62 lines
1.8 KiB
Go
62 lines
1.8 KiB
Go
// +build ignore
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package crypto
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import (
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"crypto/cipher"
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"encoding/binary"
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"errors"
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"github.com/aead/chacha20"
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"github.com/lucas-clemente/quic-go/internal/protocol"
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)
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type aeadChacha20Poly1305 struct {
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otherIV []byte
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myIV []byte
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encrypter cipher.AEAD
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decrypter cipher.AEAD
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}
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// NewAEADChacha20Poly1305 creates a AEAD using chacha20poly1305
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func NewAEADChacha20Poly1305(otherKey []byte, myKey []byte, otherIV []byte, myIV []byte) (AEAD, error) {
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if len(myKey) != 32 || len(otherKey) != 32 || len(myIV) != 4 || len(otherIV) != 4 {
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return nil, errors.New("chacha20poly1305: expected 32-byte keys and 4-byte IVs")
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}
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// copy because ChaCha20Poly1305 expects array pointers
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var MyKey, OtherKey [32]byte
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copy(MyKey[:], myKey)
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copy(OtherKey[:], otherKey)
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encrypter, err := chacha20.NewChaCha20Poly1305WithTagSize(&MyKey, 12)
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if err != nil {
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return nil, err
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}
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decrypter, err := chacha20.NewChaCha20Poly1305WithTagSize(&OtherKey, 12)
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if err != nil {
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return nil, err
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}
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return &aeadChacha20Poly1305{
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otherIV: otherIV,
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myIV: myIV,
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encrypter: encrypter,
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decrypter: decrypter,
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}, nil
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}
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func (aead *aeadChacha20Poly1305) Open(dst, src []byte, packetNumber protocol.PacketNumber, associatedData []byte) ([]byte, error) {
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return aead.decrypter.Open(dst, aead.makeNonce(aead.otherIV, packetNumber), src, associatedData)
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}
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func (aead *aeadChacha20Poly1305) Seal(dst, src []byte, packetNumber protocol.PacketNumber, associatedData []byte) []byte {
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return aead.encrypter.Seal(dst, aead.makeNonce(aead.myIV, packetNumber), src, associatedData)
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}
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func (aead *aeadChacha20Poly1305) makeNonce(iv []byte, packetNumber protocol.PacketNumber) []byte {
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res := make([]byte, 12)
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copy(res[0:4], iv)
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binary.LittleEndian.PutUint64(res[4:12], uint64(packetNumber))
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return res
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}
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