The choice of crosschain bridges for DeFi users is focused on official bridges for public chains, MulticoinChain, Hop Bridge and Synapse Protocol, which are self-developed crosslink bridges. This article focuses on the Synapse Protocol, the newest addition to the cross-chain bridge.

Firstly, let's understand the asset cross-chaining approach.

1. Locked Casting Model: The Synapse Bridge locks the asset in the original Chain A and transfers it to Chain B to issue a redeemable certificate of the original Chain A asset, i.e. the cross-chain asset, thus completing the cross-chain transfer of the asset value. The minor disadvantage of this model is that it is difficult to meet user requirements in terms of efficiency and cost, and often only a small number of public chains (e.g. Ether to new chains) are linked in order to introduce mainstream cross-chain assets to the new chain, and are usually officially supported or developed directly by the new chain.
2. Two-way pool model: A pool of funds is set up in advance on both sides of the bridge, one pooling a large amount of original assets from the original chain and the other pooling cross-chain assets already issued by the official bridge. The minor disadvantage of this model is that it requires the use of cross-chain assets already issued by the official bridge and can only be deployed once the official bridge has been established.
3. ICP Canister Smart Contracts (not yet available): Enables Token A (BTC) to be held, accessed, traded and forwarded to the A-chain (BTC) mainnet, directly integrating with the A-chain (BTC) mainnet and giving smart contracts to the A-chain (BTC) mainnet.

The first two cross-chain approaches are currently dominant on the chain, with Synapse Protocol taking the first approach.

Synapse Protocol is an upgrade from the anonymous cross-chain liquidity protocol Nerve Finance (Nerve $2M seed round led by Three Arrows, CMS Holdings and Alameda Research) on the former BSC.

Synapse uses cross-chain Multi-Party Computing (MPC) validators and Threshold Signature Solutions (TSS) to support assets, smart contract calls and more, linking different block chains for easy and secure interoperability; developers can also build true cross-chain applications including cross-chain DEX, lending platforms, margin systems, derivatives markets, revenue aggregators and more.

Bridging and interchange between all major EVM compatible chains is currently supported, including Ethereum, BSC, Polygon, Avalanche, Arbitrum, Optimism, Aurora, Boba Network, Moonbeam, Moonriver, Fantom and Harmony.

Synapse Protocol currently has $8.35B in Total Bridge Volume and $885.12M in TVL.

Token: $SYN - Synapse Network Governance token for the cross-linked bridge ecosystem.

M.cap: $362M / 170M

FDV: $515M / 250M

Release: ~415k $SYN per week

Governance Token $SYN Features.

Voting governance (anyone with more than 50,000 $SYN holders can submit a snapshot proposal to SynapseDAO).

Protocol Fee Governance (half is credited to the DAO vault and the other half is used to repurchase $SYN).

Verifier bonuses ($SYN can be used as a subsidy to compensate verifiers for GAS consumed on Ether).

Liquidity Provider Bonus, etc.

Cross-chain AMM

When the Synapse network receives confirmation of an event on the source chain, the required wrapper assets can be cast directly on the network without authority. However, users often wish to receive native assets from another target chain (i.e. ETH, DAI, etc.) that is connected to but not identical to the Synapse network. In this case, Synapse AMM is required to execute the necessary transactions during the bridging process, by using a stable exchange algorithm to price the transactions, and by stimulating asset rebalancing during the exchange and bridging process.

1. $nUSD is a cross-chain stablecoin that is fully backed by the NEXUS stablecoin liquidity pool on Ether, including $DAI, $USDC and $USDT.

When a stablecoin is bridged between Synapse-enabled chains, the funds are automatically converted to $nUSD and bridged to the destination chain. Once the bridge is successful, this $nUSD can be automatically exchanged to that chain's stablecoin using the local nUSD pool.

Synapse has two types of $nUSD pools: NEXUS pools on Ethereum, and $nUSD pools on Aurora, Avalanche, BNB Chain, Boba, Fantom, Harmony and Polygon. The NEXUS pool is a stablecoin triple pool consisting of $USDC, $USDT, and $DAI.

2.$nETH is an ETH-linked cross-chain asset, fully backed by Ether's nexus ETH liquidity pool, which is (currently) made up of only ETH.

$nETH is used to enable fast bridging of ETH to L2 networks such as Arbitrum, Boba and Optimism.

Synapse Chain

With the launch of the Synapse Chain (also known as the Archean phase), Synapse will no longer require AMM pools on each chain, but will be able to replace them with liquidity on the Synapse Chain, thereby increasing capital efficiency and reducing the release of $SYN.

In addition, the Synapse chain will allow developers to build cross-chain liquidity on top of Synapse and create a new generation of protocols that can interact with assets, regardless of where they are located on the blockchain. In addition to the native L1 ecosystem including the usual DeFi products (e.g. DEX, lending platforms, derivatives), the Synapse chain will have new cross-chain capabilities.

In the future of multi-chain crypto-finance, cross-chain protocols alone as public chains connecting the various public chain ecosystems can better and more securely help users to bridge the transfer of their assets! This is why Synapse Chain, a cross-chain public chain, is called Layer 0 of DeFi Roc High School.

Roadmap

Hadean: The current stage of the Synapse protocol is a period of growth and rapid development, with many measures in place to ensure the secure deployment of new features.

Archean: will further enhance the decentralisation of verifiers, primarily through the introduction of the Synapse chain, with financial guarantees through Delegated Proof of Stake (DPoS). Verifiers and principals are incentivised through $SYN incentives and agreed fees. In order to maintain the integrity of individual verifiers, and the security of the network, they will be subject to a reduction in the $SYN they invest when they engage in negligent or malicious conduct, and agents will be subject to the same reduction as their chosen verifier. While the network should always strive to have as many individual verifiers as possible, allowing delegation is an important part of kick-starting the growth of the network while involving a large number of token holders in the network verifier process. Clearly a pure PoS mechanism is not feasible, as is the case with ETH 2.0 today, through liquidity derivatives, leading to various centralised or decentralised alternatives to delegated quotas. The Synapse chain will therefore create a cross-chain interoperable ecosystem, guaranteed by $SYN, connecting all chains.

Proterozoic: The Synapse DPoS chain continues to grow and strengthen. By integrating zero-knowledge proofs, the network will be further decentralised, allowing any user to transit and settle cross-chain transactions. In addition to this, the Synapse protocol team is also developing the UTXO-EVM and Rust-EVM bridges. In the near future, these bridges could both become significant drivers of transaction volume, allowing for exchanges as well as transfers to the Bitcoin and Polka chains.

References: 1. https://forum.synapseprotocol.com/d/7-implement-syn-staking-in-preparation-of-pos-synapse-chain-launch

2. https://docs.synapseprotocol.com/

3. https://mirror.xyz/interndao.eth/pseI1ESiTzz5Ba1yCGwgPQqXCyrjSa4NaskWC00UMjU