65 lines
1.7 KiB
Go
65 lines
1.7 KiB
Go
// Copyright 2010 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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package tls
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import (
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"crypto/aes"
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"crypto/cipher"
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"crypto/hmac"
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"crypto/rc4"
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"hash"
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)
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// A cipherSuite is a specific combination of key agreement, cipher and MAC
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// function. All cipher suites currently assume RSA key agreement.
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type cipherSuite struct {
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// the lengths, in bytes, of the key material needed for each component.
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keyLen int
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macLen int
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ivLen int
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cipher func(key, iv []byte, isRead bool) interface{}
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mac func(macKey []byte) hash.Hash
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}
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var cipherSuites = map[uint16]*cipherSuite{
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TLS_RSA_WITH_RC4_128_SHA: &cipherSuite{16, 20, 0, cipherRC4, hmacSHA1},
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TLS_RSA_WITH_AES_128_CBC_SHA: &cipherSuite{16, 20, 16, cipherAES, hmacSHA1},
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}
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func cipherRC4(key, iv []byte, isRead bool) interface{} {
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cipher, _ := rc4.NewCipher(key)
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return cipher
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}
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func cipherAES(key, iv []byte, isRead bool) interface{} {
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block, _ := aes.NewCipher(key)
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if isRead {
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return cipher.NewCBCDecrypter(block, iv)
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}
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return cipher.NewCBCEncrypter(block, iv)
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}
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func hmacSHA1(key []byte) hash.Hash {
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return hmac.NewSHA1(key)
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}
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// mutualCipherSuite returns a cipherSuite and its id given a list of supported
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// ciphersuites and the id requested by the peer.
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func mutualCipherSuite(have []uint16, want uint16) (suite *cipherSuite, id uint16) {
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for _, id := range have {
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if id == want {
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return cipherSuites[id], id
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}
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}
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return
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}
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// A list of the possible cipher suite ids. Taken from
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// http://www.iana.org/assignments/tls-parameters/tls-parameters.xml
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const (
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TLS_RSA_WITH_RC4_128_SHA uint16 = 0x0005
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TLS_RSA_WITH_AES_128_CBC_SHA uint16 = 0x002f
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)
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