WIP wrapped hash

Consensys · Oct 25, 2023 · f58117b · f58117b
1 parent d1ab301
commit f58117b
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Showing 2 changed files with 17 additions and 27 deletions.
diff --git a/std/recursion/wrapped_hash.go b/std/recursion/wrapped_hash.go
@@ -111,13 +111,10 @@ func (h *shortNativeHash) Sum(b []byte) []byte {
 	h.ringBuf.Read(h.buf[1:])
 	h.wrapped.Write(h.buf)
 
-	// TODO: I'm cutting the hash on bit short to avoid edge cases:
+	// cut the hash a byte short to definitely fit
 	res := h.wrapped.Sum(nil)
-	fmt.Printf("sum %x\n", res)
-	nbBytes := (h.outSize + 7) / 8
-	res = res[len(res)-nbBytes+1:]
-	// mask := (1 << ((h.outSize - 1) % 8)) - 1
-	// res[0] &= byte(mask)
+	nbBytes := (h.outSize+7)/8 - 1
+	res = res[len(res)-nbBytes:]
 	return append(b, res...)
 }
 
@@ -136,23 +133,23 @@ func (h *shortNativeHash) BlockSize() int {
 }
 
 type shortCircuitHash struct {
-	api       frontend.API
-	bitLength int
-	wrapped   stdhash.FieldHasher
-	buf       []frontend.Variable
-	tmp       []frontend.Variable
+	api     frontend.API
+	outSize int
+	wrapped stdhash.FieldHasher
+	buf     []frontend.Variable
+	tmp     []frontend.Variable
 }
 
 func newHashFromParameter(api frontend.API, hf stdhash.FieldHasher, bitLength int) stdhash.FieldHasher {
-	tmp := make([]frontend.Variable, ((bitLength+7)/8)*8-8)
+	tmp := make([]frontend.Variable, ((api.Compiler().FieldBitLen()+7)/8)*8-8)
 	for i := range tmp {
 		tmp[i] = 0
 	}
 	return &shortCircuitHash{
-		api:       api,
-		bitLength: bitLength,
-		wrapped:   hf,
-		tmp:       tmp,
+		api:     api,
+		outSize: bitLength,
+		wrapped: hf,
+		tmp:     tmp,
 	}
 }
 
@@ -190,9 +187,8 @@ func (h *shortCircuitHash) Sum() frontend.Variable {
 	v := bits.FromBinary(h.api, h.tmp)
 	h.wrapped.Write(v)
 	res := h.wrapped.Sum()
-	h.api.Println(res)
 	resBts := bits.ToBinary(h.api, res)
-	res = bits.FromBinary(h.api, resBts[:len(h.tmp)])
+	res = bits.FromBinary(h.api, resBts[:((h.outSize+7)/8-1)*8])
 	return res
 }
 

diff --git a/std/recursion/wrapped_hash_test.go b/std/recursion/wrapped_hash_test.go
@@ -31,7 +31,6 @@ func (c *shortHashCircuit) Define(api frontend.API) error {
 
 func TestShortHash(t *testing.T) {
 	outerCurves := []ecc.ID{
-		// tinyfield.Modulus(),
 		ecc.BN254,
 		ecc.BLS12_381,
 		ecc.BLS12_377,
@@ -51,7 +50,7 @@ func TestShortHash(t *testing.T) {
 	}
 
 	assert := test.NewAssert(t)
-	nbInputs := 100
+	nbInputs := 19
 	for _, outer := range outerCurves {
 		outer := outer
 		for _, inner := range innerCurves {
@@ -63,21 +62,16 @@ func TestShortHash(t *testing.T) {
 				witness := &shortHashCircuit{Input: make([]frontend.Variable, nbInputs), inner: inner}
 				buf := make([]byte, (outer.ScalarField().BitLen()+7)/8)
 				for i := range witness.Input {
-					// el, _ := new(big.Int).SetString("1231231230981238971241240982112382934728934798234981324798123981724198712467928497124987124", 10)
-					// el.Mod(el, outer)
 					el, err := rand.Int(rand.Reader, outer.ScalarField())
 					assert.NoError(err)
 					el.FillBytes(buf)
-					// fmt.Printf("input: %x\n", buf)
 					h.Write(buf)
 					witness.Input[i] = el
 				}
 				res := h.Sum(nil)
 				witness.Output = res
-				err = test.IsSolved(circuit, witness, outer.ScalarField())
-				assert.NoError(err)
-				// assert.CheckCircuit(circuit, test.WithCurves(outer), test.WithValidAssignment(witness), test.NoFuzzing(), test.NoSerializationChecks(), test.NoSolidityChecks())
-			}, inner.String())
+				assert.CheckCircuit(circuit, test.WithCurves(outer), test.WithValidAssignment(witness), test.NoFuzzing(), test.NoSerializationChecks(), test.NoSolidityChecks())
+			}, outer.String(), inner.String())
 		}
 	}
 }