🧵🧶This is summarization of few bridging protocols engineering the bright future of cross-chain messaging and interoperability - Connext Network & Nomad.

The boom of bridging protocols/project appeared in 2021, however many of the bridges were running at huge risk of funds being lost during the chain transfer. The first thing I want to point out is that still the risk remains and many funds were lost!!!

The basic explanation is below:

V. Buterin puts it aptly in his tweet:

“Now, imagine what happens if you move 100 ETH onto a bridge on Solana to get 100 Solana-WETH, and then Ethereum gets 51% attacked. The attacker deposited a bunch of their own ETH into Solana-WETH and then reverted that transaction on the Ethereum side as soon as the Solana side confirmed it. The Solana-WETH contract is now no longer fully backed, and perhaps your 100 Solana-WETH is now only worth 60 ETH. Even if there’s a perfect ZK-SNARK-based bridge that fully validates consensus, it’s still vulnerable to theft through 51% attacks like this.”

After pointing out the danger of the bridges, we need to be able to improve and create safer projects around the area because the future it seems to be cross-chain and the opportunities hidden between them!

The validating bridge contract is tasked with protecting the integrity of the widely replicated database and liveness such that a proposed state update will eventually be applied to the database. Figure 1 presents an overview of a validating bridge and it has two components:

– Off-chain system A system with its own appointment protocol, smart contract environment, and a widely replicated database that anyone can independently re-compute.

– Chain of commitments (commitchain) Periodic commitments about the off-chain system’s database state and the bridge must be convinced that all state updates to the database are valid before it can accept a new commitment.

An organization is still responsible for optimistically running the off-chain system. They must periodically propose a new cryptographic commitment that asserts the new state of the database and be prepared to defend their assertion by providing evidence for why it is valid. The bridge contract can leverage the potential evidence as a basis for a proof of fraud (discrepancy detection) or a validity proof (discrepancy prevention) before accepting the commitment. The validating bridge must be convinced the commit-chain is not compromised and every state update applied to the database is valid before it permits any funds to be withdrawn. As such, an off-chain system that is built with a validating bridge is considered a scaling solution as users can transact on an off-chain system with assets that reside on the underlying blockchain while retaining the underlying blockchain’s security.

In a cross-blockchain transaction, we assume that the transaction result can be a value transfer or the execution of a contract, and that:

• Underlying networks are secure with a concept of transaction finality within finite time, after which the transactions cannot be rolled back.

• We loosely use ‘value’ as the generic term to represent the cryptographic object that the blockchain carries.

• Security aspects such as double spending and 51% attack of cross-blockchain systems are addressed by the integration protocol.

• We do not consider the semantics of data and exchange rate between two different tokens.

For full understanding and the big picture of interoperability you can check this piece of work 👇👇👇

https://blog.infura.io/post/validating-bridges-scaling-blockchains

• Connext Network - Their team is well combined between entrepreneurs, Innovators & Technologists!!

🦾Founders - Arjun Bhaptani, Layne Haber & Rahul Sethuram

The team have experience with technological companies both Startups & big corporations located in US (San Francisco). The project is developing around 5 year till this day and it’s growing by Usage and Adoption. You can check the whole team - Here.

👀Key Advisors - After conducting a Series A funding round with raised total of $12M in funding the protocol started with partnerships and new products.

The key advisors/investors are one of most famous people in the crypto industry:

🏛Institutions: 1kx, Consensys Mesh, Coinbase Ventures, Polychain Capital and many others.

😇Angel Investors: Andre Cronje, Ed Felten, Jack O’Holleran, Sandeep Nailwal, Stani Kulechov, Alex Gluchowski, Slingshot Finance and many others.

Many familiar “faces” connected with Arbitrum, AAVE, Polygon, SKALE, Fantom & Slingshot Finance.

• Nomad

🦾Founders : @LukeTchang - Off-chain architect, protocol engineer, @ErinHales1 - Bridge GUI and SDK, @_prestwich - CTO, @pranaymohan - CEO, @barbaraliau - COO and @YourBuddyConner - The Bridgemaster - Sorry if I missed someone :-)

Highly dedicated and colorful team with huge knowledge and enthusiasm!

🏛Institutions:

They raised approximately $22.4 million in seed funding. The round was led by Polychain Capital, with additional investors including 1kx, Ethereal Ventures, hack.vc, Circle Ventures, Amber, Robot Ventures, Hypersphere, Figment, Dialectic, Archetype, LedgerPrime, and a host of angels.

😇Angel Investors: Polkadot, Aurora, Gitcoin, Optimistm and many others below.

To understand how the each protocol works individually you can check their Documentation (Nomad) - Documentation (Connext Network). Won’t get into details about that. The interesting part is the collaboration between them.

There is an Update going on called Amarok and basically this is where both protocols are combining power!

The motivation behind this is several areas of current issues:

1. Gas Costs: The current flow relies on a two-phase prepare/fulfill process to complete transactions across chains, which cannot be easily batched.

2. Signing to Claim: Completing transactions requires users to sign a message to claim funds. This is what keeps Connext trust-minimized, but is a pain because it requires users to stay online until they sign.

3. Fund Lockup Risk: User transactions have a 1:1 relationship with a router. If that router goes offline or loses its connection to the chain mid-flow, the user’s funds can be stuck until the transaction expires (72 hours).

4. Speed: Because users are bound to a given router for their transaction, any delays that that specific router experiences are passed down to the user.

5. Liquidity Fragmentation: Liquidity provided by routers is path-dependent meaning that it is available between a given pair of chains. As the number of chains grows, it becomes harder for users to make large transactions.

1. Offchain Auction Dependencies: Most integrations in the space are contracts-only, but Connext currently requires running a client-side sdk to find a router for a given transaction.

2. Signing to Claim: The need to claim requires devs to track in-progress transactions and prompt users to sign at the right time. This adds a lot of overhead and complexity compared to a simple onchain transaction.

3. No Generalized Messaging: Connext already supports calling contracts across chains, but this can only be done safely in some cases. Requiring devs to learn when they can and can’t use this feature is a big hurdle.

1. Rebalancing: Routers send funds on the destination chain and receive funds on the origin. This means their liquidity moves around between chains/rollups and can get stuck, lowering capital efficiency.

2. Unclear ROI: Router ROI is notoriously difficult to track accurately because the two-phase flow means that the data needed to track returns is fragmented across chains.

3. Strict Liveness: As mentioned above, if routers become unavailable during a transaction, user funds can be locked for up to 72 hours. This strict liveness requirement increases the difficulty of being a router.

4. Gas Griefing: Transactions can be cancelled collaboratively by users or routers. However, when this happens, there’s no clear mechanism to reimburse the upfront cost of gas.

With Amarok modular interoperability is introduced!

The breakthrough in our thinking comes from our close partnership with Nomad. Nomad is an optimistic bridge that gives us fully expressive, trust-minimized communication on any chain, but with the tradeoff of 30 minutes of latency.

We realized that, similar to blockchains themselves, there is no monolithic architecture that gives us all of the desireable properties that we need out of bridges, but we can get close to the ideal outcome by modularizing the protocol stack.

The modular interoperability stack

The new flow heavily utilizes Nomad (and eventually other localized messaging layers!) for its security model. Rather than requiring signatures, the approach simply allows any router to front capital and execute calls for a user’s transaction, and claim against funds going through Nomad.

Because no router is explicitly specified upfront, a risk exists that routers can race each other in the mempool to complete a given transaction. This is a suboptimal outcome as losing this race still costs gas for routers. To fix this, we introduce a Sequencer (similar in concept to a rollup sequencer) that is responsible for collecting bids (attempted transactions) from routers and publishing them to chain in batches.

Note that the sequencer role in Connext does not affect the core security of the system or its funds in any way . It is instead simply a mechanism designed to fairly distribute fee revenue/work among routers, which can be done trustlessly if there is (a) data availability of all router bids for a given user transaction, and (b) a deterministic process for selecting the winning bid. We are currently researching approaches to this, including potentially having the sequencer post data to its own rollup OR having routers and the sequencer achieve Tendermint consensus.

• One-click bridging: Faster, cheaper, and more seamless transfers across chains. Users will always receive native assets (or the most liquid and secure synthetic assets) at their destination.

• Building xchain applications: Developers are no longer limited to users, funds, or data on only a single chain. You can now build truly chain-agnostic experiences without sacrificing security. Think xchain swaps — any asset to any asset, xchain governance, xchain NFTs, and much more.

Both protocols probably will be huge part of the infrastructure for the whole crypto industry! Their approach is innovative and it’s resolving massive issues standing in front of the crypto space. With all of those proper advisors, investors the help and direction of the protocols won’t be missing!

Another important thing is that they are focused on Modular infrastructure which it seems is more agile and flexible for the future. The security is also taken very seriously!

There is no place for tribalism in the industry and the more frictionless, smooth the transition between chains more adoption there will be.

There is strong partnership with SuperFluid in the recent days, related with collaboration and technical integration that is set to create a new primitive in the blockchain ecosystem: fluid streaming of tokens across any domain and L2.

For more information: HERE

Follow them on Twitter, Use the projects and help if you have the time through their contributor program.

🧵🧶This is summarization of few bridging protocols engineering the bright future of cross-chain messaging and interoperability - Connext Network & Nomad.

The boom of bridging protocols/project appeared in 2021, however many of the bridges were running at huge risk of funds being lost during the chain transfer. The first thing I want to point out is that still the risk remains and many funds were lost!!!

The basic explanation is below:

V. Buterin puts it aptly in his tweet:

“Now, imagine what happens if you move 100 ETH onto a bridge on Solana to get 100 Solana-WETH, and then Ethereum gets 51% attacked. The attacker deposited a bunch of their own ETH into Solana-WETH and then reverted that transaction on the Ethereum side as soon as the Solana side confirmed it. The Solana-WETH contract is now no longer fully backed, and perhaps your 100 Solana-WETH is now only worth 60 ETH. Even if there’s a perfect ZK-SNARK-based bridge that fully validates consensus, it’s still vulnerable to theft through 51% attacks like this.”

After pointing out the danger of the bridges, we need to be able to improve and create safer projects around the area because the future it seems to be cross-chain and the opportunities hidden between them!

The validating bridge contract is tasked with protecting the integrity of the widely replicated database and liveness such that a proposed state update will eventually be applied to the database. Figure 1 presents an overview of a validating bridge and it has two components:

– Off-chain system A system with its own appointment protocol, smart contract environment, and a widely replicated database that anyone can independently re-compute.

– Chain of commitments (commitchain) Periodic commitments about the off-chain system’s database state and the bridge must be convinced that all state updates to the database are valid before it can accept a new commitment.

An organization is still responsible for optimistically running the off-chain system. They must periodically propose a new cryptographic commitment that asserts the new state of the database and be prepared to defend their assertion by providing evidence for why it is valid. The bridge contract can leverage the potential evidence as a basis for a proof of fraud (discrepancy detection) or a validity proof (discrepancy prevention) before accepting the commitment. The validating bridge must be convinced the commit-chain is not compromised and every state update applied to the database is valid before it permits any funds to be withdrawn. As such, an off-chain system that is built with a validating bridge is considered a scaling solution as users can transact on an off-chain system with assets that reside on the underlying blockchain while retaining the underlying blockchain’s security.

In a cross-blockchain transaction, we assume that the transaction result can be a value transfer or the execution of a contract, and that:

• Underlying networks are secure with a concept of transaction finality within finite time, after which the transactions cannot be rolled back.

• We loosely use ‘value’ as the generic term to represent the cryptographic object that the blockchain carries.

• Security aspects such as double spending and 51% attack of cross-blockchain systems are addressed by the integration protocol.

• We do not consider the semantics of data and exchange rate between two different tokens.

For full understanding and the big picture of interoperability you can check this piece of work 👇👇👇

https://blog.infura.io/post/validating-bridges-scaling-blockchains

• Connext Network - Their team is well combined between entrepreneurs, Innovators & Technologists!!

🦾Founders - Arjun Bhaptani, Layne Haber & Rahul Sethuram

The team have experience with technological companies both Startups & big corporations located in US (San Francisco). The project is developing around 5 year till this day and it’s growing by Usage and Adoption. You can check the whole team - Here.

👀Key Advisors - After conducting a Series A funding round with raised total of $12M in funding the protocol started with partnerships and new products.

The key advisors/investors are one of most famous people in the crypto industry:

🏛Institutions: 1kx, Consensys Mesh, Coinbase Ventures, Polychain Capital and many others.

😇Angel Investors: Andre Cronje, Ed Felten, Jack O’Holleran, Sandeep Nailwal, Stani Kulechov, Alex Gluchowski, Slingshot Finance and many others.

Many familiar “faces” connected with Arbitrum, AAVE, Polygon, SKALE, Fantom & Slingshot Finance.

• Nomad

🦾Founders : @LukeTchang - Off-chain architect, protocol engineer, @ErinHales1 - Bridge GUI and SDK, @_prestwich - CTO, @pranaymohan - CEO, @barbaraliau - COO and @YourBuddyConner - The Bridgemaster - Sorry if I missed someone :-)

Highly dedicated and colorful team with huge knowledge and enthusiasm!

🏛Institutions:

They raised approximately $22.4 million in seed funding. The round was led by Polychain Capital, with additional investors including 1kx, Ethereal Ventures, hack.vc, Circle Ventures, Amber, Robot Ventures, Hypersphere, Figment, Dialectic, Archetype, LedgerPrime, and a host of angels.

😇Angel Investors: Polkadot, Aurora, Gitcoin, Optimistm and many others below.

To understand how the each protocol works individually you can check their Documentation (Nomad) - Documentation (Connext Network). Won’t get into details about that. The interesting part is the collaboration between them.

There is an Update going on called Amarok and basically this is where both protocols are combining power!

The motivation behind this is several areas of current issues:

1. Gas Costs: The current flow relies on a two-phase prepare/fulfill process to complete transactions across chains, which cannot be easily batched.

2. Signing to Claim: Completing transactions requires users to sign a message to claim funds. This is what keeps Connext trust-minimized, but is a pain because it requires users to stay online until they sign.

3. Fund Lockup Risk: User transactions have a 1:1 relationship with a router. If that router goes offline or loses its connection to the chain mid-flow, the user’s funds can be stuck until the transaction expires (72 hours).

4. Speed: Because users are bound to a given router for their transaction, any delays that that specific router experiences are passed down to the user.

5. Liquidity Fragmentation: Liquidity provided by routers is path-dependent meaning that it is available between a given pair of chains. As the number of chains grows, it becomes harder for users to make large transactions.

1. Offchain Auction Dependencies: Most integrations in the space are contracts-only, but Connext currently requires running a client-side sdk to find a router for a given transaction.

2. Signing to Claim: The need to claim requires devs to track in-progress transactions and prompt users to sign at the right time. This adds a lot of overhead and complexity compared to a simple onchain transaction.

3. No Generalized Messaging: Connext already supports calling contracts across chains, but this can only be done safely in some cases. Requiring devs to learn when they can and can’t use this feature is a big hurdle.

1. Rebalancing: Routers send funds on the destination chain and receive funds on the origin. This means their liquidity moves around between chains/rollups and can get stuck, lowering capital efficiency.

2. Unclear ROI: Router ROI is notoriously difficult to track accurately because the two-phase flow means that the data needed to track returns is fragmented across chains.

3. Strict Liveness: As mentioned above, if routers become unavailable during a transaction, user funds can be locked for up to 72 hours. This strict liveness requirement increases the difficulty of being a router.

4. Gas Griefing: Transactions can be cancelled collaboratively by users or routers. However, when this happens, there’s no clear mechanism to reimburse the upfront cost of gas.

With Amarok modular interoperability is introduced!

The breakthrough in our thinking comes from our close partnership with Nomad. Nomad is an optimistic bridge that gives us fully expressive, trust-minimized communication on any chain, but with the tradeoff of 30 minutes of latency.

We realized that, similar to blockchains themselves, there is no monolithic architecture that gives us all of the desireable properties that we need out of bridges, but we can get close to the ideal outcome by modularizing the protocol stack.

The modular interoperability stack

The new flow heavily utilizes Nomad (and eventually other localized messaging layers!) for its security model. Rather than requiring signatures, the approach simply allows any router to front capital and execute calls for a user’s transaction, and claim against funds going through Nomad.

Because no router is explicitly specified upfront, a risk exists that routers can race each other in the mempool to complete a given transaction. This is a suboptimal outcome as losing this race still costs gas for routers. To fix this, we introduce a Sequencer (similar in concept to a rollup sequencer) that is responsible for collecting bids (attempted transactions) from routers and publishing them to chain in batches.

Note that the sequencer role in Connext does not affect the core security of the system or its funds in any way . It is instead simply a mechanism designed to fairly distribute fee revenue/work among routers, which can be done trustlessly if there is (a) data availability of all router bids for a given user transaction, and (b) a deterministic process for selecting the winning bid. We are currently researching approaches to this, including potentially having the sequencer post data to its own rollup OR having routers and the sequencer achieve Tendermint consensus.

• One-click bridging: Faster, cheaper, and more seamless transfers across chains. Users will always receive native assets (or the most liquid and secure synthetic assets) at their destination.

• Building xchain applications: Developers are no longer limited to users, funds, or data on only a single chain. You can now build truly chain-agnostic experiences without sacrificing security. Think xchain swaps — any asset to any asset, xchain governance, xchain NFTs, and much more.

Both protocols probably will be huge part of the infrastructure for the whole crypto industry! Their approach is innovative and it’s resolving massive issues standing in front of the crypto space. With all of those proper advisors, investors the help and direction of the protocols won’t be missing!

Another important thing is that they are focused on Modular infrastructure which it seems is more agile and flexible for the future. The security is also taken very seriously!

There is no place for tribalism in the industry and the more frictionless, smooth the transition between chains more adoption there will be.

There is strong partnership with SuperFluid in the recent days, related with collaboration and technical integration that is set to create a new primitive in the blockchain ecosystem: fluid streaming of tokens across any domain and L2.

For more information: HERE

Follow them on Twitter, Use the projects and help if you have the time through their contributor program.