crypto/block.install: fmt.install io.install os.install strconv.install
crypto/hmac.install: crypto/md5.install crypto/sha1.install hash.install os.install
crypto/md5.install: hash.install os.install
+crypto/rc4.install: os.install strconv.install
crypto/sha1.install: hash.install os.install
datafmt.install: bytes.install container/vector.install fmt.install go/scanner.install go/token.install io.install os.install reflect.install runtime.install strconv.install strings.install
debug/binary.install: io.install math.install os.install reflect.install
go/ast.install: go/token.install unicode.install utf8.install
go/doc.install: container/vector.install go/ast.install go/token.install io.install once.install regexp.install sort.install strings.install template.install
go/parser.install: bytes.install container/vector.install fmt.install go/ast.install go/scanner.install go/token.install io.install os.install path.install strings.install
-go/printer.install: bytes.install container/vector.install fmt.install go/ast.install go/token.install io.install os.install reflect.install strings.install tabwriter.install
+go/printer.install: bytes.install container/vector.install fmt.install go/ast.install go/token.install io.install os.install reflect.install runtime.install strings.install tabwriter.install
go/scanner.install: bytes.install container/vector.install fmt.install go/token.install io.install os.install sort.install strconv.install unicode.install utf8.install
go/token.install: fmt.install strconv.install
gob.install: bytes.install fmt.install io.install math.install os.install reflect.install sync.install
--- /dev/null
+// Copyright 2009 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.
+
+// This package implements RC4 encryption, as defined in Bruce Schneier's
+// Applied Cryptography.
+package rc4
+
+// BUG(agl): RC4 is in common use but has design weaknesses that make
+// it a poor choice for new protocols.
+
+import (
+ "os";
+ "strconv";
+)
+
+// A Cipher is an instance of RC4 using a particular key.
+type Cipher struct {
+ s [256]byte;
+ i, j uint8;
+}
+
+type KeySizeError int
+
+func (k KeySizeError) String() string {
+ return "crypto/rc4: invalid key size " + strconv.Itoa(int(k));
+}
+
+// NewCipher creates and returns a new Cipher. The key argument should be the
+// RC4 key, at least 1 byte and at most 256 bytes.
+func NewCipher(key []byte) (*Cipher, os.Error) {
+ k := len(key);
+ if k < 1 || k > 256 {
+ return nil, KeySizeError(k);
+ }
+ var c Cipher;
+ for i := 0; i < 256; i++ {
+ c.s[i] = uint8(i);
+ }
+ var j uint8 = 0;
+ for i := 0; i < 256; i++ {
+ j += c.s[i] + key[i%k];
+ c.s[i], c.s[j] = c.s[j], c.s[i];
+ }
+ return &c, nil;
+}
+
+// XORKeyStream will XOR each byte of the given buffer with a byte of the
+// generated keystream.
+func (c *Cipher) XORKeyStream(buf []byte) {
+ for i := range buf {
+ c.i += 1;
+ c.j += c.s[c.i];
+ c.s[c.i], c.s[c.j] = c.s[c.j], c.s[c.i];
+ buf[i] ^= c.s[c.s[c.i] + c.s[c.j]];
+ }
+}
+
+// Reset zeros the key data so that it will no longer appear in the
+// process's memory.
+func (c *Cipher) Reset() {
+ for i := range c.s {
+ c.s[i] = 0;
+ }
+ c.i, c.j = 0, 0;
+}
--- /dev/null
+// Copyright 2009 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 rc4
+
+import (
+ "testing";
+)
+
+type rc4Test struct {
+ key, keystream []byte;
+}
+
+var golden = []rc4Test{
+ // Test vectors from the original cypherpunk posting of ARC4:
+ // http://groups.google.com/group/sci.crypt/msg/10a300c9d21afca0?pli=1
+ rc4Test{
+ []byte{0x01, 0x23, 0x45, 0x67, 0x89, 0xab, 0xcd, 0xef},
+ []byte{0x74, 0x94, 0xc2, 0xe7, 0x10, 0x4b, 0x08, 0x79},
+ },
+ rc4Test{
+ []byte{0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00},
+ []byte{0xde, 0x18, 0x89, 0x41, 0xa3, 0x37, 0x5d, 0x3a},
+ },
+ rc4Test{
+ []byte{0xef, 0x01, 0x23, 0x45},
+ []byte{0xd6, 0xa1, 0x41, 0xa7, 0xec, 0x3c, 0x38, 0xdf, 0xbd, 0x61},
+ },
+
+ // Test vectors from the Wikipedia page: http://en.wikipedia.org/wiki/RC4
+ rc4Test{
+ []byte{0x4b, 0x65, 0x79},
+ []byte{0xeb, 0x9f, 0x77, 0x81, 0xb7, 0x34, 0xca, 0x72, 0xa7, 0x19},
+ },
+ rc4Test{
+ []byte{0x57, 0x69, 0x6b, 0x69},
+ []byte{0x60, 0x44, 0xdb, 0x6d, 0x41, 0xb7},
+ },
+}
+
+func TestGolden(t *testing.T) {
+ for i := 0; i < len(golden); i++ {
+ g := golden[i];
+ c, err := NewCipher(g.key);
+ if err != nil {
+ t.Errorf("Failed to create cipher at golden index %d", i);
+ return;
+ }
+ keystream := make([]byte, len(g.keystream));
+ c.XORKeyStream(keystream);
+ for j, v := range keystream {
+ if g.keystream[j] != v {
+ t.Errorf("Failed at golden index %d", i);
+ break;
+ }
+ }
+ }
+}