[introduction_banner title=”Multi-Layer Structure” overview=”Overview”]
Origins on Bitcoin and zk-SNARKs
[introduction_details details=”When initially launching the blockchain, we selected a foundation with the longest proven track record of security, reliability, and decentralization: Bitcoin. The intrinsic data integrity of Pastel is heavily based on the Bitcoin codebase, and the project has a similar orientation towards mining-based proof-of-work and maximum decentralization.”] [introduction_details details=”We designed PSL to be the native cryptocurrency on the Pastel Network which can be used to transfer and store value in a similar way as Bitcoin. However, PSL also has a special use within the system: to allow participants to securely register and store their assets on the Pastel Network. In this case, PSL is essentially a version of Bitcoin as the core cryptocurrency layer, with the rare asset-related functionality built directly on top. This is done by encoding the collectible-related data into special transactions using the coin itself. The benefit of this unique design is that the data written in this way inherits all the security properties of the Bitcoin-like cryptocurrency, providing a solid foundational layer.”] [introduction_details details=”Rather than develop this ticket system directly on top of Bitcoin, we determined that it was beneficial to add the cryptographic innovation represented by the zk-SNARK system introduced by Zcash, which allows for provably secure “shielded†(private) transactions that can be validated by the network without disclosing the receiving address. Aside from shielded transactions, Zcash is mostly similar to the Bitcoin codebase with various tweaks, most notably using Equihash as the Proof-of-Work algorithm rather than the SHA-256 algorithm used in Bitcoin.”]
The company behind Zcash raised significant amounts of venture funding and was able to hire some of the brightest minds in cryptography, as well as retain several leading third-party security researchers to conduct
detailed security audits . The feedback of all these audits was then integrated in the system, hardening it in a way that goes well beyond the standard of care and rigor of 99% of cryptocurrency projects. That is why we decided that the Zcash codebase (as it existed in mid-2018) was the best starting off point for the Pastel codebase.
High-Level Ticket System
[introduction_details details=”Once we developed this way of abstracting files as low-level coin transactions using a Bitcoin-like system, we created a system of a higher-level series of tickets to perform all of the necessary NFT-related information on the network. We designed a system that can store such information to the blockchain using UTXOs directly in a high-performance, memory backed database. We leverage Pay-to-Fake-Multisig, or P2FMS, as the method to write data of any kind to the blockchain, as it has been optimized for the highest level of storage efficiency while using the UTXO set. We then represent the underlying information in a simple and secure format, which can be easily transmitted and subsequently signed by relevant nodes on the network.”] [introduction_details details=”The benefit of this system is that it provides a powerful and generic framework for encapsulating various sorts of structure and functionality. It is analogous to the difference between a high-level programming language like Python and low-level machine code.”]
We design various tickets to implement all required functionality. For example, we make a ticket for generating a new identity on the Pastel Network creating a PastelID, which consists of a public and private key (specifically, we use the EdDSA scheme with the Ed448 curve). This allows artists and collectors to establish a unique identity in the system, where they can sign transactions using their private key known only to them, and anyone in the network can verify that a transaction or message is authentic by checking the signature against the public key. This is critical, because in a decentralized system, anyone can try to be an imposter and put their “name†in the system as, say, Banksy. But with the PastelID system, the real Banksy could share his PastelID public key on his website or social media accounts, and everyone could then see if an artwork is a genuine Banksy, because only the real Banksy would be able to sign the artwork with a valid signature.
[introduction_details details=”Once we have identity establishing tickets in place, we turn to artwork registration tickets. These are tickets that contain various textual metadata fields related to a given artwork, such as:”]
- The name of the user
- The PastelID public key of the creator (this is what is used by the network to securely establish the identity of users)
- The name of the NFT and the number of rare copies of the NFT that the creator wants to create
- The file hash of the corresponding file for the NFT
- A robust visual fingerprint of the file used for duplicate detection
- The creator’s digital signature that proves cryptographically that the work is authentic
Supernodes
To handle the requirements of running a purpose-built, digital art cryptocurrency system while preserving maximal decentralization and ensuring that the system is scalable over the long term, we leverage the concept of a Supernode. The construct for Supernodes was based on the Masternode concept pioneered by the Dash cryptocurrency project, which was introduced in January of 2014. Supernodes represent an important extension of the core ideas of the Bitcoin system and provide a large amount of additional power and flexibility. Rather than having every full network node in the Pastel system independently verify and handle all the functionality of the system, we have a class of special Supernodes which are dedicated, high-performance machines that can handle the demanding storage and computational requirements of verifying and serving digital NFT files.
[introduction_details details=”Supernodes are powerful servers backed by collateral held in PSL and are designed to provide advanced services, verification, and governance on the Pastel blockchain. Anyone around the world can launch their own Supernode – all they need is a fast, internet-connected computer, a modest level of technical knowledge for set-up, and 5,000,000 PSL to serve as collateral. This structure ensures that the system remains fundamentally permissionless: the user does not need to ask anyone’s permission to run a Supernode. The network can continue to achieve the decentralization of Bitcoin, with the capability of performing more work and being much more flexible. It is also certainly more decentralized than the centralized mechanisms relied upon as a crutch on Ethereum-based NFT projects.”]
[introduction_details details=”The other benefit of Supernodes is that they create a healthy financial alignment between the custodians of the machines that operate the network and the owners of PSL coins, which creates a virtuous cycle of incentives. Supernode operators are provided with 20% of the block reward and are also given the opportunity to vote on up to 10% of the remaining block reward to fund community initiatives to support the Pastel ecosystem. Key PSL stakeholders have a direct incentive to make sure their Supernode is operating properly and not damaging the system.”]
[introduction_details details=”We have also designed various mechanisms to detect, prevent, and harden against attack vectors. Furthermore, the system tracks the reputation of nodes over time in a decentralized way so that nodes observed manipulating or damaging the network can be voluntarily banned or ignored.”]
Trustless Approach
[introduction_details details=”This approach of not trusting any network nodes, but instead always requiring multiple, randomly selected nodes to do computations and compare results independently in order to reach a secure consensus, is pervasive across the Pastel project. Supernodes are constantly checking up on each other to ensure that all other Supernodes are keeping up with their obligations to perform in the network promptly and accurately. For example, Supernodes periodically challenge one another to prove that they are really storing the file chunks that they are supposed to be storing. If the challenged Supernodes is unable to respond to the challenge quickly enough, it effectively costs them reputation points in the system. If their reputation gets too low, they are penalized by the network by excluding them from participating in the Supernode block rewards for a certain number of blocks.”] [introduction_details details=”The goal of this is to make the system such that, in order for an attacker to disrupt the network, they would need to control a high enough percentage of all Supernodes so that they could reliably count on all of the randomly selected Supernodes for each block being under their control. If any of the selected Supernodes are “honest†then their results will disagree with the malicious nodes and the network can reject the transaction as being invalid.”][information_readmore title=”Introduction” link=”https://pastelnetwork.wpengine.com/overview/introduction/”] [information_readmore title=”Core Features” link=”https://pastelnetwork.wpengine.com/overview/core-features/”] [information_readmore title=”Built for Builders” link=”https://pastelnetwork.wpengine.com/overview/built-for-builders/”]
[information_readmore title=”User-Friendly Experience” link=”https://pastelnetwork.wpengine.com/overview/user-friendly-experience/”]