There are 7 proprietary innovations that deliver Partisia Blockchain’s complete Layer 1+2 Blockchain. In this blog we present the third innovative feature — the token bridge — we call it, Hermes.
For an overview of all of the 7 features see the Zeus blog. We present each of the 7 innovations with a unique post leading up to TGE on May 31, 2022.
The evolution and innovation around blockchain technologies has resulted in a variety of different blockchain networks with different strengths and weaknesses. This development will likely continue and interoperability and token bridges as the most prominent instrument, has become a major value creator in the blockchain ecosystem. Designing secure token bridges is, however, a significant challenge as values are moved out of the security model backing the involved tokens.
Partisia Blockchain has designed a new type of token bridge that addresses existing weaknesses. This is an important innovation as any use of Partisia Blockchain involves external coins, hence, token bridges are part of the very backbone of the blockchain network. We believe this is a superior foundation for a more solid token bridge.
The Partisia Blockchain token bridge model utilizes a number of cryptographic tools and basic economic principles. The core basic principle is a collateralized token transfer represented 1 to 1 across two independent blockchain networks, which basically mimics a double booking system that has proven its worth since the Medici Bank in the 14th century. The challenge is to simultaneously represent and work with states from two independent blockchains as efficiently and as securely as possible. The token bridge is illustrated and briefly described below.
The illustration captures the three main components of the token bridge around the two basic operations — depositing and withdrawing values.
The first part is the double bookkeeping principle within regularly expiring epochs: The process ensures that the information is persisted on both blockchains and establishes a straightforward auditability that is easily accessible by all users and node operators. Deposit and withdrawal is managed by a small set of independently selected Oracle nodes — the small Oracle — in expiring epochs as further described below.
The second part is the collateralized bridging within the regularly expiring epochs: The small Oracle consists of Oracle nodes with sufficiently available MPC tokens that function as locked collateral during an epoch. The epoch expires when the small Oracle runs out of MPC tokens as collateral. In the following epoch any holder of MPC tokens can stake to run a dispute in case of fraud.
The third part is a secure selection of small Oracles: An MPC based signature scheme operated by the large Oracle (i.e. all available baker nodes) ensures that the selection of the next small Oracle matches the security of the consensus model. The large Oracle is also responsible for delegating the job of mirroring the identity of the members of both the small and the large Oracle to the partner chain. With that in place, the double bookkeeping is securely established.
For more details, please checkout the yellow paper and software documentation.
Please let us know what you think and stay tuned for the next blog post about the zero-knowledge layer, called Athena.
Thank you to everyone in our community for your support!
Partisia Blockchain Team
There are 7 proprietary innovations that deliver Partisia Blockchain’s complete Layer 1+2 Blockchain. In this blog we present the second innovative feature — the sharding model — we call it Iris.
For an overview of all of the 7 features see the Zeus blog. We present each of the 7 innovations with a unique post leading up to TGE on May 31, 2022.
The so-called blockchain trilemma is all about the difficulties in designing a blockchain that can scale to handle any number of transactions without hampering secure decentralization. The key to unlocking this challenge is sharding, which is the art of parallelizing consensus without compromising security:
Partisia Blockchain solves the blockchain trilemma through sharding involving all baker nodes across all shards as a genuine layer 1. This way, sharding does not impact the Poseidon provable consensus model and hence neither diminish decentralization nor the overall threshold security model.
An illustration of the scalable block creation where each shard creates verifiable blocks according to the consensus model presented in the Poseidon blog is provided below. The consolidated blockchain shows how the sharding scales linearly in the number of shards i.e. a blockchain running with three shards can handle three times as many concurrent transactions as a blockchain running without sharding. To see this, note that the consensus process, including the time consuming propagation of messages, is done in parallel and independently across shards. A governance shard keeps track of the shards and distributes the block creation work across the independent shards. Also, the security model ensures that all new nodes are properly represented across all shards and thereby validate every transaction.
This way, the capacity of the Partisia Blockchain can be scaled up to meet any number of transactions per second (TPS). The capacity of a shard is roughly 1,000 TPS and a new shard is just one transaction away. Even in the rare case of a time consuming full BFT reset on one shard, the workload allocated to other shards and the impact on the capacity of the entire blockchain will be marginal only.
Sharding is an integrated part of the initial version of the Partisia Blockchain and will gradually be developed to dynamically adjust for throughput by spinning up new shards on demand exactly as cloud computing allows dynamic load balancing.
For more details, please checkout the yellow paper and software documentation.
Please let us know what you think and stay tuned for the next blog post about our collateralized token bridging, called Hermes.
Thank you to everyone in our community for your support!
Partisia Blockchain Team
There are 7 proprietary innovations that deliver Partisia Blockchain’s complete Layer 1+2 Blockchain. In this blog, we present the first innovative feature — the consensus model — we call it, Poseidon.
For an overview of all of the 7 features see the Zeus blog. We present each of the 7 innovations with a unique post leading up to TGE on May 31, 2022.
A core requirement for any blockchain is to establish trustworthy consensus about the shared distributed ledger holding information like transactions ordering and smart contracts. Only this way can blockchain replace intermediators in the economy and simplify coordination of tasks, data and trades. Establishing consensus in distributed computing systems has been studied for decades. Although there is no perfect game theoretical solution, the most trusted approach is the so-called Byzantine Fault Tolerance model (BFT). The name comes from the “Byzantine generals problems” where independent generals need to establish common knowledge to succeed. The main problem with naïve BFT is that it is too slow and hampers scalability. Partisia Blockchain, however, provides scalability with BFT through an Eager FastTrack consensus model.
On Partisia Blockchain, transactions are added to the ledger via immediate block creation and executed node by node immediately after signing. Consensus is established in the P2P network where signatures are propagated and aggregated. When a node achieves signatures from ⅔ of all nodes or more, a Proof-of-Justification (PoJ) is established, and the node moves on to evaluate the next block immediately. PoJ also finalizes the transactions in the previous block. Since this process happens as fast as information travels through the P2P network, we call it lightning fast finalization. In rare cases, the FastTrack approach may fail to reach consensus. If this happens, the protocol reset the blockchain through a full BFT style consensus and restart the FastTrack consensus, as illustrated below. This way, the consensus protocol achieves finalization among ⅔ of all nodes as fast as possible, while still backed by a BFT style consensus.
Combined with sharding, scalability is complete as a reset on one shard happens independent of the other shards, but more about that in the next blog on “Iris — complete sharding”.
Another core problem solved by Partisia Blockchain is to ensure that the validators actually construct and validate transactions. This is a general problem for validation based consensus like Proof-of-Stake, which was solved in the Proof-of-Work protocol where miners don’t get paid if they work on a wrong version of the blockchain. A validator on the Partisia Blockchain, however, has to construct a cryptographic proof prior to signing a block. The cryptographic proof is node-specific and proves that the node has signed the executed version of the blockchain.
For more details, please checkout the yellow paper and the software documentation.
Please let us know what you think and stay tuned for the next blog post about our Sharding technology, called Iris.
Thank you to everyone in our community for your support!
Partisia Blockchain Team