59 lines
1.6 KiB
Go
59 lines
1.6 KiB
Go
package crypto
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import (
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"crypto/cipher"
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"errors"
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"github.com/lucas-clemente/aes12"
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"github.com/lucas-clemente/quic-go/protocol"
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)
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type aeadAESGCM 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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// NewAEADAESGCM creates a AEAD using AES-GCM with 12 bytes tag size
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//
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// AES-GCM support is a bit hacky, since the go stdlib does not support 12 byte
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// tag size, and couples the cipher and aes packages closely.
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// See https://github.com/lucas-clemente/aes12.
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func NewAEADAESGCM(otherKey []byte, myKey []byte, otherIV []byte, myIV []byte) (AEAD, error) {
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if len(myKey) != 16 || len(otherKey) != 16 || len(myIV) != 4 || len(otherIV) != 4 {
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return nil, errors.New("AES-GCM: expected 16-byte keys and 4-byte IVs")
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}
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encrypterCipher, err := aes12.NewCipher(myKey)
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if err != nil {
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return nil, err
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}
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encrypter, err := aes12.NewGCM(encrypterCipher)
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if err != nil {
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return nil, err
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}
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decrypterCipher, err := aes12.NewCipher(otherKey)
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if err != nil {
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return nil, err
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}
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decrypter, err := aes12.NewGCM(decrypterCipher)
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if err != nil {
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return nil, err
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}
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return &aeadAESGCM{
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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 *aeadAESGCM) Open(dst, src []byte, packetNumber protocol.PacketNumber, associatedData []byte) ([]byte, error) {
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return aead.decrypter.Open(dst, makeNonce(aead.otherIV, packetNumber), src, associatedData)
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}
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func (aead *aeadAESGCM) Seal(dst, src []byte, packetNumber protocol.PacketNumber, associatedData []byte) []byte {
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return aead.encrypter.Seal(dst, makeNonce(aead.myIV, packetNumber), src, associatedData)
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}
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