In our online activities, we often give away more data than necessary, compromising our privacy without gaining any real benefits. However, zero knowledge cryptography, or ZK, offers a potential solution. By proving knowledge without revealing it, ZK enhances privacy, security, and efficiency. It allows users to selectively disclose relevant information, enables secure partnerships, ensures compliance with regulations, and revolutionizes how we interact in the digital world.

Aleo's mission is to empower developers to build truly private applications, and the cornerstone of our approach is zero knowledge cryptography. This technique allows parties on a decentralized network to prove knowledge without exposing the underlying facts.

Imagine a bartender verifying a person's age. Typically, they would ask for an ID, which contains more personal information than necessary. Zero knowledge cryptography allows the person to prove they are of legal drinking age without revealing any additional details. The bartender can verify this claim without even learning the person's age. This technology empowers individuals to share only relevant information while maintaining privacy.

Zero knowledge cryptography unlocks new business models and applications. These models leverage the capabilities provided by this technology. In this article, we explore the building blocks, or primitives, that zero knowledge cryptography uniquely enables.

Primitives are the basic building blocks or ingredients of a programming language. In the context of emerging technologies, they represent core components that can be combined and iterated to create novel solutions. Just like bonding curves are a primitive for decentralized finance on Ethereum, Aleo's zero knowledge primitives are essential for the development of private applications in the Web3 privacy space.

Privacy and programmability have been challenging to reconcile on blockchains. Existing solutions either prioritize one over the other or offer an unbalanced ratio. Aleo's zero knowledge primitives provide a set of core expectations that users and developers can rely on for every private, programmable application.

So, what are the primitives of zero knowledge applications?

Shielded Identities: These act as firewalls protecting private information. Similar to a cryptographically-based driver's license, shielded identities hide irrelevant details while allowing interactions between individuals, smart contracts, DAOs, and enterprises. For example, an on-chain know-your-customer (KYC) process can be conducted without revealing the entire account and asset holdings of a user, preserving anonymity.

Shielded Transactions: First pioneered by Zcash, shielded transactions in Aleo go beyond simple asset transfers. They encompass various interactions, such as liquidity provisioning, voting in governance, identity authentication, decentralized notifications, and more. Only the involved parties possess the transaction details, preventing malicious third parties from exploiting the information.

These shielded identities and transactions operate off-chain in Aleo's zkCloud environment. zkCloud facilitates peer-to-peer, decentralized, private computing, enabling secure interactions between shielded identities. By moving interactions off-chain, privacy is ensured, and transaction throughput is increased. Shielded transactions link the interactions within zkCloud to the Aleo blockchain, storing cryptographic proofs of their validity without disclosing program details or participants' identities. This approach guarantees privacy, scalability, and a decentralized data availability guarantee.

zkCloud applications can be executed locally or delegated to third-party proving services, allowing for a wider range of applications and a new marketplace for delegated private computation.

In summary:

zkCloud forms the basis for peer-to-peer, decentralized, private computation, executed locally or delegated to provers.
It enables programmatic interactions between shielded identities.
Shielded transactions provide cryptographic proofs for correct program execution.
These transactions are stored on the Aleo blockchain, anchoring zkCloud activity and ensuring decentralized and censorship-resistant data availability.
Aleo's core technology stack empowers developers to build truly private applications. By combining these zero knowledge primitives, developers can create decentralized applications that are private, scalable, and programmable. The vision of a fully private and decentralized Web3 ecosystem becomes achievable. In the next article of our series, we'll explore the possibilities unlocked by these building blocks. Stay tuned!