Information integrity of blockchain and related technologies

Glossary

Term definitionsBlockchainA structure consisting of blocks of data, where each block contains a cryptographic hash of the previous block, creating a tamper-proof chain of data. BlockA single record in a blockchain that contains data and a hash of the previous block. Hash functionAn algorithm that converts input data of arbitrary length into output data of fixed length. Cryptographic hash functions are used to ensure the integrity of data. Proof of Work (PoW)A mechanism that requires a large amount of computing power to solve mathematical problems, used to create new blocks in a blockchain and ensure its security. Proof of Stake (PoS)A mechanism that relies on the amount of cryptocurrency held by a user to verify transactions and create new blocks. Verification Signature Key (VSK)A key pair generated by a data processing node and used to sign information, consisting of a public key and a private key. The private key in the VSK pair used for signing, known only to the data processing node. The public key in the VSK pair used for verifying signatures, which can be distributed publicly. Commit Signature Key (CSK)A key provided by the satellite owner to the committer to sign commit commands, with a certain validity period and a limited number of uses. Chain Initialization Command (CIC) Command used to initialize a new blockchain on a satellite. Payload Commitment Command (PCC) Command used to extend an existing blockchain by adding a new block. Chain State Confirmation (CSC) Message sent by a satellite containing information about the state of a blockchain, such as the genesis block and the latest block. Merkle Tree A data structure that allows the integrity of a large number of data fragments to be verified efficiently, commonly used to store transactions in a blockchain. Merkle Tree Root Hash The hash value of the top level of a Merkle Tree, representing the integrity of all underlying data. Short Answer Question

Why is the security of the last block of a blockchain so important?

The security of a blockchain relies on its tamper-proof nature, thanks to the cryptographic link between each block and its previous block. The security of the last block is the most critical, as it is the only block that is not protected by subsequent blocks. If the last block is compromised, the integrity of the entire blockchain is questioned.

What role does VSK play in this system?

VSK (Verified Signing Key) is used to ensure the integrity of information transmitted from the satellite to the ground system. Each satellite generates a unique VSK pair, where the private key is stored only on the satellite and the public key is distributed to authorized users. The satellite signs the transmitted data using its private key, while the ground system verifies the integrity of the information using the corresponding public key.

What role does the deployment indicator play in VSK generation? Why is this important?

The deployment indicator is a signal or event that indicates that the satellite has been successfully deployed to its intended orbit. The VSK generation process is designed to start only after receiving this signal. This is critical for security because it prevents premature key generation during satellite launch or transportation, minimizing the risk of key compromise.

Please explain the purpose of the Chain Initialization Command (CIC) and how it is processed.

The CIC is used to create a new blockchain on the satellite. It typically contains a data payload of a new genesis block along with the signature of the owner. Upon receiving the CIC, the satellite verifies its authenticity and, if the payload is unique among all existing blockchains, allocates a memory slot for the new chain, stores the genesis block, and sends a Chain State Confirmation (CSC) to the ground system.

How does the Payload Commit Command (PCC) differ from the CIC?

Unlike the CIC, which creates a new blockchain, the PCC is used to add new blocks to an existing blockchain. It contains the data of the new block, the hash of the previous block, and the signature of the submitter. After receiving the PCC, the satellite verifies its signature and the hash of the previous block. If the verification is successful, the new block is added to the corresponding blockchain and the CSC is sent to the ground system.

Briefly describe the role of the Merkle tree in the blockchain.

The Merkle tree is used to efficiently represent and verify the large amount of data stored in the blockchain. It is a binary tree structure in which each leaf node represents a data block and each non-leaf node represents the hash of its child node. The Merkle tree root hash is stored in the block header, allowing users to efficiently verify whether a specific data block belongs to the blockchain.

What is the difference between Protocol 0 and Protocol 1?

Protocol 0 describes how a single satellite manages a blockchain, focusing on tamper-proofing and data integrity. Protocol 1 defines how data from multiple satellites can be aggregated into a "virtual blockchain" to provide greater security and flexibility.

What is the role of the virtual witness in Protocol 1?

A virtual witness is a simulated process that runs on the ground system to track and verify the state of the Protocol 1 virtual blockchain. Each virtual witness is associated with a specific satellite and independently rebuilds the virtual blockchain based on the Protocol 0 data received from that satellite.

Why is this system more sustainable than Proof of Work (PoW) systems?

Unlike PoW systems, which require a lot of computing power and energy consumption, this system relies on physically inaccessible satellites and efficient cryptography to ensure the security of the blockchain. This approach eliminates the need for energy-intensive mining, making it more environmentally friendly and sustainable.

In addition to cryptocurrency, what other fields can this system be applied to?

The system has a wide range of potential applications, including but not limited to: secure document storage and verification, supply chain management, digital identity, intellectual property protection, voting systems, and any application scenario that requires tamper-proof and trusted data records.

Paper Title

Discuss the advantages and disadvantages of using physically inaccessible platforms in blockchain technology, focusing on security and scalability.

Compare and contrast Proof of Work (PoW), Proof of Stake (PoS), and the proposed satellite-based blockchain security mechanism, analyzing their advantages and disadvantages, potential application scenarios, and future development trends.

How does the virtual witness mechanism in Protocol 1 enhance the resilience and fault tolerance of the system? Discuss different attack vectors and how the system mitigates these threats.

How can the satellite-based blockchain system described in this paper facilitate data sharing and collaboration between different entities without relying on a trusted third party? Give examples of potential use cases.

In the long term, how will advances in quantum computing affect the security of the satellite-based blockchain system proposed in this paper? Discuss potential challenges and coping strategies to ensure the long-term viability of the system.