Zero-knowledge proofs (zk) are gaining popularity in the blockchain space as a solution to many different problems. The concept has been used in cryptography for quite some time, originating in the 1985 paper “Knowledge Complexity in Interactive Proof Systems.” Until recently, practical use cases were limited due to computational complexity.

Zcash has developed a digital currency and transaction protocol using zk proofs as a means of keeping transaction details private when two parties are conducting business. This solves one of the problems of using blockchain for transactions, where you might not want everyone on the planet to know who you paid and how much you paid them - just like most people wouldn't publicly share that kind of information with your bank account.

Layer 2 blockchains compatible with Ethereum Virtual Machines, such as Polygon, implement zk stores, which are essentially a large batch of transactions aggregated by the Layer 2 blockchain and presented to the Ethereum blockchain with zero-knowledge proof of their authenticity. This results in fewer Ethereum transactions, which in turn results in increased throughput and lower gas fees when interacting with the Ethereum blockchain.

Aleo, a layer 1 blockchain, takes these concepts further by creating an ecosystem for building decentralized applications for use cases where you might want to get some performance benefits from zk savings, coupled with the notion that certain aspects of blockchain transactions benefit from maintaining a level of confidentiality.

Why dApps need privacy

One of the often touted aspects of blockchain technology is the public nature of all transactions. There are examples of using, for example, zcash to maintain a certain level of banking privacy where completely open transaction data is not ideal. In an interview with The New Stack, Howard Wu, co-founder and CEO of Aleo, said: “There are a wide range of verticals where Web3 lacks privacy. This is not because we need to pin it down, but because many applications require some kind of information asymmetry or knowledge hiding in order to even function correctly”.

Wu gave one example of using blockchain to play poker. “The dealer might deal cards to seven or eight other players and ask everyone to check or bet,” he said. “Each player can create a zero-knowledge proof that follows every previous player and combine it into a single transaction, which is then passed down the chain, playing one round of the game and then moving on to the next round.” All of this happens without individual players knowing who has what cards in their hands..

Other real-world applications use a combination of open and closed states. Aleo gives developers the ability to make implementation decisions around information that is made public rather than proprietary. Voting is another practical use case that requires this flexibility. Wu said: “In elections, people want to vote, but they don't want to show other people how they voted. The counting of votes must be public in order to understand the result. Having private votes and public vote counting eventually becomes a feature in the apps used here”.

From the developer's implementation point of view, all elements that are designated as private are encrypted. A zero-knowledge proof is what is used to prove that a user is encrypting data using their public address, which means it can be verified that the person performing the action is who they say they are, but the public address is encrypted , so it cannot be viewed chained. A zero-knowledge proof is ultimately what proves that the encryption algorithm, decryption algorithm, and logic are executed "under the hood"".

Writing Aleo dApps using Leo

One of the unique aspects of Aleo's approach to DApp development is the accompanying Leo programming language. In my interview with Wu, I suggested that adding another programming language to the blockchain space could negatively impact its adoption. “When we started,” he replied, “we wanted to anchor it in Rust or Typescript so we wouldn't have to reinvent the wheel. It turns out that this is really hard to do, because what you might think is cheap in one programming model turns out to be very expensive in this model. We ended up creating a new language because what the compiler does is very different from the traditional architecture”.

How exactly is Leo different from Rust or Typescript? “We have a high-level language that compiles into polynomials that are executed inside the verification system,” he said. “The verification system works with polynomials to produce the final result. The end result looks the same as the output of a conventional processor, but it is accompanied by a zero-knowledge proof, which can indicate that the calculation was performed from a certain program on some hidden input data, which can also be made publicly available at the user's discretion. This is the main difference in architecture.”

“If you use LLVM for Rust or C++,” he continued, “you essentially need to abandon the LLVM architecture and invent a new architecture. The problem is that syntax that you would normally think of as cheap in a high level language ends up being very expensive”.

One of the ways Aleo is trying to overcome the challenges of adopting a new programming language is by making package management a core part of the Aleo ecosystem project. When developing for Ethereum, every time an ERC-20 token is deployed, the SafeMath contract is also deployed. Aleo allows you to reference packages instead of having to reuse them every time in your code. As Wu says, “The goal is to create an ecosystem of packages where you can start writing single code rather than reinventing features that have been written before.””.

Aleo also allows you to continue development using existing tools. Wu said: “Most users interacting with blockchains use existing SDKs from their respective dApps. From our perspective, we intend to add support for JavaScript, Wasm and Rust from day one to interact with Leo and Aleo programs to make it as easy as possible to access applications that have already been deployed using the traditional software stacks you are already familiar with”.

Aleo Official Sources

• Website ~ https://www.aleo.org/

• Twitter ~ https://twitter.com/AleoHQ

• Community Twitter ~ https://twitter.com/aleocommunity

• GitHub ~ https://github.com/AleoHQ

• Community Forum — https://community.aleo.org/

• Community Calendar ~ https://www.aleo.org/community/calendar

• YouTube — https://www.youtube.com/channel/UCS_HKT2heOC_q88YQLiJt0g

• Developer Documentation ~ https://developer.aleo.org/

• Leo Playground ~ https://play.leo-lang.org/

• Aleo Block Explorer ~ https://www.aleo.network/

Zero-knowledge proofs (zk) are gaining popularity in the blockchain space as a solution to many different problems. The concept has been used in cryptography for quite some time, originating in the 1985 paper “Knowledge Complexity in Interactive Proof Systems.” Until recently, practical use cases were limited due to computational complexity.

Zcash has developed a digital currency and transaction protocol using zk proofs as a means of keeping transaction details private when two parties are conducting business. This solves one of the problems of using blockchain for transactions, where you might not want everyone on the planet to know who you paid and how much you paid them - just like most people wouldn't publicly share that kind of information with your bank account.

Layer 2 blockchains compatible with Ethereum Virtual Machines, such as Polygon, implement zk stores, which are essentially a large batch of transactions aggregated by the Layer 2 blockchain and presented to the Ethereum blockchain with zero-knowledge proof of their authenticity. This results in fewer Ethereum transactions, which in turn results in increased throughput and lower gas fees when interacting with the Ethereum blockchain.

Aleo, a layer 1 blockchain, takes these concepts further by creating an ecosystem for building decentralized applications for use cases where you might want to get some performance benefits from zk savings, coupled with the notion that certain aspects of blockchain transactions benefit from maintaining a level of confidentiality.

Why dApps need privacy

One of the often touted aspects of blockchain technology is the public nature of all transactions. There are examples of using, for example, zcash to maintain a certain level of banking privacy where completely open transaction data is not ideal. In an interview with The New Stack, Howard Wu, co-founder and CEO of Aleo, said: “There are a wide range of verticals where Web3 lacks privacy. This is not because we need to pin it down, but because many applications require some kind of information asymmetry or knowledge hiding in order to even function correctly”.

Wu gave one example of using blockchain to play poker. “The dealer might deal cards to seven or eight other players and ask everyone to check or bet,” he said. “Each player can create a zero-knowledge proof that follows every previous player and combine it into a single transaction, which is then passed down the chain, playing one round of the game and then moving on to the next round.” All of this happens without individual players knowing who has what cards in their hands..

Other real-world applications use a combination of open and closed states. Aleo gives developers the ability to make implementation decisions around information that is made public rather than proprietary. Voting is another practical use case that requires this flexibility. Wu said: “In elections, people want to vote, but they don't want to show other people how they voted. The counting of votes must be public in order to understand the result. Having private votes and public vote counting eventually becomes a feature in the apps used here”.

From the developer's implementation point of view, all elements that are designated as private are encrypted. A zero-knowledge proof is what is used to prove that a user is encrypting data using their public address, which means it can be verified that the person performing the action is who they say they are, but the public address is encrypted , so it cannot be viewed chained. A zero-knowledge proof is ultimately what proves that the encryption algorithm, decryption algorithm, and logic are executed "under the hood"".

Writing Aleo dApps using Leo

One of the unique aspects of Aleo's approach to DApp development is the accompanying Leo programming language. In my interview with Wu, I suggested that adding another programming language to the blockchain space could negatively impact its adoption. “When we started,” he replied, “we wanted to anchor it in Rust or Typescript so we wouldn't have to reinvent the wheel. It turns out that this is really hard to do, because what you might think is cheap in one programming model turns out to be very expensive in this model. We ended up creating a new language because what the compiler does is very different from the traditional architecture”.

How exactly is Leo different from Rust or Typescript? “We have a high-level language that compiles into polynomials that are executed inside the verification system,” he said. “The verification system works with polynomials to produce the final result. The end result looks the same as the output of a conventional processor, but it is accompanied by a zero-knowledge proof, which can indicate that the calculation was performed from a certain program on some hidden input data, which can also be made publicly available at the user's discretion. This is the main difference in architecture.”

“If you use LLVM for Rust or C++,” he continued, “you essentially need to abandon the LLVM architecture and invent a new architecture. The problem is that syntax that you would normally think of as cheap in a high level language ends up being very expensive”.

One of the ways Aleo is trying to overcome the challenges of adopting a new programming language is by making package management a core part of the Aleo ecosystem project. When developing for Ethereum, every time an ERC-20 token is deployed, the SafeMath contract is also deployed. Aleo allows you to reference packages instead of having to reuse them every time in your code. As Wu says, “The goal is to create an ecosystem of packages where you can start writing single code rather than reinventing features that have been written before.””.

Aleo also allows you to continue development using existing tools. Wu said: “Most users interacting with blockchains use existing SDKs from their respective dApps. From our perspective, we intend to add support for JavaScript, Wasm and Rust from day one to interact with Leo and Aleo programs to make it as easy as possible to access applications that have already been deployed using the traditional software stacks you are already familiar with”.

Aleo Official Sources

• Website ~ https://www.aleo.org/

• Twitter ~ https://twitter.com/AleoHQ

• Community Twitter ~ https://twitter.com/aleocommunity

• GitHub ~ https://github.com/AleoHQ

• Community Forum — https://community.aleo.org/

• Community Calendar ~ https://www.aleo.org/community/calendar

• YouTube — https://www.youtube.com/channel/UCS_HKT2heOC_q88YQLiJt0g

• Developer Documentation ~ https://developer.aleo.org/

• Leo Playground ~ https://play.leo-lang.org/

• Aleo Block Explorer ~ https://www.aleo.network/