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Merged
merged 1 commit into from
Mar 4, 2022
Merged

Add functions to retrieve params of a Suite. #325

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20 changes: 10 additions & 10 deletions oprf/client.go
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Original file line number Diff line number Diff line change
Expand Up @@ -30,7 +30,7 @@ func (c client) Blind(inputs [][]byte) (*FinalizeData, *EvaluationRequest, error

blinds := make([]Blind, len(inputs))
for i := range inputs {
blinds[i] = c.params.Group.RandomScalar(rand.Reader)
blinds[i] = c.params.group.RandomScalar(rand.Reader)
}

return c.blind(inputs, blinds)
Expand All @@ -51,11 +51,11 @@ func (c client) blind(inputs [][]byte, blinds []Blind) (*FinalizeData, *Evaluati
blindedElements := make([]Blinded, len(inputs))
dst := c.params.getDST(hashToGroupDST)
for i := range inputs {
point := c.params.Group.HashToElement(inputs[i], dst)
point := c.params.group.HashToElement(inputs[i], dst)
if point.IsIdentity() {
return nil, nil, ErrInvalidInput
}
blindedElements[i] = c.params.Group.NewElement().Mul(point, blinds[i])
blindedElements[i] = c.params.group.NewElement().Mul(point, blinds[i])
}

evalReq := &EvaluationRequest{blindedElements}
Expand All @@ -66,8 +66,8 @@ func (c client) blind(inputs [][]byte, blinds []Blind) (*FinalizeData, *Evaluati

func (c client) unblind(serUnblindeds [][]byte, blindeds []group.Element, blind []Blind) error {
var err error
invBlind := c.params.Group.NewScalar()
U := c.params.Group.NewElement()
invBlind := c.params.group.NewScalar()
U := c.params.group.NewElement()

for i := range blindeds {
invBlind.Inv(blind[i])
Expand Down Expand Up @@ -96,7 +96,7 @@ func (c client) finalize(f *FinalizeData, e *Evaluation, info []byte) ([][]byte,
return nil, err
}

h := c.params.Hash.New()
h := c.params.hash.New()
outputs := make([][]byte, len(f.inputs))
for i := range f.inputs {
outputs[i] = c.params.finalizeHash(h, f.inputs[i], info, unblindedElements[i])
Expand All @@ -119,7 +119,7 @@ func (c VerifiableClient) Finalize(f *FinalizeData, e *Evaluation) (outputs [][]
}

if !(dleq.Verifier{Params: c.getDLEQParams()}).VerifyBatch(
c.params.Group.Generator(),
c.params.group.Generator(),
c.pkS.e,
f.evalReq.Elements,
e.Elements,
Expand All @@ -142,7 +142,7 @@ func (c PartialObliviousClient) Finalize(f *FinalizeData, e *Evaluation, info []
}

if !(dleq.Verifier{Params: c.getDLEQParams()}).VerifyBatch(
c.params.Group.Generator(),
c.params.group.Generator(),
tweakedKey,
e.Elements,
f.evalReq.Elements,
Expand All @@ -160,8 +160,8 @@ func (c PartialObliviousClient) pointFromInfo(info []byte) (group.Element, error
return nil, err
}

T := c.params.Group.NewElement().MulGen(m)
tweakedKey := c.params.Group.NewElement().Add(T, c.pkS.e)
T := c.params.group.NewElement().MulGen(m)
tweakedKey := c.params.group.NewElement().Add(T, c.pkS.e)
if tweakedKey.IsIdentity() {
return nil, ErrInvalidInfo
}
Expand Down
14 changes: 7 additions & 7 deletions oprf/keys.go
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Original file line number Diff line number Diff line change
Expand Up @@ -27,7 +27,7 @@ func (k *PrivateKey) UnmarshalBinary(s Suite, data []byte) error {
return ErrInvalidSuite
}
k.p = p
k.k = k.p.Group.NewScalar()
k.k = k.p.group.NewScalar()

return k.k.UnmarshalBinary(data)
}
Expand All @@ -38,14 +38,14 @@ func (k *PublicKey) UnmarshalBinary(s Suite, data []byte) error {
return ErrInvalidSuite
}
k.p = p
k.e = k.p.Group.NewElement()
k.e = k.p.group.NewElement()

return k.e.UnmarshalBinary(data)
}

func (k *PrivateKey) Public() *PublicKey {
if k.pub == nil {
k.pub = &PublicKey{k.p, k.p.Group.NewElement().MulGen(k.k)}
k.pub = &PublicKey{k.p, k.p.group.NewElement().MulGen(k.k)}
}

return k.pub
Expand All @@ -61,7 +61,7 @@ func GenerateKey(s Suite, rnd io.Reader) (*PrivateKey, error) {
if !ok {
return nil, ErrInvalidSuite
}
privateKey := p.Group.RandomScalar(rnd)
privateKey := p.group.RandomScalar(rnd)

return &PrivateKey{p, privateKey, nil}, nil
}
Expand All @@ -83,13 +83,13 @@ func DeriveKey(s Suite, mode Mode, seed, info []byte) (*PrivateKey, error) {
deriveInput := append(append(append([]byte{}, seed...), lenInfo...), info...)

dst := p.getDST(deriveKeyPairDST)
zero := p.Group.NewScalar()
privateKey := p.Group.NewScalar()
zero := p.group.NewScalar()
privateKey := p.group.NewScalar()
for counter := byte(0); privateKey.IsEqual(zero); counter++ {
if counter > maxTries {
return nil, ErrDeriveKeyPairError
}
privateKey = p.Group.HashToScalar(append(deriveInput, counter), dst)
privateKey = p.group.HashToScalar(append(deriveInput, counter), dst)
}

return &PrivateKey{p, privateKey, nil}, nil
Expand Down
38 changes: 23 additions & 15 deletions oprf/oprf.go
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Original file line number Diff line number Diff line change
Expand Up @@ -82,24 +82,29 @@ func isValidMode(m Mode) bool {
return m == BaseMode || m == VerifiableMode || m == PartialObliviousMode
}

type Suite interface{ cannotBeImplementedExternally() }
type Suite interface {
ID() int
Group() group.Group
Hash() crypto.Hash
cannotBeImplementedExternally()
}

var (
// SuiteP256 represents the OPRF with P-256 and SHA-256.
SuiteP256 Suite = params{ID: 3, Group: group.P256, Hash: crypto.SHA256}
SuiteP256 Suite = params{id: 3, group: group.P256, hash: crypto.SHA256}
// SuiteP384 represents the OPRF with P-384 and SHA-384.
SuiteP384 Suite = params{ID: 4, Group: group.P384, Hash: crypto.SHA384}
SuiteP384 Suite = params{id: 4, group: group.P384, hash: crypto.SHA384}
// SuiteP521 represents the OPRF with P-521 and SHA-512.
SuiteP521 Suite = params{ID: 5, Group: group.P521, Hash: crypto.SHA512}
SuiteP521 Suite = params{id: 5, group: group.P521, hash: crypto.SHA512}
)

func GetSuite(id int) (Suite, error) {
switch uint16(id) {
case SuiteP256.(params).ID:
case SuiteP256.(params).id:
return SuiteP256, nil
case SuiteP384.(params).ID:
case SuiteP384.(params).id:
return SuiteP384, nil
case SuiteP521.(params).ID:
case SuiteP521.(params).id:
return SuiteP521, nil
default:
return nil, ErrInvalidSuite
Expand Down Expand Up @@ -164,21 +169,24 @@ func NewPartialObliviousServer(s Suite, key *PrivateKey) PartialObliviousServer
}

type params struct {
ID uint16
id uint16
m Mode
Group group.Group
Hash crypto.Hash
group group.Group
hash crypto.Hash
}

func (p params) cannotBeImplementedExternally() {}

func (p params) String() string { return fmt.Sprintf("Suite%v", p.Group) }
func (p params) String() string { return fmt.Sprintf("Suite%v", p.group) }
func (p params) ID() int { return int(p.id) }
func (p params) Group() group.Group { return p.group }
func (p params) Hash() crypto.Hash { return p.hash }

func (p params) getDST(name string) []byte {
return append(append(append([]byte{},
[]byte(name)...),
[]byte(version)...),
[]byte{p.m, 0, byte(p.ID)}...)
[]byte{p.m, 0, byte(p.id)}...)
}

func (p params) scalarFromInfo(info []byte) (group.Scalar, error) {
Expand All @@ -192,7 +200,7 @@ func (p params) scalarFromInfo(info []byte) (group.Scalar, error) {
lenInfo...),
info...)

return p.Group.HashToScalar(framedInfo, p.getDST(hashToScalarDST)), nil
return p.group.HashToScalar(framedInfo, p.getDST(hashToScalarDST)), nil
}

func (p params) finalizeHash(h hash.Hash, input, info, element []byte) []byte {
Expand All @@ -219,8 +227,8 @@ func (p params) finalizeHash(h hash.Hash, input, info, element []byte) []byte {
}

func (p params) getDLEQParams() (out dleq.Params) {
out.G = p.Group
out.H = p.Hash
out.G = p.group
out.H = p.hash
out.DST = p.getDST("")

return
Expand Down
20 changes: 10 additions & 10 deletions oprf/server.go
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Original file line number Diff line number Diff line change
Expand Up @@ -24,7 +24,7 @@ func (s server) PublicKey() *PublicKey { return s.privateKey.Public() }
func (s server) evaluate(elements []Blinded, secret Blind) []Evaluated {
evaluations := make([]Evaluated, len(elements))
for i := range elements {
evaluations[i] = s.params.Group.NewElement().Mul(elements[i], secret)
evaluations[i] = s.params.group.NewElement().Mul(elements[i], secret)
}

return evaluations
Expand All @@ -41,7 +41,7 @@ func (s VerifiableServer) Evaluate(req *EvaluationRequest) (*Evaluation, error)

proof, err := dleq.Prover{Params: s.getDLEQParams()}.ProveBatch(
s.privateKey.k,
s.params.Group.Generator(),
s.params.group.Generator(),
s.PublicKey().e,
req.Elements,
evaluations,
Expand All @@ -64,8 +64,8 @@ func (s PartialObliviousServer) Evaluate(req *EvaluationRequest, info []byte) (*

proof, err := dleq.Prover{Params: s.getDLEQParams()}.ProveBatch(
keyProof,
s.params.Group.Generator(),
s.params.Group.NewElement().MulGen(keyProof),
s.params.group.Generator(),
s.params.group.NewElement().MulGen(keyProof),
evaluations,
req.Elements,
rand.Reader,
Expand All @@ -82,12 +82,12 @@ func (s server) secretFromInfo(info []byte) (t, tInv group.Scalar, err error) {
if err != nil {
return nil, nil, err
}
t = s.params.Group.NewScalar().Add(m, s.privateKey.k)
t = s.params.group.NewScalar().Add(m, s.privateKey.k)

if zero := s.params.Group.NewScalar(); t.IsEqual(zero) {
if zero := s.params.group.NewScalar(); t.IsEqual(zero) {
return nil, nil, ErrInverseZero
}
tInv = s.params.Group.NewScalar().Inv(t)
tInv = s.params.group.NewScalar().Inv(t)

return t, tInv, nil
}
Expand All @@ -102,14 +102,14 @@ func (s server) fullEvaluate(input, info []byte) ([]byte, error) {
}
}

element := s.params.Group.HashToElement(input, s.params.getDST(hashToGroupDST))
evaluation := s.params.Group.NewElement().Mul(element, evalSecret)
element := s.params.group.HashToElement(input, s.params.getDST(hashToGroupDST))
evaluation := s.params.group.NewElement().Mul(element, evalSecret)
serEval, err := evaluation.MarshalBinaryCompress()
if err != nil {
return nil, err
}

return s.finalizeHash(s.params.Hash.New(), input, info, serEval), nil
return s.finalizeHash(s.params.hash.New(), input, info, serEval), nil
}

func (s Server) FullEvaluate(input []byte) (output []byte, err error) {
Expand Down
14 changes: 7 additions & 7 deletions oprf/vectors_test.go
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Original file line number Diff line number Diff line change
Expand Up @@ -164,33 +164,33 @@ func (v *vector) test(t *testing.T) {

blinds := make([]Blind, len(blindsBytes))
for j := range blindsBytes {
blinds[j] = params.Group.NewScalar()
blinds[j] = params.group.NewScalar()
err := blinds[j].UnmarshalBinary(blindsBytes[j])
test.CheckNoErr(t, err, "invalid blind")
}

finData, evalReq, err := client.blind(inputs, blinds)
test.CheckNoErr(t, err, "invalid client request")
evalReqBytes, err := elementsMarshalBinary(params.Group, evalReq.Elements)
evalReqBytes, err := elementsMarshalBinary(params.group, evalReq.Elements)
test.CheckNoErr(t, err, "bad serialization")
v.compareBytes(t, evalReqBytes, flattenList(t, vi.BlindedElement, "blindedElement"))

eval, err := server.Evaluate(evalReq)
test.CheckNoErr(t, err, "invalid evaluation")
elemBytes, err := elementsMarshalBinary(params.Group, eval.Elements)
elemBytes, err := elementsMarshalBinary(params.group, eval.Elements)
test.CheckNoErr(t, err, "invalid evaluations marshaling")
v.compareBytes(t, elemBytes, flattenList(t, vi.EvaluationElement, "evaluation"))

if v.Mode == VerifiableMode || v.Mode == PartialObliviousMode {
randomness := toScalar(t, params.Group, vi.Proof.R, "invalid proof random scalar")
randomness := toScalar(t, params.group, vi.Proof.R, "invalid proof random scalar")
var proof encoding.BinaryMarshaler
switch v.Mode {
case VerifiableMode:
ss := server.(VerifiableServer)
prover := dleq.Prover{Params: ss.getDLEQParams()}
proof, err = prover.ProveBatchWithRandomness(
ss.privateKey.k,
ss.params.Group.Generator(),
ss.params.group.Generator(),
server.PublicKey().e,
evalReq.Elements,
eval.Elements,
Expand All @@ -201,8 +201,8 @@ func (v *vector) test(t *testing.T) {
prover := dleq.Prover{Params: ss.getDLEQParams()}
proof, err = prover.ProveBatchWithRandomness(
keyProof,
ss.params.Group.Generator(),
ss.params.Group.NewElement().MulGen(keyProof),
ss.params.group.Generator(),
ss.params.group.NewElement().MulGen(keyProof),
eval.Elements,
evalReq.Elements,
randomness)
Expand Down