58 lines
2.2 KiB
Go
58 lines
2.2 KiB
Go
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// Copyright 2017-2021 DERO Project. All rights reserved.
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// Use of this source code in any form is governed by RESEARCH license.
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// license can be found in the LICENSE file.
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// GPG: 0F39 E425 8C65 3947 702A 8234 08B2 0360 A03A 9DE8
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//
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//
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// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY
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// EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
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// MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL
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// THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
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// PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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// INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
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// STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF
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// THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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package crypto
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import "math/big"
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import "golang.org/x/crypto/chacha20"
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import "github.com/deroproject/derohe/cryptography/bn256"
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import "github.com/go-logr/logr"
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var Logger logr.Logger = logr.Discard() // default discard all logs, someone needs to set this up
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// this function is used to encrypt/decrypt payment id,srcid and other userdata
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// as the operation is symmetric XOR, is the same in both direction
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//
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func EncryptDecryptUserData(key [32]byte, inputs ...[]byte) {
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var nonce [24]byte // nonce is 24 bytes, we will use xchacha20
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cipher, err := chacha20.NewUnauthenticatedCipher(key[:], nonce[:])
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if err != nil {
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panic(err)
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}
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for _, input := range inputs {
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cipher.XORKeyStream(input, input)
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}
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return
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}
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// does an ECDH and generates a shared secret
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// https://en.wikipedia.org/wiki/Elliptic_curve_Diffie%E2%80%93Hellman
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func GenerateSharedSecret(secret *big.Int, peer_publickey *bn256.G1) (shared_key [32]byte) {
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shared_point := new(bn256.G1).ScalarMult(peer_publickey, secret)
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compressed := shared_point.EncodeCompressed()
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if len(compressed) != 33 {
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panic("point compression needs to be fixed")
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}
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shared_key = Keccak256(compressed[:])
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return
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}
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