66 lines
1.6 KiB
Go
66 lines
1.6 KiB
Go
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package symm
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import (
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"crypto/cipher"
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"errors"
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"io"
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"golang.org/x/crypto/chacha20"
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"golang.org/x/crypto/chacha20poly1305"
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)
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var ErrInvalidChaCha20NonceLength = errors.New("chacha20 nonce length must be 12 or 24 bytes")
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func EncryptChaCha20(data, key, nonce []byte) ([]byte, error) {
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stream, err := chacha20.NewUnauthenticatedCipher(key, nonce)
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if err != nil {
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return nil, err
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}
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out := make([]byte, len(data))
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stream.XORKeyStream(out, data)
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return out, nil
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}
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func DecryptChaCha20(src, key, nonce []byte) ([]byte, error) {
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return EncryptChaCha20(src, key, nonce)
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}
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func EncryptChaCha20Stream(dst io.Writer, src io.Reader, key, nonce []byte) error {
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stream, err := chacha20.NewUnauthenticatedCipher(key, nonce)
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if err != nil {
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return err
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}
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return xorStreamCopy(dst, src, stream)
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}
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func DecryptChaCha20Stream(dst io.Writer, src io.Reader, key, nonce []byte) error {
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return EncryptChaCha20Stream(dst, src, key, nonce)
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}
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func EncryptChaCha20Poly1305(plain, key, nonce, aad []byte) ([]byte, error) {
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aead, err := newChaCha20AEAD(key, nonce)
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if err != nil {
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return nil, err
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}
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return aead.Seal(nil, nonce, plain, aad), nil
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}
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func DecryptChaCha20Poly1305(ciphertext, key, nonce, aad []byte) ([]byte, error) {
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aead, err := newChaCha20AEAD(key, nonce)
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if err != nil {
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return nil, err
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}
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return aead.Open(nil, nonce, ciphertext, aad)
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}
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func newChaCha20AEAD(key, nonce []byte) (cipher.AEAD, error) {
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switch len(nonce) {
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case chacha20poly1305.NonceSize:
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return chacha20poly1305.New(key)
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case chacha20poly1305.NonceSizeX:
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return chacha20poly1305.NewX(key)
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default:
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return nil, ErrInvalidChaCha20NonceLength
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}
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}
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