mirror of https://gogs.blitter.com/RLabs/xs
53 lines
1003 B
Go
53 lines
1003 B
Go
package kcp
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import (
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"crypto/aes"
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"crypto/cipher"
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"crypto/md5"
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"crypto/rand"
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"io"
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)
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// Entropy defines a entropy source
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type Entropy interface {
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Init()
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Fill(nonce []byte)
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}
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// nonceMD5 nonce generator for packet header
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type nonceMD5 struct {
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seed [md5.Size]byte
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}
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func (n *nonceMD5) Init() { /*nothing required*/ }
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func (n *nonceMD5) Fill(nonce []byte) {
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if n.seed[0] == 0 { // entropy update
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io.ReadFull(rand.Reader, n.seed[:])
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}
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n.seed = md5.Sum(n.seed[:])
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copy(nonce, n.seed[:])
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}
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// nonceAES128 nonce generator for packet headers
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type nonceAES128 struct {
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seed [aes.BlockSize]byte
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block cipher.Block
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}
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func (n *nonceAES128) Init() {
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var key [16]byte //aes-128
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io.ReadFull(rand.Reader, key[:])
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io.ReadFull(rand.Reader, n.seed[:])
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block, _ := aes.NewCipher(key[:])
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n.block = block
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}
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func (n *nonceAES128) Fill(nonce []byte) {
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if n.seed[0] == 0 { // entropy update
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io.ReadFull(rand.Reader, n.seed[:])
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}
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n.block.Encrypt(n.seed[:], n.seed[:])
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copy(nonce, n.seed[:])
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}
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