47 lines
1.3 KiB
Go
47 lines
1.3 KiB
Go
package chachapoly
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import (
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"crypto/rand"
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"fmt"
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"io"
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"golang.org/x/crypto/chacha20poly1305"
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)
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// Encrypt encrypts data using ChaCha20-Poly1305.
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func Encrypt(plaintext []byte, key []byte) ([]byte, error) {
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if len(key) != chacha20poly1305.KeySize {
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return nil, fmt.Errorf("invalid key size: got %d bytes, want %d bytes", len(key), chacha20poly1305.KeySize)
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}
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aead, err := chacha20poly1305.NewX(key)
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if err != nil {
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return nil, err
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}
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nonce := make([]byte, aead.NonceSize(), aead.NonceSize()+len(plaintext)+aead.Overhead())
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if _, err := io.ReadFull(rand.Reader, nonce); err != nil {
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return nil, err
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}
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return aead.Seal(nonce, nonce, plaintext, nil), nil
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}
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// Decrypt decrypts data using ChaCha20-Poly1305.
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func Decrypt(ciphertext []byte, key []byte) ([]byte, error) {
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if len(key) != chacha20poly1305.KeySize {
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return nil, fmt.Errorf("invalid key size: got %d bytes, want %d bytes", len(key), chacha20poly1305.KeySize)
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}
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aead, err := chacha20poly1305.NewX(key)
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if err != nil {
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return nil, err
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}
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minLen := aead.NonceSize() + aead.Overhead()
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if len(ciphertext) < minLen {
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return nil, fmt.Errorf("ciphertext too short: got %d bytes, need at least %d bytes", len(ciphertext), minLen)
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}
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nonce, ciphertext := ciphertext[:aead.NonceSize()], ciphertext[aead.NonceSize():]
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return aead.Open(nil, nonce, ciphertext, nil)
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}
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