mirror of
https://github.com/golang/go
synced 2024-11-22 01:14:40 -07:00
crypto/dsa: add support for DSA
R=bradfitzgo, r, bradfitzwork, nsz, rsc CC=golang-dev https://golang.org/cl/3990043
This commit is contained in:
Adam Langley
parent
d0e6c7e134
commit
166008b988
@ -33,6 +33,7 @@ DIRS=\
|
||||
crypto/blowfish\
|
||||
crypto/cast5\
|
||||
crypto/cipher\
|
||||
crypto/dsa\
|
||||
crypto/elliptic\
|
||||
crypto/hmac\
|
||||
crypto/md4\
|
||||
|
||||
11
src/pkg/crypto/dsa/Makefile
Normal file
11
src/pkg/crypto/dsa/Makefile
Normal file
@ -0,0 +1,11 @@
|
||||
# Copyright 2011 The Go Authors. All rights reserved.
|
||||
# Use of this source code is governed by a BSD-style
|
||||
# license that can be found in the LICENSE file.
|
||||
|
||||
include ../../../Make.inc
|
||||
|
||||
TARG=crypto/dsa
|
||||
GOFILES=\
|
||||
dsa.go\
|
||||
|
||||
include ../../../Make.pkg
|
||||
276
src/pkg/crypto/dsa/dsa.go
Normal file
276
src/pkg/crypto/dsa/dsa.go
Normal file
@ -0,0 +1,276 @@
|
||||
// Copyright 2011 The Go Authors. All rights reserved.
|
||||
// Use of this source code is governed by a BSD-style
|
||||
// license that can be found in the LICENSE file.
|
||||
|
||||
// Package dsa implements the Digital Signature Algorithm, as defined in FIPS 186-3
|
||||
package dsa
|
||||
|
||||
import (
|
||||
"big"
|
||||
"io"
|
||||
"os"
|
||||
)
|
||||
|
||||
// Parameters represents the domain parameters for a key. These parameters can
|
||||
// be shared across many keys. The bit length of Q must be a multiple of 8.
|
||||
type Parameters struct {
|
||||
P, Q, G *big.Int
|
||||
}
|
||||
|
||||
// PublicKey represents a DSA public key.
|
||||
type PublicKey struct {
|
||||
Parameters
|
||||
Y *big.Int
|
||||
}
|
||||
|
||||
// PrivateKey represents a DSA private key.
|
||||
type PrivateKey struct {
|
||||
PublicKey
|
||||
X *big.Int
|
||||
}
|
||||
|
||||
type invalidPublicKeyError int
|
||||
|
||||
func (invalidPublicKeyError) String() string {
|
||||
return "crypto/dsa: invalid public key"
|
||||
}
|
||||
|
||||
// InvalidPublicKeyError results when a public key is not usable by this code.
|
||||
// FIPS is quite strict about the format of DSA keys, but other code may be
|
||||
// less so. Thus, when using keys which may have been generated by other code,
|
||||
// this error must be handled.
|
||||
var InvalidPublicKeyError = invalidPublicKeyError(0)
|
||||
|
||||
// ParameterSizes is a enumeration of the acceptable bit lengths of the primes
|
||||
// in a set of DSA parameters. See FIPS 186-3, section 4.2.
|
||||
type ParameterSizes int
|
||||
|
||||
const (
|
||||
L1024N160 ParameterSizes = iota
|
||||
L2048N224
|
||||
L2048N256
|
||||
L3072N256
|
||||
)
|
||||
|
||||
// numMRTests is the number of Miller-Rabin primality tests that we perform. We
|
||||
// pick the largest recommended number from table C.1 of FIPS 186-3.
|
||||
const numMRTests = 64
|
||||
|
||||
// GenerateParameters puts a random, valid set of DSA parameters into params.
|
||||
// This function takes many seconds, even on fast machines.
|
||||
func GenerateParameters(params *Parameters, rand io.Reader, sizes ParameterSizes) (err os.Error) {
|
||||
// This function doesn't follow FIPS 186-3 exactly in that it doesn't
|
||||
// use a verification seed to generate the primes. The verification
|
||||
// seed doesn't appear to be exported or used by other code and
|
||||
// omitting it makes the code cleaner.
|
||||
|
||||
var L, N int
|
||||
switch sizes {
|
||||
case L1024N160:
|
||||
L = 1024
|
||||
N = 160
|
||||
case L2048N224:
|
||||
L = 2048
|
||||
N = 224
|
||||
case L2048N256:
|
||||
L = 2048
|
||||
N = 256
|
||||
case L3072N256:
|
||||
L = 3072
|
||||
N = 256
|
||||
default:
|
||||
return os.ErrorString("crypto/dsa: invalid ParameterSizes")
|
||||
}
|
||||
|
||||
qBytes := make([]byte, N/8)
|
||||
pBytes := make([]byte, L/8)
|
||||
|
||||
q := new(big.Int)
|
||||
p := new(big.Int)
|
||||
rem := new(big.Int)
|
||||
one := new(big.Int)
|
||||
one.SetInt64(1)
|
||||
|
||||
GeneratePrimes:
|
||||
for {
|
||||
_, err = io.ReadFull(rand, qBytes)
|
||||
if err != nil {
|
||||
return
|
||||
}
|
||||
|
||||
qBytes[len(qBytes)-1] |= 1
|
||||
qBytes[0] |= 0x80
|
||||
q.SetBytes(qBytes)
|
||||
|
||||
if !big.ProbablyPrime(q, numMRTests) {
|
||||
continue
|
||||
}
|
||||
|
||||
for i := 0; i < 4*L; i++ {
|
||||
_, err = io.ReadFull(rand, pBytes)
|
||||
if err != nil {
|
||||
return
|
||||
}
|
||||
|
||||
pBytes[len(pBytes)-1] |= 1
|
||||
pBytes[0] |= 0x80
|
||||
|
||||
p.SetBytes(pBytes)
|
||||
rem.Mod(p, q)
|
||||
rem.Sub(rem, one)
|
||||
p.Sub(p, rem)
|
||||
if p.BitLen() < L {
|
||||
continue
|
||||
}
|
||||
|
||||
if !big.ProbablyPrime(p, numMRTests) {
|
||||
continue
|
||||
}
|
||||
|
||||
params.P = p
|
||||
params.Q = q
|
||||
break GeneratePrimes
|
||||
}
|
||||
}
|
||||
|
||||
h := new(big.Int)
|
||||
h.SetInt64(2)
|
||||
g := new(big.Int)
|
||||
|
||||
pm1 := new(big.Int).Sub(p, one)
|
||||
e := new(big.Int).Div(pm1, q)
|
||||
|
||||
for {
|
||||
g.Exp(h, e, p)
|
||||
if g.Cmp(one) == 0 {
|
||||
h.Add(h, one)
|
||||
continue
|
||||
}
|
||||
|
||||
params.G = g
|
||||
return
|
||||
}
|
||||
|
||||
panic("unreachable")
|
||||
}
|
||||
|
||||
// GenerateKey generates a public&private key pair. The Parameters of the
|
||||
// PrivateKey must already be valid (see GenerateParameters).
|
||||
func GenerateKey(priv *PrivateKey, rand io.Reader) os.Error {
|
||||
if priv.P == nil || priv.Q == nil || priv.G == nil {
|
||||
return os.ErrorString("crypto/dsa: parameters not set up before generating key")
|
||||
}
|
||||
|
||||
x := new(big.Int)
|
||||
xBytes := make([]byte, priv.Q.BitLen()/8)
|
||||
|
||||
for {
|
||||
_, err := io.ReadFull(rand, xBytes)
|
||||
if err != nil {
|
||||
return err
|
||||
}
|
||||
x.SetBytes(xBytes)
|
||||
if x.Sign() != 0 && x.Cmp(priv.Q) < 0 {
|
||||
break
|
||||
}
|
||||
}
|
||||
|
||||
priv.X = x
|
||||
priv.Y = new(big.Int)
|
||||
priv.Y.Exp(priv.G, x, priv.P)
|
||||
return nil
|
||||
}
|
||||
|
||||
// Sign signs an arbitrary length hash (which should be the result of hashing a
|
||||
// larger message) using the private key, priv. It returns the signature as a
|
||||
// pair of integers. The security of the private key depends on the entropy of
|
||||
// rand.
|
||||
func Sign(rand io.Reader, priv *PrivateKey, hash []byte) (r, s *big.Int, err os.Error) {
|
||||
// FIPS 186-3, section 4.6
|
||||
|
||||
n := priv.Q.BitLen()
|
||||
if n&7 != 0 {
|
||||
err = InvalidPublicKeyError
|
||||
return
|
||||
}
|
||||
n >>= 3
|
||||
|
||||
for {
|
||||
k := new(big.Int)
|
||||
buf := make([]byte, n)
|
||||
for {
|
||||
_, err = io.ReadFull(rand, buf)
|
||||
if err != nil {
|
||||
return
|
||||
}
|
||||
k.SetBytes(buf)
|
||||
if k.Sign() > 0 && k.Cmp(priv.Q) < 0 {
|
||||
break
|
||||
}
|
||||
}
|
||||
|
||||
kInv := new(big.Int).ModInverse(k, priv.Q)
|
||||
|
||||
r = new(big.Int).Exp(priv.G, k, priv.P)
|
||||
r.Mod(r, priv.Q)
|
||||
|
||||
if r.Sign() == 0 {
|
||||
continue
|
||||
}
|
||||
|
||||
if n > len(hash) {
|
||||
n = len(hash)
|
||||
}
|
||||
z := k.SetBytes(hash[:n])
|
||||
|
||||
s = new(big.Int).Mul(priv.X, r)
|
||||
s.Add(s, z)
|
||||
s.Mod(s, priv.Q)
|
||||
s.Mul(s, kInv)
|
||||
s.Mod(s, priv.Q)
|
||||
|
||||
if s.Sign() != 0 {
|
||||
break
|
||||
}
|
||||
}
|
||||
|
||||
return
|
||||
}
|
||||
|
||||
// Verify verifies the signature in r, s of hash using the public key, pub. It
|
||||
// returns true iff the signature is valid.
|
||||
func Verify(pub *PublicKey, hash []byte, r, s *big.Int) bool {
|
||||
// FIPS 186-3, section 4.7
|
||||
|
||||
if r.Sign() < 1 || r.Cmp(pub.Q) >= 0 {
|
||||
return false
|
||||
}
|
||||
if s.Sign() < 1 || s.Cmp(pub.Q) >= 0 {
|
||||
return false
|
||||
}
|
||||
|
||||
w := new(big.Int).ModInverse(s, pub.Q)
|
||||
|
||||
n := pub.Q.BitLen()
|
||||
if n&7 != 0 {
|
||||
return false
|
||||
}
|
||||
n >>= 3
|
||||
|
||||
if n > len(hash) {
|
||||
n = len(hash)
|
||||
}
|
||||
z := new(big.Int).SetBytes(hash[:n])
|
||||
|
||||
u1 := new(big.Int).Mul(z, w)
|
||||
u1.Mod(u1, pub.Q)
|
||||
u2 := w.Mul(r, w)
|
||||
u2.Mod(u2, pub.Q)
|
||||
v := u1.Exp(pub.G, u1, pub.P)
|
||||
u2.Exp(pub.Y, u2, pub.P)
|
||||
v.Mul(v, u2)
|
||||
v.Mod(v, pub.P)
|
||||
v.Mod(v, pub.Q)
|
||||
|
||||
return v.Cmp(r) == 0
|
||||
}
|
||||
84
src/pkg/crypto/dsa/dsa_test.go
Normal file
84
src/pkg/crypto/dsa/dsa_test.go
Normal file
@ -0,0 +1,84 @@
|
||||
// Copyright 2011 The Go Authors. All rights reserved.
|
||||
// Use of this source code is governed by a BSD-style
|
||||
// license that can be found in the LICENSE file.
|
||||
|
||||
package dsa
|
||||
|
||||
import (
|
||||
"big"
|
||||
"crypto/rand"
|
||||
"testing"
|
||||
)
|
||||
|
||||
func testSignAndVerify(t *testing.T, i int, priv *PrivateKey) {
|
||||
hashed := []byte("testing")
|
||||
r, s, err := Sign(rand.Reader, priv, hashed)
|
||||
if err != nil {
|
||||
t.Errorf("%d: error signing: %s", i, err)
|
||||
return
|
||||
}
|
||||
|
||||
if !Verify(&priv.PublicKey, hashed, r, s) {
|
||||
t.Errorf("%d: Verify failed", i)
|
||||
}
|
||||
}
|
||||
|
||||
func testParameterGeneration(t *testing.T, sizes ParameterSizes, L, N int) {
|
||||
var priv PrivateKey
|
||||
params := &priv.Parameters
|
||||
|
||||
err := GenerateParameters(params, rand.Reader, sizes)
|
||||
if err != nil {
|
||||
t.Errorf("%d: %s", int(sizes), err)
|
||||
return
|
||||
}
|
||||
|
||||
if params.P.BitLen() != L {
|
||||
t.Errorf("%d: params.BitLen got:%d want:%d", int(sizes), params.P.BitLen(), L)
|
||||
}
|
||||
|
||||
if params.Q.BitLen() != N {
|
||||
t.Errorf("%d: q.BitLen got:%d want:%d", int(sizes), params.Q.BitLen(), L)
|
||||
}
|
||||
|
||||
one := new(big.Int)
|
||||
one.SetInt64(1)
|
||||
pm1 := new(big.Int).Sub(params.P, one)
|
||||
quo, rem := new(big.Int).DivMod(pm1, params.Q, new(big.Int))
|
||||
if rem.Sign() != 0 {
|
||||
t.Errorf("%d: p-1 mod q != 0", int(sizes))
|
||||
}
|
||||
x := new(big.Int).Exp(params.G, quo, params.P)
|
||||
if x.Cmp(one) == 0 {
|
||||
t.Errorf("%d: invalid generator", int(sizes))
|
||||
}
|
||||
|
||||
err = GenerateKey(&priv, rand.Reader)
|
||||
if err != nil {
|
||||
t.Errorf("error generating key: %s", err)
|
||||
return
|
||||
}
|
||||
|
||||
testSignAndVerify(t, int(sizes), &priv)
|
||||
}
|
||||
|
||||
func TestParameterGeneration(t *testing.T) {
|
||||
// This test is too slow to run all the time.
|
||||
return
|
||||
|
||||
testParameterGeneration(t, L1024N160, 1024, 160)
|
||||
testParameterGeneration(t, L2048N224, 2048, 224)
|
||||
testParameterGeneration(t, L2048N256, 2048, 256)
|
||||
testParameterGeneration(t, L3072N256, 3072, 256)
|
||||
}
|
||||
|
||||
func TestSignAndVerify(t *testing.T) {
|
||||
var priv PrivateKey
|
||||
priv.P, _ = new(big.Int).SetString("A9B5B793FB4785793D246BAE77E8FF63CA52F442DA763C440259919FE1BC1D6065A9350637A04F75A2F039401D49F08E066C4D275A5A65DA5684BC563C14289D7AB8A67163BFBF79D85972619AD2CFF55AB0EE77A9002B0EF96293BDD0F42685EBB2C66C327079F6C98000FBCB79AACDE1BC6F9D5C7B1A97E3D9D54ED7951FEF", 16)
|
||||
priv.Q, _ = new(big.Int).SetString("E1D3391245933D68A0714ED34BBCB7A1F422B9C1", 16)
|
||||
priv.G, _ = new(big.Int).SetString("634364FC25248933D01D1993ECABD0657CC0CB2CEED7ED2E3E8AECDFCDC4A25C3B15E9E3B163ACA2984B5539181F3EFF1A5E8903D71D5B95DA4F27202B77D2C44B430BB53741A8D59A8F86887525C9F2A6A5980A195EAA7F2FF910064301DEF89D3AA213E1FAC7768D89365318E370AF54A112EFBA9246D9158386BA1B4EEFDA", 16)
|
||||
priv.Y, _ = new(big.Int).SetString("32969E5780CFE1C849A1C276D7AEB4F38A23B591739AA2FE197349AEEBD31366AEE5EB7E6C6DDB7C57D02432B30DB5AA66D9884299FAA72568944E4EEDC92EA3FBC6F39F53412FBCC563208F7C15B737AC8910DBC2D9C9B8C001E72FDC40EB694AB1F06A5A2DBD18D9E36C66F31F566742F11EC0A52E9F7B89355C02FB5D32D2", 16)
|
||||
priv.X, _ = new(big.Int).SetString("5078D4D29795CBE76D3AACFE48C9AF0BCDBEE91A", 16)
|
||||
|
||||
testSignAndVerify(t, 0, &priv)
|
||||
}
|
||||
Loading…
Reference in New Issue
Block a user