test case for auth challenge

auth_challenge.go

@@ -299,32 +299,47 @@ func (a AuthRSASHA256TLSSecret) Body() ([]byte, error) {
 
 	io.CopyN(&buf, cryptorand.Reader, 24)
 
-	//	       SIG: A signature of a SHA256 hash of all the previous fields
-	//	         using the initiator's "Authenticate" key as presented.  (As
-	//	         always in Tor, we use OAEP-MGF1 padding; see tor-spec.txt
-	//	         section 0.3.)
-	// TODO(mbm): I'm not sure what OAEP means here. TvdW seems to be using PKCS padding.
-	digest := sha256.Sum256(buf.Bytes())
-	sig, err := rsa.SignPKCS1v15(nil, a.AuthKey, 0, digest[:])
+	return buf.Bytes(), nil
+}
+
+func (a AuthRSASHA256TLSSecret) SignedBody() ([]byte, error) {
+	body, err := a.Body()
 	if err != nil {
 		return nil, err
 	}
-	buf.Write(sig)
 
-	return buf.Bytes(), nil
+	sig, err := torcrypto.SignRSASHA256(body, a.AuthKey)
+	if err != nil {
+		return nil, err
+	}
+
+	return append(body, sig...), nil
 }
 
 func (a AuthRSASHA256TLSSecret) Cell(f CellFormat) (Cell, error) {
-	body, err := a.Body()
+	body, err := a.SignedBody()
 	if err != nil {
 		return nil, err
 	}
 
-	debug.DumpBytes("auth_body", body)
-
 	c := &AuthenticateCell{
 		Method:         AuthMethodRSASHA256TLSSecret,
 		Authentication: body,
 	}
 	return c.Cell(f)
 }
+
+func (a AuthRSASHA256TLSSecret) GoString() string {
+	s := "AuthRSASHA256TLSSecret{\n"
+	s += "\tAuthKey: " + debug.GoStringRSAPrivateKey(a.AuthKey) + ",\n"
+	s += "\tClientIdentityKey: " + debug.GoStringRSAPublicKey(a.ClientIdentityKey) + ",\n"
+	s += "\tServerIdentityKey: " + debug.GoStringRSAPublicKey(a.ServerIdentityKey) + ",\n"
+	s += "\tServerLogHash: " + debug.GoStringByteArray(a.ServerLogHash) + ",\n"
+	s += "\tClientLogHash: " + debug.GoStringByteArray(a.ClientLogHash) + ",\n"
+	s += "\tServerLinkCert: " + debug.GoStringByteArray(a.ServerLinkCert) + ",\n"
+	s += "\tTLSMasterSecret: " + debug.GoStringByteArray(a.TLSMasterSecret) + ",\n"
+	s += "\tTLSClientRandom: " + debug.GoStringByteArray(a.TLSClientRandom) + ",\n"
+	s += "\tTLSServerRandom: " + debug.GoStringByteArray(a.TLSServerRandom) + ",\n"
+	s += "}"
+	return s
+}

auth_challenge_test.go

@@ -3,6 +3,7 @@ package pearl
 import (
 	"testing"
 
+	"github.com/mmcloughlin/pearl/torcrypto"
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
 )
@@ -53,3 +54,98 @@ func TestAuthenticateCellRoundTrip(t *testing.T) {
 	require.NoError(t, err)
 	assert.Equal(t, c.Bytes(), c2.Bytes())
 }
+
+func TestAuthRSASHA256TLSSecret(t *testing.T) {
+	a := AuthRSASHA256TLSSecret{
+		AuthKey:           torcrypto.MustRSAPrivateKey(torcrypto.ParseRSAPrivateKeyPKCS1PEM([]byte("-----BEGIN RSA PRIVATE KEY-----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\nHr3hF+LrpR3nWVwuZcsAcDb4xAI6KvEuFDZ1l+no5m0=\n-----END RSA PRIVATE KEY-----\n"))),
+		ClientIdentityKey: torcrypto.MustRSAPublicKey(torcrypto.ParseRSAPublicKeyPKCS1PEM([]byte("-----BEGIN RSA PUBLIC KEY-----\nMIGJAoGBALaKBJ/sK8zr+0j7ih0YWk7jHLDYnZSBvseoRmUfTOuxkj8LOce8X/GG\nLPYMFJUTNL0ToQApC6TqbEuShzQyQLk9IHWRhVsmSDKYjLZepzdsvJx8gL5QaHea\nf5Ge3nmo+oUKdeX3rDQd07us/nLja3VUL2xKdd+hE81KMxhTjG4RAgMBAAE=\n-----END RSA PUBLIC KEY-----\n"))),
+		ServerIdentityKey: torcrypto.MustRSAPublicKey(torcrypto.ParseRSAPublicKeyPKCS1PEM([]byte("-----BEGIN RSA PUBLIC KEY-----\nMIGJAoGBALMlpknZ4yhwp7TcjAAZjIcgyjqjSd4BJqbLWvhEFWvM5rhO+DWkLfuM\nssdS6FimnN5oItUYVx0W4RPKyuVeqdUK0F2gj+yVtgA5cUXAhhrJUQp4o4JBFrH3\ntivLapYfvNvhpT/Xo6kBeu29LwxYWgVYrKAK/d9RRVE9lJ1SOxuHAgMBAAE=\n-----END RSA PUBLIC KEY-----\n"))),
+		ServerLogHash: []byte{
+			0x3d, 0xff, 0xfa, 0x23, 0x44, 0x11, 0x38, 0x21, 0x67, 0x22, 0xb5, 0xe3, 0xdb, 0xb8, 0x66, 0x44,
+			0x87, 0x0e, 0x41, 0x15, 0x72, 0x96, 0xde, 0x70, 0x14, 0xe8, 0xc4, 0x72, 0x99, 0x96, 0x8c, 0xa9,
+		},
+		ClientLogHash: []byte{
+			0x36, 0x3f, 0xce, 0x3f, 0x6b, 0xd7, 0x2c, 0x9c, 0x25, 0x25, 0xd1, 0x07, 0x47, 0x3a, 0x97, 0xb5,
+			0xbc, 0x1a, 0xfd, 0xba, 0xce, 0xe7, 0xb3, 0xde, 0x3c, 0xdf, 0x01, 0xa0, 0xd1, 0x4c, 0x70, 0xaf,
+		},
+		ServerLinkCert: []byte{
+			0x30, 0x82, 0x02, 0x45, 0x30, 0x82, 0x01, 0xae, 0xa0, 0x03, 0x02, 0x01, 0x02, 0x02, 0x08, 0x4e,
+			0xbe, 0xe3, 0xc7, 0xa4, 0xcc, 0x0a, 0x73, 0x30, 0x0d, 0x06, 0x09, 0x2a, 0x86, 0x48, 0x86, 0xf7,
+			0x0d, 0x01, 0x01, 0x0b, 0x05, 0x00, 0x30, 0x22, 0x31, 0x20, 0x30, 0x1e, 0x06, 0x03, 0x55, 0x04,
+			0x03, 0x0c, 0x17, 0x77, 0x77, 0x77, 0x2e, 0x64, 0x73, 0x68, 0x7a, 0x6c, 0x78, 0x69, 0x67, 0x6f,
+			0x71, 0x63, 0x36, 0x7a, 0x7a, 0x73, 0x2e, 0x63, 0x6f, 0x6d, 0x30, 0x1e, 0x17, 0x0d, 0x31, 0x37,
+			0x30, 0x35, 0x31, 0x35, 0x30, 0x30, 0x30, 0x30, 0x30, 0x30, 0x5a, 0x17, 0x0d, 0x31, 0x38, 0x30,
+			0x35, 0x30, 0x36, 0x32, 0x33, 0x35, 0x39, 0x35, 0x39, 0x5a, 0x30, 0x24, 0x31, 0x22, 0x30, 0x20,
+			0x06, 0x03, 0x55, 0x04, 0x03, 0x0c, 0x19, 0x77, 0x77, 0x77, 0x2e, 0x67, 0x79, 0x36, 0x65, 0x34,
+			0x35, 0x6e, 0x68, 0x75, 0x35, 0x76, 0x62, 0x7a, 0x61, 0x33, 0x37, 0x68, 0x2e, 0x6e, 0x65, 0x74,
+			0x30, 0x82, 0x01, 0x22, 0x30, 0x0d, 0x06, 0x09, 0x2a, 0x86, 0x48, 0x86, 0xf7, 0x0d, 0x01, 0x01,
+			0x01, 0x05, 0x00, 0x03, 0x82, 0x01, 0x0f, 0x00, 0x30, 0x82, 0x01, 0x0a, 0x02, 0x82, 0x01, 0x01,
+			0x00, 0xa6, 0x0f, 0x46, 0xf4, 0xff, 0xd5, 0xe1, 0x22, 0xdc, 0x5e, 0x8e, 0x7c, 0x3c, 0x54, 0x61,
+			0xf8, 0xdc, 0x56, 0xda, 0x93, 0x55, 0xf3, 0x40, 0x14, 0xf8, 0xc7, 0xca, 0x6b, 0xea, 0x26, 0xf5,
+			0x24, 0x55, 0x9e, 0x34, 0x1d, 0x7f, 0x86, 0xd8, 0x0c, 0xb0, 0x01, 0xdb, 0xb6, 0x12, 0x99, 0xe1,
+			0xc4, 0x2e, 0x03, 0xb7, 0x32, 0x59, 0x49, 0xc5, 0xb0, 0x02, 0x0d, 0x51, 0x2f, 0xf1, 0xf3, 0x15,
+			0x5d, 0xc0, 0x5d, 0x49, 0x76, 0xab, 0xad, 0xf9, 0xbb, 0x2a, 0x53, 0xb2, 0x58, 0x24, 0xf4, 0x90,
+			0x22, 0xea, 0xff, 0xa3, 0x53, 0xae, 0x41, 0x18, 0xee, 0x82, 0x99, 0x3b, 0x0d, 0x12, 0x67, 0x90,
+			0x25, 0x25, 0x04, 0x55, 0x2f, 0x72, 0xca, 0x21, 0x7f, 0xc5, 0x58, 0xab, 0x58, 0x66, 0x16, 0x11,
+			0x54, 0x24, 0xc9, 0x24, 0xf5, 0x0a, 0x86, 0xef, 0x12, 0x43, 0xad, 0x88, 0x71, 0x21, 0x81, 0xe8,
+			0x6f, 0x1f, 0x95, 0x1a, 0x4a, 0x1f, 0x57, 0x7c, 0x0e, 0x4b, 0x99, 0x7b, 0x18, 0x0c, 0xe4, 0x87,
+			0xbd, 0xee, 0x6c, 0x60, 0x37, 0xd3, 0x02, 0x71, 0x32, 0x9f, 0x7e, 0x88, 0xac, 0x22, 0x36, 0x9e,
+			0xad, 0x29, 0x2d, 0xcc, 0xf5, 0xd0, 0x8f, 0xf8, 0x26, 0x7f, 0x3b, 0x43, 0xbc, 0x30, 0x54, 0x15,
+			0xab, 0x46, 0x73, 0x8c, 0x85, 0x4d, 0xa4, 0x49, 0xb0, 0x21, 0x4a, 0xde, 0xe8, 0xf0, 0x5c, 0x14,
+			0x4e, 0x5f, 0xae, 0x3d, 0x28, 0xd6, 0xc1, 0x1c, 0x02, 0x2d, 0x3c, 0xed, 0xf5, 0xbb, 0x1e, 0x69,
+			0x21, 0x23, 0x21, 0x13, 0xdf, 0x98, 0x96, 0xbf, 0x64, 0x33, 0x7e, 0x04, 0xa9, 0x6c, 0xea, 0x08,
+			0x25, 0x05, 0x07, 0x0f, 0x1f, 0xb9, 0x60, 0x47, 0xbb, 0x32, 0x3d, 0x7a, 0x41, 0x62, 0x40, 0x11,
+			0x26, 0xdf, 0x0e, 0xfe, 0x3b, 0x62, 0x17, 0x6d, 0x9a, 0xaf, 0x2b, 0xc3, 0xaa, 0x66, 0xc5, 0x3c,
+			0x0d, 0x02, 0x03, 0x01, 0x00, 0x01, 0x30, 0x0d, 0x06, 0x09, 0x2a, 0x86, 0x48, 0x86, 0xf7, 0x0d,
+			0x01, 0x01, 0x0b, 0x05, 0x00, 0x03, 0x81, 0x81, 0x00, 0x3f, 0x2d, 0x88, 0x9d, 0x1a, 0x6f, 0xec,
+			0x3c, 0x8a, 0x91, 0x93, 0x48, 0xe3, 0xd2, 0x3c, 0x69, 0xd3, 0x90, 0x62, 0x44, 0x19, 0xe8, 0xc6,
+			0x5f, 0x6f, 0x0e, 0x61, 0xe4, 0xbb, 0x68, 0x25, 0xaa, 0x71, 0xa2, 0x1d, 0x55, 0x09, 0x75, 0x94,
+			0x90, 0xd0, 0xb6, 0xcf, 0xe3, 0xc8, 0xbd, 0xaf, 0x97, 0x68, 0xd8, 0x5b, 0xd7, 0xbc, 0xd3, 0x40,
+			0xcc, 0x13, 0x80, 0xcd, 0xa9, 0xe7, 0xfc, 0x98, 0xe7, 0x7d, 0xc2, 0xdf, 0x17, 0xcc, 0x66, 0x7e,
+			0xa6, 0xe4, 0x31, 0xd7, 0xe9, 0xfb, 0x30, 0x4a, 0x0c, 0x19, 0x4f, 0x7a, 0x21, 0x6f, 0x77, 0x06,
+			0xd5, 0xa2, 0x79, 0x62, 0x1d, 0xde, 0xdd, 0x82, 0xfc, 0x2c, 0x0b, 0x07, 0x3c, 0xcc, 0x71, 0xc4,
+			0x29, 0x58, 0x64, 0x90, 0x9f, 0x4a, 0x63, 0x69, 0x7d, 0x3e, 0x3b, 0x58, 0x51, 0x41, 0x7e, 0x1d,
+			0x91, 0x4f, 0xde, 0x54, 0xb4, 0xb1, 0x24, 0x54, 0x2c,
+		},
+		TLSMasterSecret: []byte{
+			0xb3, 0x2a, 0x03, 0xf4, 0x8d, 0xdd, 0x8a, 0x27, 0x29, 0x21, 0xb2, 0x54, 0x44, 0xa4, 0x99, 0x24,
+			0x17, 0x64, 0x72, 0x31, 0xf7, 0x93, 0x3f, 0x0c, 0x1e, 0x3c, 0x28, 0xc1, 0x53, 0xc9, 0x40, 0xfc,
+			0x4e, 0x92, 0x47, 0x81, 0x1a, 0x8d, 0x88, 0x97, 0xd4, 0xd1, 0x65, 0x36, 0x38, 0x4d, 0xfd, 0x13,
+		},
+		TLSClientRandom: []byte{
+			0xf0, 0xed, 0x85, 0x5c, 0x8e, 0xe0, 0x6d, 0x22, 0xa6, 0xdf, 0x4d, 0x36, 0x7e, 0xfa, 0x21, 0x8b,
+			0x15, 0x93, 0x71, 0xb9, 0x4a, 0xa7, 0xf6, 0x6c, 0x73, 0x16, 0x09, 0x38, 0x33, 0x43, 0xb9, 0xb4,
+		},
+		TLSServerRandom: []byte{
+			0xca, 0xc6, 0xa4, 0xe5, 0xeb, 0x1e, 0xaf, 0x35, 0xec, 0xed, 0x76, 0xf2, 0x8b, 0x0b, 0xa0, 0x87,
+			0x70, 0x8d, 0xe1, 0x00, 0xa7, 0x60, 0x7f, 0xe5, 0x6a, 0x49, 0xe1, 0x08, 0xe6, 0x7a, 0x36, 0x77,
+		},
+	}
+
+	expect := []byte{
+		0x41, 0x55, 0x54, 0x48, 0x30, 0x30, 0x30, 0x31, 0x2a, 0x90, 0x7f, 0x75,
+		0x1f, 0x6a, 0xd4, 0x1d, 0xac, 0xb6, 0x8a, 0x23, 0x1d, 0xcd, 0x27, 0x86,
+		0xd5, 0x32, 0xac, 0xc7, 0x1c, 0x4b, 0x25, 0xfe, 0x86, 0x42, 0xe0, 0x2d,
+		0x25, 0x29, 0x8b, 0x71, 0x91, 0x3b, 0x62, 0x54, 0xb6, 0x9f, 0xfc, 0xad,
+		0xc3, 0x40, 0x69, 0x9c, 0xd5, 0x4a, 0xd7, 0x1d, 0xfc, 0xcd, 0x26, 0x8e,
+		0xa8, 0xed, 0xa2, 0x3a, 0x81, 0x68, 0x1f, 0x00, 0x10, 0x37, 0x47, 0xf3,
+		0x3d, 0xff, 0xfa, 0x23, 0x44, 0x11, 0x38, 0x21, 0x67, 0x22, 0xb5, 0xe3,
+		0xdb, 0xb8, 0x66, 0x44, 0x87, 0x0e, 0x41, 0x15, 0x72, 0x96, 0xde, 0x70,
+		0x14, 0xe8, 0xc4, 0x72, 0x99, 0x96, 0x8c, 0xa9, 0x36, 0x3f, 0xce, 0x3f,
+		0x6b, 0xd7, 0x2c, 0x9c, 0x25, 0x25, 0xd1, 0x07, 0x47, 0x3a, 0x97, 0xb5,
+		0xbc, 0x1a, 0xfd, 0xba, 0xce, 0xe7, 0xb3, 0xde, 0x3c, 0xdf, 0x01, 0xa0,
+		0xd1, 0x4c, 0x70, 0xaf, 0xc4, 0xd7, 0x72, 0xe8, 0x60, 0xcc, 0x74, 0xde,
+		0xa7, 0x93, 0xfb, 0xd5, 0xd6, 0x39, 0xe0, 0x16, 0x1f, 0x4c, 0x0d, 0x42,
+		0x23, 0x6c, 0xb8, 0x17, 0x9d, 0xd0, 0xdd, 0x29, 0x88, 0x94, 0x7e, 0x7c,
+		0x1b, 0xbc, 0xae, 0xdf, 0xb8, 0x38, 0xc7, 0x25, 0x9a, 0x39, 0x46, 0xc6,
+		0x42, 0x3c, 0x3d, 0x96, 0xe1, 0xd3, 0xb8, 0x21, 0xbb, 0x5b, 0xef, 0x18,
+		0xdd, 0x21, 0xe2, 0x41, 0xdc, 0x5f, 0x6e, 0xd1, 0x5b, 0x9c, 0xd0, 0xc4,
+		0x8a, 0x90, 0xc6, 0x1a, 0x60, 0x8d, 0x94, 0x6d, 0xe0, 0xfa, 0xc5, 0x90,
+		0x7c, 0x25, 0x74, 0x34, 0x8d, 0xb7, 0x0e, 0x99,
+	}
+
+	body, err := a.Body()
+	require.NoError(t, err)
+	// assert equal up to the last 24 bytes of random
+	assert.Equal(t, expect[:len(expect)-24], body[:len(body)-24])
+}

connection.go

@@ -3,12 +3,10 @@ package pearl
 import (
 	"crypto/sha256"
 	"encoding/hex"
-	"fmt"
 	"hash"
 	"io"
 	"net"
 
-	"github.com/mmcloughlin/pearl/debug"
 	"github.com/mmcloughlin/pearl/tls"
 	"github.com/mmcloughlin/pearl/torcrypto"
 
@@ -247,8 +245,6 @@ func (c *Connection) clientHandshake() error {
 		return errors.New("missing server link cert")
 	}
 
-	debug.DumpBytes("server_link", serverLinkCert)
-
 	serverIDCertDER := peerCertsCell.Lookup(CertTypeIdentity)
 	if serverIDCertDER == nil {
 		return errors.New("missing server identity cert")
@@ -261,10 +257,6 @@ func (c *Connection) clientHandshake() error {
 
 	cs := c.tlsConn.ConnectionState()
 
-	for i, crt := range cs.PeerCertificates {
-		debug.DumpBytes(fmt.Sprintf("peer_cert_%d", i), crt.Raw)
-	}
-
 	a := &AuthRSASHA256TLSSecret{
 		AuthKey:           c.tlsCtx.AuthKey,
 		ClientIdentityKey: &c.router.idKey.PublicKey,

debug/debug.go

@@ -2,12 +2,58 @@
 package debug
 
 import (
+	"bytes"
+	"crypto/rsa"
 	"encoding/hex"
 	"fmt"
 	"io/ioutil"
+	"os"
+	"path/filepath"
+
+	"github.com/mmcloughlin/pearl/torcrypto"
 )
 
 func DumpBytes(name string, data []byte) {
 	fmt.Print(hex.Dump(data))
-	ioutil.WriteFile(name, data, 0640)
+	ioutil.WriteFile(filename(name), data, 0640)
+}
+
+func DumpByteArray(name string, data []byte) {
+	f, err := os.Create(filename(name))
+	if err != nil {
+		panic(err)
+	}
+	defer f.Close()
+
+	fmt.Fprint(f, GoStringByteArray(data))
+}
+
+func GoStringByteArray(data []byte) string {
+	var buf bytes.Buffer
+	fmt.Fprint(&buf, "[]byte{")
+	for i, b := range data {
+		if i%16 == 0 {
+			fmt.Fprint(&buf, "\n\t")
+		}
+		fmt.Fprintf(&buf, "0x%02x, ", b)
+	}
+	fmt.Fprint(&buf, "\n}")
+	return string(buf.Bytes())
+}
+
+func GoStringRSAPrivateKey(k *rsa.PrivateKey) string {
+	pem := torcrypto.MarshalRSAPrivateKeyPKCS1PEM(k)
+	return fmt.Sprintf("torcrypto.MustRSAPrivateKey(torcrypto.ParseRSAPrivateKeyPKCS1PEM([]byte(%#v)))", string(pem))
+}
+
+func GoStringRSAPublicKey(k *rsa.PublicKey) string {
+	pem, err := torcrypto.MarshalRSAPublicKeyPKCS1PEM(k)
+	if err != nil {
+		panic(err)
+	}
+	return fmt.Sprintf("torcrypto.MustRSAPublicKey(torcrypto.ParseRSAPublicKeyPKCS1PEM([]byte(%#v)))", string(pem))
+}
+
+func filename(name string) string {
+	return filepath.Join("output", name)
 }

hashio.go

@@ -2,20 +2,23 @@ package pearl
 
 import "hash"
 
+// HashedCellReader maintains a running digest of all cells it receives.
 type HashedCellReader struct {
 	r CellReader
 	h hash.Hash
 }
 
 var _ CellReader = new(HashedCellReader)
 
+// NewHashedCellReader reads cells from c and hashes them with h.
 func NewHashedCellReader(r CellReader, h hash.Hash) *HashedCellReader {
 	return &HashedCellReader{
 		r: r,
 		h: h,
 	}
 }
 
+// ReadCell reads a cell and hashes it.
 func (h *HashedCellReader) ReadCell(f CellFormat) (Cell, error) {
 	c, err := h.r.ReadCell(f)
 	if err != nil {
@@ -29,7 +32,3 @@ func (h *HashedCellReader) ReadCell(f CellFormat) (Cell, error) {
 
 	return c, nil
 }
-
-func (h *HashedCellReader) Sum(b []byte) []byte {
-	return h.h.Sum(b)
-}

torcrypto/enc.go

@@ -10,6 +10,20 @@ import (
 	"github.com/pkg/errors"
 )
 
+func MustRSAPrivateKey(k *rsa.PrivateKey, err error) *rsa.PrivateKey {
+	if err != nil {
+		panic(err)
+	}
+	return k
+}
+
+func MustRSAPublicKey(k *rsa.PublicKey, err error) *rsa.PublicKey {
+	if err != nil {
+		panic(err)
+	}
+	return k
+}
+
 // MarshalRSAPrivateKeyPKCS1DER encodes k as PKCS#1 DER.
 func MarshalRSAPrivateKeyPKCS1DER(k *rsa.PrivateKey) []byte {
 	return x509.MarshalPKCS1PrivateKey(k)

torcrypto/rsa.go

@@ -68,6 +68,19 @@ func publicKeyHash(k *rsa.PublicKey, h hash.Hash) ([]byte, error) {
 // SignRSASHA1 signs data with k. This is the RSA encryption of the SHA-1 hash
 // of data, with PKCS#1 v1.5 padding.
 func SignRSASHA1(data []byte, k *rsa.PrivateKey) ([]byte, error) {
-	digest := sha1.Sum(data)
-	return rsa.SignPKCS1v15(nil, k, 0, digest[:])
+	return signRSA(data, k, sha1.New())
+}
+
+// SignRSASHA256 signs data with k. This is the RSA encryption of the SHA-256
+// hash of data, with PKCS#1 v1.5 padding.
+func SignRSASHA256(data []byte, k *rsa.PrivateKey) ([]byte, error) {
+	return signRSA(data, k, sha256.New())
+}
+
+func signRSA(data []byte, k *rsa.PrivateKey, h hash.Hash) ([]byte, error) {
+	_, err := h.Write(data)
+	if err != nil {
+		return nil, err
+	}
+	return rsa.SignPKCS1v15(nil, k, 0, h.Sum(nil))
 }