45 lines
1.5 KiB
Go
45 lines
1.5 KiB
Go
package crypto
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import (
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"crypto"
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"encoding/binary"
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"github.com/bifurcation/mint"
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"github.com/lucas-clemente/quic-go/internal/protocol"
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)
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var quicVersion1Salt = []byte{0xaf, 0xc8, 0x24, 0xec, 0x5f, 0xc7, 0x7e, 0xca, 0x1e, 0x9d, 0x36, 0xf3, 0x7f, 0xb2, 0xd4, 0x65, 0x18, 0xc3, 0x66, 0x39}
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func newNullAEADAESGCM(connectionID protocol.ConnectionID, pers protocol.Perspective) (AEAD, error) {
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clientSecret, serverSecret := computeSecrets(connectionID)
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var mySecret, otherSecret []byte
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if pers == protocol.PerspectiveClient {
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mySecret = clientSecret
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otherSecret = serverSecret
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} else {
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mySecret = serverSecret
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otherSecret = clientSecret
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}
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myKey, myIV := computeNullAEADKeyAndIV(mySecret)
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otherKey, otherIV := computeNullAEADKeyAndIV(otherSecret)
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return NewAEADAESGCM(otherKey, myKey, otherIV, myIV)
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}
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func computeSecrets(connectionID protocol.ConnectionID) (clientSecret, serverSecret []byte) {
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connID := make([]byte, 8)
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binary.BigEndian.PutUint64(connID, uint64(connectionID))
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cleartextSecret := mint.HkdfExtract(crypto.SHA256, []byte(quicVersion1Salt), connID)
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clientSecret = mint.HkdfExpandLabel(crypto.SHA256, cleartextSecret, "QUIC client cleartext Secret", []byte{}, crypto.SHA256.Size())
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serverSecret = mint.HkdfExpandLabel(crypto.SHA256, cleartextSecret, "QUIC server cleartext Secret", []byte{}, crypto.SHA256.Size())
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return
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}
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func computeNullAEADKeyAndIV(secret []byte) (key, iv []byte) {
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key = mint.HkdfExpandLabel(crypto.SHA256, secret, "key", nil, 16)
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iv = mint.HkdfExpandLabel(crypto.SHA256, secret, "iv", nil, 12)
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return
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}
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