Precise Proofs Example

example.go

// ExampleDocument is a protobuf message
document := documents.ExampleDocument{
  Value1: 1,
  ValueA: "Foo",
  ValueB: "Bar",
  ValueBytes1: []byte("foobar"),
}

// The FillSalts method is a helper function that fills all fields with 32 
// random bytes. SaltedExampleDocument is a protobuf message that has the 
// same structure as ExampleDocument but has all `bytes` field types.
salts := documents.SaltedExampleDocument{}
proofs.FillSalts(&salts)

doctree := proofs.NewDocumentTree()
sha256Hash := sha256.New()
doctree.SetHashFunc(sha256Hash)
doctree.FillTree(&document, &salts)
fmt.Printf("Generated tree: %s\n", doctree.String())
// Output:
// Generated tree: DocumentTree with Hash [k4E4F9xgvzDPtCGE0yM1QRguleSxQX6sZ14VTYAYVTk=] and [5] leaves

proof, _ := doctree.CreateProof("ValueA")
proofJson, _ := json.Marshal(proof)
fmt.Println(string(proofJson))
// Output:
// {"property":"ValueA","value":"Foo","salt":"YSJ0pFJ4fk0gYsCOU2zLC1xAcqSDcw7tdV4M5ydlCNw=","hashes":[{"right":"anfIr8Oa4PjWQsf2qFLIGgFBeBphTI+RGBaKp8F6Fw0="},{"left":"B+/DkYDB2vvYAuw9GTbVk7jpxM2vPddxsbhldM1wOus="},{"right":"hCkGp+gqakfRE1aLg4j4mA9eAvKn0LbulLOAKUVLSCg="}]}

valid, _ := doctree.ValidateProof(&proof)
fmt.Printf("Proof validated: %v\n", valid)
// Output:
// Proof validated: true