62 lines
1.2 KiB
Go
62 lines
1.2 KiB
Go
package peer
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import (
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"crypto/aes"
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"crypto/cipher"
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"crypto/rand"
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"log"
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)
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type dataCipher struct {
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key [32]byte
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aead cipher.AEAD
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}
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func newDataCipher() *dataCipher {
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key := [32]byte{}
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if _, err := rand.Read(key[:]); err != nil {
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log.Fatalf("Failed to read random data: %v", err)
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}
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return newDataCipherFromKey(key)
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}
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func newDataCipherFromKey(key [32]byte) *dataCipher {
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block, err := aes.NewCipher(key[:])
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if err != nil {
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log.Fatalf("Failed to create new cipher: %v", err)
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}
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aead, err := cipher.NewGCM(block)
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if err != nil {
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log.Fatalf("Failed to create new GCM: %v", err)
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}
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return &dataCipher{key: key, aead: aead}
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}
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func (sc *dataCipher) Key() [32]byte {
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return sc.key
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}
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func (sc *dataCipher) Encrypt(h Header, data, out []byte) []byte {
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const s = dataHeaderSize
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out = out[:s+dataCipherOverhead+len(data)]
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h.Marshal(out[:s])
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sc.aead.Seal(out[s:s], out[:s], data, nil)
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return out
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}
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func (sc *dataCipher) Decrypt(encrypted, out []byte) (data []byte, ok bool) {
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const s = dataHeaderSize
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if len(encrypted) < s+dataCipherOverhead {
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ok = false
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return
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}
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var err error
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data, err = sc.aead.Open(out[:0], encrypted[:s], encrypted[s:], nil)
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ok = err == nil
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return
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}
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