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authorupstream source tree <ports@midipix.org>2015-03-15 20:14:05 -0400
committerupstream source tree <ports@midipix.org>2015-03-15 20:14:05 -0400
commit554fd8c5195424bdbcabf5de30fdc183aba391bd (patch)
tree976dc5ab7fddf506dadce60ae936f43f58787092 /libgo/go/crypto/openpgp/s2k/s2k.go
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Diffstat (limited to 'libgo/go/crypto/openpgp/s2k/s2k.go')
-rw-r--r--libgo/go/crypto/openpgp/s2k/s2k.go146
1 files changed, 146 insertions, 0 deletions
diff --git a/libgo/go/crypto/openpgp/s2k/s2k.go b/libgo/go/crypto/openpgp/s2k/s2k.go
new file mode 100644
index 000000000..f369d7ed4
--- /dev/null
+++ b/libgo/go/crypto/openpgp/s2k/s2k.go
@@ -0,0 +1,146 @@
+// 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.
+
+// This package implements the various OpenPGP string-to-key transforms as
+// specified in RFC 4800 section 3.7.1.
+package s2k
+
+import (
+ "crypto/md5"
+ "crypto/openpgp/error"
+ "crypto/ripemd160"
+ "crypto/sha1"
+ "crypto/sha256"
+ "crypto/sha512"
+ "hash"
+ "io"
+ "os"
+)
+
+// Simple writes to out the result of computing the Simple S2K function (RFC
+// 4880, section 3.7.1.1) using the given hash and input passphrase.
+func Simple(out []byte, h hash.Hash, in []byte) {
+ Salted(out, h, in, nil)
+}
+
+var zero [1]byte
+
+// Salted writes to out the result of computing the Salted S2K function (RFC
+// 4880, section 3.7.1.2) using the given hash, input passphrase and salt.
+func Salted(out []byte, h hash.Hash, in []byte, salt []byte) {
+ done := 0
+
+ for i := 0; done < len(out); i++ {
+ h.Reset()
+ for j := 0; j < i; j++ {
+ h.Write(zero[:])
+ }
+ h.Write(salt)
+ h.Write(in)
+ n := copy(out[done:], h.Sum())
+ done += n
+ }
+}
+
+// Iterated writes to out the result of computing the Iterated and Salted S2K
+// function (RFC 4880, section 3.7.1.3) using the given hash, input passphrase,
+// salt and iteration count.
+func Iterated(out []byte, h hash.Hash, in []byte, salt []byte, count int) {
+ combined := make([]byte, len(in)+len(salt))
+ copy(combined, salt)
+ copy(combined[len(salt):], in)
+
+ if count < len(combined) {
+ count = len(combined)
+ }
+
+ done := 0
+ for i := 0; done < len(out); i++ {
+ h.Reset()
+ for j := 0; j < i; j++ {
+ h.Write(zero[:])
+ }
+ written := 0
+ for written < count {
+ if written+len(combined) > count {
+ todo := count - written
+ h.Write(combined[:todo])
+ written = count
+ } else {
+ h.Write(combined)
+ written += len(combined)
+ }
+ }
+ n := copy(out[done:], h.Sum())
+ done += n
+ }
+}
+
+// Parse reads a binary specification for a string-to-key transformation from r
+// and returns a function which performs that transform.
+func Parse(r io.Reader) (f func(out, in []byte), err os.Error) {
+ var buf [9]byte
+
+ _, err = io.ReadFull(r, buf[:2])
+ if err != nil {
+ return
+ }
+
+ h := hashFuncFromType(buf[1])
+ if h == nil {
+ return nil, error.UnsupportedError("hash for S2K function")
+ }
+
+ switch buf[0] {
+ case 1:
+ f := func(out, in []byte) {
+ Simple(out, h, in)
+ }
+ return f, nil
+ case 2:
+ _, err := io.ReadFull(r, buf[:8])
+ if err != nil {
+ return
+ }
+ f := func(out, in []byte) {
+ Salted(out, h, in, buf[:8])
+ }
+ return f, nil
+ case 3:
+ _, err := io.ReadFull(r, buf[:9])
+ if err != nil {
+ return
+ }
+ count := (16 + int(buf[8]&15)) << (uint32(buf[8]>>4) + 6)
+ f := func(out, in []byte) {
+ Iterated(out, h, in, buf[:8], count)
+ }
+ return f, nil
+ }
+
+ return nil, error.UnsupportedError("S2K function")
+}
+
+// hashFuncFromType returns a hash.Hash which corresponds to the given hash
+// type byte. See RFC 4880, section 9.4.
+func hashFuncFromType(hashType byte) hash.Hash {
+ switch hashType {
+ case 1:
+ return md5.New()
+ case 2:
+ return sha1.New()
+ case 3:
+ return ripemd160.New()
+ case 8:
+ return sha256.New()
+ case 9:
+ return sha512.New384()
+ case 10:
+ return sha512.New()
+ case 11:
+ return sha256.New224()
+ }
+
+ return nil
+}