Echo FAQ

General FAQ

What is Echo?

Echo is a Layer 2 overlay network that integrates with existing blockchains to provide interoperability and new advanced scripting features for crypto assets. Similar to how the internet is built in different communication layers and protocols, Echo creates an entirely new layer of communication enabling high-speed asset transfers and new types of decentralized applications or "smart contracts" to interact with existing cryptocurrencies like bitcoin and ether.

What is Layer 2?

Layer 2 is used to describe projects and protocols that build on the foundation of existing blockchains to provide new functionality. Some examples include the Lightning Network for Bitcoin and Plasma for Ethereum.

How is Echo different from other Layer 2 solutions?

While many popular Layer 2 solutions like the Lightning Network focus on off-chain transactions or transfers using the same asset, Echo's goal is to connect many different blockchains and enable new functionality with the underlying blockchain assets.

What blockchains does Echo work with?

Currently, Echo interoperates with Bitcoin, Ethereum and Ethereum assets such as ERC-20 tokens. In the future, Echo will connect to and support new, unique foundational blockchains.

Is Echo decentralized?

Similar to existing blockchain protocols, the Echo network is open for anyone globally to join, permissionlessly and voluntarily, by running the open-source Echo node software. Anyone can become an Echo validator or block producer. While the number of validating nodes is low on the current testnet, the decentralization will increase as more people use Echo.

How can I use Echo?

You can download the Echo desktop wallet or Echo mobile wallet today to begin sending and receiving assets, deploying and interacting with decentralized applications, and participating in network validation.

What is the status of Echo?

Today, the Echo network is running on a stable test network ("testnet") that has been active for 6 months. Echo has been under active development for 18 months to create the desktop wallet, mobile wallet, node software, browser extension, developer libraries and block explorers necessary to interact with the network.

When will Echo be live?

Echo is currently live on an open, public test network. The Echo main network will launch in Q2 2019.

Does Echo have a token?

Echo supports a wide range of assets and tokens, including native assets, sidechain assets and contract-controlled tokens. Echo has a core asset, the ECHO token, which is used for the security mechanism of the consensus algorithm. ECHO tokens are also used as a type of “gas” fee currency, to protect the network against spam or DDoS attacks. The ECHO token is inflationary and used to reward full nodes for participating in EchoRand consensus.

Do I need ECHO tokens to use the Echo network?

No, you can download the Echo wallet and begin sending and receiving other assets without requiring any ECHO. Transaction fees can be paid in many different currencies and are converted into ECHO by the protocol’s underlying fee pools. Additionally, decentralized applications in Echo can pay for their own execution so that users aren’t required to individually pay transaction fees.

How can I get some ECHO tokens?

Testnet ECHO is available from a faucet and distributed to all testnet users freely.

EchoRand Consensus

What is Echo's consensus mechanism?

Echo uses an open, permissionless, proof-of-stake-based algorithm called EchoRand. There is no computationally intensive proof-of-work process; instead, EchoRand uses a verifiable random function (VRF) to randomly select a pool of block producers and block verifiers based on their stake to add each new block of transactions to the Echo blockchain.

What is a VRF?

A verifiable random function (VRF) is a pseudo-random cryptographic function that is used in EchoRand to choose the block producers and block verifiers for each block through cryptographic sortition. This function allows each participating node to independently compute if it is chosen for a verification role for the next block and to broadcast that proof along with the block. This prevents any node in Echo from knowing who will produce the next block ahead of time, mitigating some classes of bribe or targeted DDoS attacks.

How is EchoRand different from DPoS blockchains?

Unlike traditional delegated-proof-of-stake (DPoS) blockchains, there is no superset of elected or delegated "supernodes" that produce and validate each block. Instead, every node in the network participates in block production and verification when chosen randomly according to its account balance.

How is EchoRand different from Algorand?

EchoRand uses similar cryptographic sortition and VRF functions to Algorand, but uses a different set of consensus steps for block verifiers and a new incentive model. Specifically, Echo changes the way it determines the participation of a specific account in a given role, and the method for generating a shared random state, in the third step of the Binary Byzantine Agreement algorithm. Echo also implements a delegation mechanism and an incentive model to reward participation in consensus by network users.
EchoRand builds on the proof-of-stake consensus research begun by many independent blockchain projects including Graphene, BitShares, Algorand, Steemit, Dfinity and EOS.

How does Echo address the "nothing at stake" problem?

Because EchoRand selects only a small subset of nodes to verify each block, those nodes must reach Byzantine agreement about the validity of the block. That means that it is not possible for nodes to "stake" for different competing blocks simultaneously, mitigating the "nothing at stake" scenario. If the block verifiers don't reach Byzantine agreement or general consensus about which block to add, no block is appended to the chain.

What is the security model?

Like many Byzantine Fault Tolerance (BFT) consensus algorithms, Echo requires an honest majority of 2/3 + 1 to reach consensus and confirm a given block. If that consensus is not met, an empty block is added to the chain and a new set of block producers and verifiers is chosen for the next block. In contrast to an attacker needing 51% of hash power to disrupt or cause a reorganization in proof-of-work blockchains, an attacker would need to acquire 67% of the total ECHO balance.

What is the block confirmation time?

Average block time on the current Echo testnet is 3.1 seconds.

Virtual Machine

What virtual machines does Echo support?

Echo has a dual virtual machine that integrates both the Ethereum virtual machine and a traditional x86-64 virtual machine.

How is Echo compatible with Ethereum contracts?

Because Echo supports the EVM, it means that Solidity contracts (and even compiled Solidity bytecode) can be deployed and executed seamlessly on Echo. This also means that existing smart contract development tools, libraries and analyzers can be used for Echo, such as Truffle, OpenZeppelin and MythX.

How do I deploy a Solidity contract to Echo?

What is the x64 virtual machine?

Echo's x64 virtual machine emulates the architecture of current CPUs, allowing the execution of bytecode created by standard compilers like GCC.

Why does Echo implement an x64 virtual machine?

The x64 virtual machine enables the Echo blockchain to run decentralized applications or smart contracts written in many traditional programming languages, in addition to Solidity. This means that developers can also leverage the decades of open-source development invested into compilers, linkers, IDEs and debugging tools that they are already familiar with.

What programming languages is Echo compatible with?

Ada, C, C++, D, Eiffel, Go, Haskell, Pascal, Python, Rust, Solidity and more.

How do you deploy a C++ smart contract to Echo?

Sidechains

What is a sidechain?

A sidechain is a method of representing an asset (such as bitcoin) from its native blockchain onto a new blockchain infrastructure. A sidechain is typically created through a two-way peg, where some assets are locked on the original chain before the corresponding assets are created on the destination chain. Examples of other sidechains include Liquid and RSK for Bitcoin and POA Network for Ethereum.

How do Echo sidechains work?

Similar to other production sidechains, Echo's sidechains work through a two-way peg to the native blockchain. For Bitcoin, this means that BTC is deposited into a multisig address, and a corresponding amount of Echo BTC, or eBTC, is minted on the Echo blockchain to the user who initiated the deposit. The new eBTC can be used to interact with a smart contract, traded on a decentralized exchange or transferred to another user. When the eBTC needs to be converted back to BTC, it can be locked into a contract, and the corresponding amount of BTC will be released on the Bitcoin chain. The protocol ensures that the same BTC cannot be valid on both blockchains at the same time.

Is Echo compatible with Bitcoin?

Yes, Echo supports BTC through a federated, pegged sidechain.

Is Echo compatible with Ethereum?

Yes, Echo currently supports ETH and its corresponding Echo asset, eETH.

Is Echo compatible with ERC-20 tokens?

Yes. Echo supports all ERC-20 standard Ethereum assets and allows them to be moved on and off Echo through the Ethereum sidechain.

Who secures the funds in a sidechain?

For BTC, Echo uses a federated model similar to Liquid and RSK to secure the multisig keys for Bitcoin. The federated key holders are called "witnesses" in Echo. The Echo team is actively pursuing new research into more decentralized security models and their applications in Bitcoin, such as drivechains and Typhon.

How can I be sure the sidechains are pegged?

At any time, you can independently verify that the amount of a sidechain asset like eBTC matches the amount of BTC secured on the Bitcoin chain.