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Homomorphic commitment

As explained in Real-World Cryptography

A homomorphic commitment is a cryptographic commitment that supports operations on committed values while preserving corresponding algebraic relationships.

A homomorphic commitment hides a value while allowing a verifier to perform selected operations on the hidden value. In zk-SNARKs, it helps check polynomial relationships without revealing the polynomial itself. section 15.3.1 section 15.3.2

Typical commitment checks include:

Polynomial divisibility check

A prover commits to f(x) and h(x), while the verifier computes a commitment to the agreed constraint t(x). The verifier checks com(f(x)) = com(t(x))com(h(x)), corresponding to f(x) = t(x)h(x), without receiving the polynomials openly. section 15.3.2

How Real-World Cryptography covers it

How deep it goes
Defines equality, addition, and public scaling, then adds pairings for one multiplication without detailing implementation.
Examples
Uses exponent commitments, polynomial divisibility, equality, addition, scaling, and pairing equations as concrete demonstrations.
What it assumes
Assumes basic commitment schemes and polynomial relationships while introducing homomorphic operations through simple equations.
What you can do after
Evaluate how commitments support hidden algebraic checks and recognize when multiplication needs bilinear pairings.
How it connects
Connects commitment schemes, zk-SNARKs, bilinear pairings, polynomial identities, hash functions, homomorphic encryption, and BLS signatures.

Related concepts

This explainer was generated by Manning's knowledge graph from the text of Real-World Cryptography. The section links point to the parts of the book it draws on.