Succinct SP1: The Latest Tooling for Zero-Knowledge Proofs

Transparency is one of blockchain's core values; however, it comes at the expense of user privacy, as user transactions are visible to everyone, and scalability, as data is fully committed to the blockchain. Zero-knowledge proofs (ZKPs) have gained popularity as a method for improving scalability and achieving privacy on blockchain networks. Succinct Processor 1 (SP1) is a new tool in the ZKP domain that has the potential for mainstreaming this sophisticated technology, and this article will explain why.

What Are Zero-Knowledge Proofs?

Zero-knowledge proofs (ZKPs) are a novel approach to improving information security in digital environments, representing a significant advancement in applied cryptography.

The concept of zero-knowledge proofs was first introduced in the seminal 1985 paper "The knowledge complexity of interactive proof systems," which still serves as the foundational definition for ZKPs today.

Consider a situation in which you must verify your identity to a service provider. While you would normally have to present concrete evidence to support your claims, such as a passport or driver's license, this method may jeopardize the security of your personal information. The requirement to share Personally Identifiable Information (PII) with third parties leads to the accumulation of sensitive data in centralized repositories that are vulnerable to hacking and data breaches.

ZKPs enable an individual (the prover) to demonstrate the validity of a claim to another party (the verifier) while disclosing no information other than the claim's veracity. This method ensures that no additional information is conveyed other than the validity of the specific assertion being made.

How Do Zero-Knowledge Proofs Function?

A zero-knowledge proof consists of three key components: the witness, the challenge, and the response. The algorithm functions as follows: 

• Initially, the prover seeks to demonstrate possession of confidential information (the witness) by establishing a set of questions with information that only someone with such knowledge could answer and answering a random question from the list, thereby initiating the proof process.
• Following that, the verifier presents a randomly selected question (the challenge) for the prover to answer. 
• The prover then answers the question and relays the answer (the response) to the verifier, who, through this iterative process of questioning and answering, comes to believe in the prover's knowledge without ever learning the confidential information. This method effectively reduces the likelihood of the prover passing the test without having the secret knowledge.

What Are the Most Popular Use Cases of ZKPs?

Zero-knowledge proofs enable a wide range of Web3 use cases, including anonymous blockchain transactions, user authentication, and verifiable computations. Here are some examples:

1. Private transactions: ZKPs enable privacy on blockchains like Zcash, keeping transaction amounts and participant addresses private.
2. Verifiable computations: Utilised in decentralized oracle networks for verifying facts about off-chain data without disclosing the data itself.
3. Highly scalable and secure layer 2s: Through zk-Rollups, Validiums, and Volitions, ZKPs facilitate secure transactions and scalability on layer 2 solutions.
4. Decentralized identity and authentication: Supports identity verification systems where users can prove personal attributes (e.g., nationality) without revealing sensitive information (e.g., passport details).

So, why is ZKP not mainstream? For a long time, ZKP adoption has been difficult due to the need for specialized knowledge in ZKP frameworks and the difficult maintenance of one-time deployments. However, new tools that have the potential to accelerate the widespread adoption of this approach emerge. One of them is a zero-knowledge virtual machine (zkVM) SP1, a special type of virtual machine capable of running arbitrary code and producing proof of execution.

Succinct Processor 1 (SP1)

SP1 is a novel general-purpose zkVM, tailored for generating proofs for execution of code written in Rust and other languages compiled through LLVM. This innovation permits the use of maintainable Rust code with access to a standard library, moving beyond the need for specialized proving stacks. 

It employs a novel "shared challenges" technique, enabling the segmentation of extensive computations into manageable shards, which are then seamlessly interconnected to form a comprehensive global proof.

SP1 commits to openness and collaboration, fully embracing the open-source ethos under the MIT license with no code obfuscation. It builds on the foundation laid by other open-source projects, such as Plonky3 from Polygon Zero Labs (formerly The Mir Protocol), with the goal of creating the best zkVM for a variety of applications, including rollups and coprocessors.

Unlike other zkVMs that rely on closed-source constraint logic, SP1 is designed from the ground up to be modular, allowing for customization. 

Enhanced Performance

SP1 delivers cutting-edge performance and customizability when handling common real-world blockchain applications such as bridging. Its cross-table lookup architecture improves performance without incurring significant recursion costs.

SP1 zkVM includes built-in precompiles that speed up specific operations like hashing (e.g., SHA256, Keccak256) and elliptic curve arithmetic (e.g., Ed25519, Secp256k1) by orders of magnitude. Precompiles are exposed within the zkVM as system calls that are executed using the ecall RISC-V instruction. SP1 has also been designed to make it simple for external contributors to build and extend the zkVM using their own precompiles, resulting in significant performance gains. SP1 outperforms both existing zkVMs and is on par with, if not better than, circuit-based approaches in a wide range of use cases.

Even in the Alpha stage, Succinct benchmarks show that SP1 outperforms the RISC Zero zkVM by 4 to 28 times for specific tasks, demonstrating its competitive edge. 

From a development standpoint, Succinct emphasizes a significant reduction in time and effort for developers, estimating a more than 100-fold decrease in development time when using SP1 over custom circuit approaches. This efficiency gain is largely due to the ability to use maintainable Rust code, which eliminates the need to develop one-off custom solutions and streamlines the development process.

Looking Ahead

With advances in the field of zero-knowledge proofs, general-purpose zero-knowledge virtual machines such as SP1 have the potential to transform the blockchain landscape.

The introduction of performant, general-purpose zkVMs is expected to render custom ZK stacks obsolete, paving the way for a new paradigm in blockchain infrastructure. This future vision includes rollups, bridges, coprocessors, and more, all of which use ZKPs via easily maintainable software written in Rust or other LLVM-compiled languages.

Currently, SP1 performs exceptionally well on practical blockchain workloads. This is a significant step toward the widespread adoption of ZKPs, a powerful technology that promises to improve scalability and security in the blockchain ecosystem.

Conclusion

As we approach this blockchain shift, the promise of general-purpose zkVM solutions like SP1 heralds a future in which the complexity and exclusivity of custom ZK stacks are replaced by a more accessible and unified approach in blockchain development.