zkVM
A zkVM (Zero-Knowledge Virtual Machine) is a system that allows developers to prove that a program has executed correctly without revealing any details about the actual computation. Imagine it like this: you write a program in Rust (or another LLVM-compatible language) that performs a calculation, such as finding the 10th Fibonacci number.
Here’s how it works:
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Write and Compile the Program: Developers write a program in a language like Rust (or any other LLVM-compatible language). The program is compiled into an executable format, such as an ELF file (Executable and Linkable Format).
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Key Setup (Optional in Some Systems): Traditional zkVMs often require a key setup phase, one for proving and another for verifying.
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Generate a Proof: The zkVM runs the program with input data, generating a proof that the computation was done correctly.
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Verify the Proof: Anyone can then use the verification key to check the proof, confirming that the program’s output is correct without seeing the actual input or intermediate steps.
This process ensures privacy and trustworthiness in various applications, making it possible to verify complex computations securely.
Keyless zkVM Systems:
Some modern zkVM systems, such as those based on universal SNARKs (e.g., Halo2, PLONK), STARKs, or other advancements, eliminate the key setup step. These systems are often referred to as transparent zkVMs because they don’t rely on a trusted setup phase.
In such systems:
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No Trusted Setup: Cryptographic security is achieved without pre-generated keys, reducing trust assumptions and enhancing security.
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Flexible Proofs: These systems support generating proofs for any computation without requiring a new setup phase for each program.
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Examples of Transparent zkVMs: - zk-STARK-based zkVMs: Use hash-based commitments, offering scalability and removing the need for trusted setups. - PLONK-based zkVMs: Use a universal setup that works for multiple computations, making the system more versatile.