sidechains) may benefit from having the ability to track operations beyond the 100-block-minimum that PascalCoin nodes retain, and so archival nodes may be queried in such a scenario. This situation introduces a trust-based model within a global adoption scenario where the full blockchain is beyond the storage of an ordinary node. Even though PascalCoin has relatively far less dependence on archival nodes, this issue still persists partially to a degree. It should be noted that this issue is fully present in every, if not all, cryptocurrency.

As it stands currently in V4, PascalCoin’s SafeBox model has two minor drawbacks:



• The presence of the (extremely unlikely) “state-attack” vector. This is unique to the SafeBox.



• The trust-based reliance of archival nodes for certain circumstances where the pathways – not the final destinations – of accounts are of interest. This is not unique to the SafeBox.

This is where the Account Seal comes in, slated for a V5 release. It is the final piece of the puzzle that would supercharge the SafeBox as the indisputable blockchain archetype. The Account Seal fully solves the two drawbacks above. Put simply, the Account Seal enables every PASA (PascalCoin account) to also function as its own blockchain. With this feature, a user would only require the current SafeBox to verify an account’s history, not the blockchain itself. This is achieved by including a hash-based link between PASA state-transitions, much in the same way to how blocks link in a blockchain. This link, called the Account Seal (or PASA Seal) is simply a hash commitment to the account’s prior state and the mutating operation which led to the current state at no additional Proof-of-Work cost since this link is pinned to SafeBox’s aggregate Proof-of-Work.

Armed with the Account Seal, the SafeBox is now invulnerable to the “state-attack” and does not rely on older blockchain history to prove the pathway of an account. At this rate, the SafeBox model will become an overwhelmingly powerful, de facto platform for blockchain applications thanks to its ability for:



• Instant, zero-fee transactions

• Theoretical limit of 72,000 trnasactions per second

• Infinitely scalable smart contracts

• Comprehensive anonymity

• Simple account numbers for addresses (e.g. 1000-84)

• Infinitesimal storage requirement for nodes

• And much more!

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