diff options
Diffstat (limited to 'src/pkg/crypto/dsa')
-rw-r--r-- | src/pkg/crypto/dsa/dsa.go | 278 | ||||
-rw-r--r-- | src/pkg/crypto/dsa/dsa_test.go | 85 |
2 files changed, 0 insertions, 363 deletions
diff --git a/src/pkg/crypto/dsa/dsa.go b/src/pkg/crypto/dsa/dsa.go deleted file mode 100644 index b7565a61b..000000000 --- a/src/pkg/crypto/dsa/dsa.go +++ /dev/null @@ -1,278 +0,0 @@ -// 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 ( - "errors" - "io" - "math/big" -) - -// 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 -} - -// ErrInvalidPublicKey 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 ErrInvalidPublicKey = errors.New("crypto/dsa: invalid public key") - -// 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 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 errors.New("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 !q.ProbablyPrime(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 !p.ProbablyPrime(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 - } -} - -// 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) error { - if priv.P == nil || priv.Q == nil || priv.G == nil { - return errors.New("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 -} - -// fermatInverse calculates the inverse of k in GF(P) using Fermat's method. -// This has better constant-time properties than Euclid's method (implemented -// in math/big.Int.ModInverse) although math/big itself isn't strictly -// constant-time so it's not perfect. -func fermatInverse(k, P *big.Int) *big.Int { - two := big.NewInt(2) - pMinus2 := new(big.Int).Sub(P, two) - return new(big.Int).Exp(k, pMinus2, P) -} - -// 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. -// -// Note that FIPS 186-3 section 4.6 specifies that the hash should be truncated -// to the byte-length of the subgroup. This function does not perform that -// truncation itself. -func Sign(rand io.Reader, priv *PrivateKey, hash []byte) (r, s *big.Int, err error) { - // FIPS 186-3, section 4.6 - - n := priv.Q.BitLen() - if n&7 != 0 { - err = ErrInvalidPublicKey - 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 := fermatInverse(k, priv.Q) - - r = new(big.Int).Exp(priv.G, k, priv.P) - r.Mod(r, priv.Q) - - if r.Sign() == 0 { - continue - } - - z := k.SetBytes(hash) - - 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 -// reports whether the signature is valid. -// -// Note that FIPS 186-3 section 4.6 specifies that the hash should be truncated -// to the byte-length of the subgroup. This function does not perform that -// truncation itself. -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 - } - z := new(big.Int).SetBytes(hash) - - 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 -} diff --git a/src/pkg/crypto/dsa/dsa_test.go b/src/pkg/crypto/dsa/dsa_test.go deleted file mode 100644 index 568416d0d..000000000 --- a/src/pkg/crypto/dsa/dsa_test.go +++ /dev/null @@ -1,85 +0,0 @@ -// 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 ( - "crypto/rand" - "math/big" - "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) { - if testing.Short() { - t.Skip("skipping parameter generation test in short mode") - } - - 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) -} |