50 lines
897 B
Go
50 lines
897 B
Go
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package noise
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import (
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"crypto/hmac"
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"hash"
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)
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func hkdf(h func() hash.Hash, outputs int, out1, out2, out3, chainingKey, inputKeyMaterial []byte) ([]byte, []byte, []byte) {
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if len(out1) > 0 {
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panic("len(out1) > 0")
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}
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if len(out2) > 0 {
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panic("len(out2) > 0")
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}
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if len(out3) > 0 {
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panic("len(out3) > 0")
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}
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if outputs > 3 {
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panic("outputs > 3")
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}
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tempMAC := hmac.New(h, chainingKey)
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tempMAC.Write(inputKeyMaterial)
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tempKey := tempMAC.Sum(out2)
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out1MAC := hmac.New(h, tempKey)
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out1MAC.Write([]byte{0x01})
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out1 = out1MAC.Sum(out1)
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if outputs == 1 {
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return out1, nil, nil
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}
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out2MAC := hmac.New(h, tempKey)
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out2MAC.Write(out1)
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out2MAC.Write([]byte{0x02})
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out2 = out2MAC.Sum(out2)
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if outputs == 2 {
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return out1, out2, nil
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}
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out3MAC := hmac.New(h, tempKey)
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out3MAC.Write(out2)
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out3MAC.Write([]byte{0x03})
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out3 = out3MAC.Sum(out3)
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return out1, out2, out3
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}
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