mirror of https://gogs.blitter.com/RLabs/xs
117 lines
3.1 KiB
Go
117 lines
3.1 KiB
Go
/* Herradura - a Key exchange scheme in the style of Diffie-Hellman Key Exchange.
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Copyright (C) 2017 Omar Alejandro Herrera Reyna
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This program is free software: you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation, either version 3 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program. If not, see <https://www.gnu.org/licenses/>.
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golang implementation by Russ Magee (rmagee_at_gmail.com) */
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package herradurakex
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/* Support functions to set up encryption once an HKEx Conn has been
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established with FA exchange */
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import (
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"crypto/aes"
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"crypto/cipher"
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"fmt"
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"io"
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"math/big"
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"os"
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)
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const (
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C_AES_256 = 0
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)
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const (
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H_SHA256 = 0
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)
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/*TODO: HMAC derived from HKEx FA.*/
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/* Support functionality to set up encryption after a channel has
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been negotiated via hkexnet.go
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*/
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func (hc Conn) getStreamReader(keymat *big.Int, flags uint32, r io.Reader) (ret *cipher.StreamReader) {
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var key []byte
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var block cipher.Block
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var err error
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// 256 algs should be enough for everybody.(tm)
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cipherAlg := (flags & 8)
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//TODO: flags for HMAC from keymat
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switch cipherAlg {
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case C_AES_256:
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key = keymat.Bytes()[0:aes.BlockSize]
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block, err = aes.NewCipher(key)
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break
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default:
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fmt.Println("DOOFUS SET A VALID CIPHER ALG")
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block, err = aes.NewCipher(key)
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os.Exit(1)
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}
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if err != nil {
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panic(err)
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}
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// If the key is unique for each ciphertext, then it's ok to use a zero
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// IV.
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var iv [aes.BlockSize]byte
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stream := cipher.NewOFB(block, iv[:])
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ret = &cipher.StreamReader{S: stream, R: r}
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// Note that this example is simplistic in that it omits any
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// authentication of the encrypted data. If you were actually to use
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// StreamReader in this manner, an attacker could flip arbitrary bits in
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// the output.
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return
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}
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func (hc Conn) getStreamWriter(keymat *big.Int, flags uint32, w io.Writer) (ret *cipher.StreamWriter) {
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var key []byte
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var block cipher.Block
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var err error
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// 256 algs should be enough for everybody.(tm)
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cipherAlg := (flags & 8)
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//TODO: flags for HMAC from keymat
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switch cipherAlg {
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case C_AES_256:
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key = keymat.Bytes()[0:aes.BlockSize]
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block, err = aes.NewCipher(key)
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break
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default:
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fmt.Println("DOOFUS SET A VALID CIPHER ALG")
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block, err = aes.NewCipher(key)
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os.Exit(1)
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}
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if err != nil {
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panic(err)
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}
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// If the key is unique for each ciphertext, then it's ok to use a zero
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// IV.
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var iv [aes.BlockSize]byte
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stream := cipher.NewOFB(block, iv[:])
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ret = &cipher.StreamWriter{S: stream, W: w}
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// Note that this example is simplistic in that it omits any
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// authentication of the encrypted data. If you were actually to use
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// StreamReader in this manner, an attacker could flip arbitrary bits in
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// the output.
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return
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}
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