mirror of
https://github.com/fumiama/WireGold.git
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124 lines
3.1 KiB
Go
124 lines
3.1 KiB
Go
package link
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import (
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"crypto/rand"
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"encoding/binary"
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)
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// Encode 使用 TEA 加密
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func (l *Link) Encode(teatype uint8, b []byte) (eb []byte) {
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if b == nil || teatype >= 16 {
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return
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}
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if l.key == nil {
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eb = b
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return
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}
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// 在此处填写加密逻辑，密钥是l.key，输入是b，输出是eb
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// 不用写return，直接赋值给eb即可
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eb = l.key[teatype].Encrypt(b)
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return
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}
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// Decode 使用 TEA 解密
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func (l *Link) Decode(teatype uint8, b []byte) (db []byte) {
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if b == nil || teatype >= 16 {
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return
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}
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if l.key == nil {
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db = b
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return
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}
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// 在此处填写解密逻辑，密钥是l.key，输入是b，输出是db
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// 不用写return，直接赋值给db即可
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db = l.key[teatype].Decrypt(b)
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return
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}
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// EncodePreshared 使用 xchacha20poly1305 加密
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func (l *Link) EncodePreshared(additional uint16, b []byte) (eb []byte) {
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nsz := l.aead.NonceSize()
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// Select a random nonce, and leave capacity for the ciphertext.
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nonce := make([]byte, nsz, nsz+len(b)+l.aead.Overhead())
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_, err := rand.Read(nonce)
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if err != nil {
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return
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}
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// Encrypt the message and append the ciphertext to the nonce.
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var buf [2]byte
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binary.LittleEndian.PutUint16(buf[:], additional)
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eb = l.aead.Seal(nonce, nonce, b, buf[:])
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return
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}
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// DecodePreshared 使用 xchacha20poly1305 解密
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func (l *Link) DecodePreshared(additional uint16, b []byte) (db []byte) {
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nsz := l.aead.NonceSize()
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if len(b) < nsz { // ciphertext too short
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return
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}
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// Split nonce and ciphertext.
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nonce, ciphertext := b[:nsz], b[nsz:]
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// Decrypt the message and check it wasn't tampered with.
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var buf [2]byte
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binary.LittleEndian.PutUint16(buf[:], additional)
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db, _ = l.aead.Open(nil, nonce, ciphertext, buf[:])
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return
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}
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// xorenc 按 8 字节, 以初始 m.mask 循环异或编码 data
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func (m *Me) xorenc(data []byte) []byte {
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batchsz := len(data) / 8
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remain := len(data) % 8
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sum := m.mask
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if remain > 0 {
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var buf [8]byte
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p := batchsz * 8
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copy(buf[:], data[p:])
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sum ^= binary.LittleEndian.Uint64(buf[:])
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binary.LittleEndian.PutUint64(buf[:], sum)
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copy(data[p:], buf[:])
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}
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for i := batchsz - 1; i >= 0; i-- {
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a := i * 8
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b := (i + 1) * 8
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sum ^= binary.LittleEndian.Uint64(data[a:b])
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binary.LittleEndian.PutUint64(data[a:b], sum)
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}
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return data
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}
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// xordec 按 8 字节, 以初始 m.mask 循环异或解码 data
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func (m *Me) xordec(data []byte) []byte {
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batchsz := len(data) / 8
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remain := len(data) % 8
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this := uint64(0)
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next := uint64(0)
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if len(data) >= 8 {
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next = binary.LittleEndian.Uint64(data[:8])
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}
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for i := 0; i < batchsz-1; i++ {
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a := i * 8
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b := (i + 1) * 8
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this = next
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next = binary.LittleEndian.Uint64(data[a+8 : b+8])
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binary.LittleEndian.PutUint64(data[a:b], this^next)
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}
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if remain > 0 {
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var buf [8]byte
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a := (batchsz - 1) * 8
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b := batchsz * 8
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copy(buf[:], data[b:])
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this = next
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next = binary.LittleEndian.Uint64(buf[:]) | (m.mask & (uint64(0xffffffff_ffffffff) << (uint64(remain) * 8)))
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if batchsz > 0 {
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binary.LittleEndian.PutUint64(data[a:b], this^next)
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}
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binary.LittleEndian.PutUint64(buf[:], next^m.mask)
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copy(data[b:], buf[:])
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} else {
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binary.LittleEndian.PutUint64(data[len(data)-8:], next^m.mask)
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}
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return data
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}
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