43 lines
1.1 KiB
Go
43 lines
1.1 KiB
Go
package crypto
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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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"io"
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)
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func EncryptRecord(plaintext []byte, key [32]byte) (nonce [12]byte, ciphertext []byte, authTag []byte, err error) {
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block, err := aes.NewCipher(key[:])
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if err != nil {
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return nonce, nil, nil, 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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return nonce, nil, nil, err
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}
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_, err = io.ReadFull(rand.Reader, nonce[:])
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if err != nil {
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return nonce, nil, nil, err
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}
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sealed := aead.Seal(nil, nonce[:], plaintext, nil)
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tagStart := len(sealed) - aead.Overhead()
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ciphertext = sealed[:tagStart]
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authTag = sealed[tagStart:]
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return nonce, ciphertext, authTag, nil
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}
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func DecryptRecord(ciphertext []byte, nonce [12]byte, authTag []byte, key [32]byte) ([]byte, error) {
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block, err := aes.NewCipher(key[:])
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if err != nil {
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return nil, 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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return nil, err
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}
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sealed := make([]byte, len(ciphertext)+len(authTag))
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copy(sealed, ciphertext)
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copy(sealed[len(ciphertext):], authTag)
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return aead.Open(nil, nonce[:], sealed, nil)
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}
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