70 lines
1.9 KiB
Go
70 lines
1.9 KiB
Go
package v1
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import (
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"crypto/rand"
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"errors"
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"git.openprivacy.ca/openprivacy/log"
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"golang.org/x/crypto/nacl/secretbox"
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"golang.org/x/crypto/pbkdf2"
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"golang.org/x/crypto/sha3"
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"io"
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"os"
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path "path/filepath"
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)
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// CreateKeySalt derives a key and salt from a password: returns key, salt, err
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func CreateKeySalt(password string) ([32]byte, [128]byte, error) {
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var salt [128]byte
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if _, err := io.ReadFull(rand.Reader, salt[:]); err != nil {
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log.Errorf("Cannot read from random: %v\n", err)
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return [32]byte{}, salt, err
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}
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dk := pbkdf2.Key([]byte(password), salt[:], 4096, 32, sha3.New512)
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var dkr [32]byte
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copy(dkr[:], dk)
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return dkr, salt, nil
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}
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// CreateKey derives a key from a password and salt
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func CreateKey(password string, salt []byte) [32]byte {
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dk := pbkdf2.Key([]byte(password), salt, 4096, 32, sha3.New512)
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var dkr [32]byte
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copy(dkr[:], dk)
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return dkr
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}
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// EncryptFileData encrypts the data with the supplied key
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func EncryptFileData(data []byte, key [32]byte) ([]byte, error) {
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var nonce [24]byte
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if _, err := io.ReadFull(rand.Reader, nonce[:]); err != nil {
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log.Errorf("Cannot read from random: %v\n", err)
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return nil, err
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}
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encrypted := secretbox.Seal(nonce[:], data, &nonce, &key)
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return encrypted, nil
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}
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// DecryptFile decrypts the passed ciphertext with the supplied key.
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func DecryptFile(ciphertext []byte, key [32]byte) ([]byte, error) {
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var decryptNonce [24]byte
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copy(decryptNonce[:], ciphertext[:24])
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decrypted, ok := secretbox.Open(nil, ciphertext[24:], &decryptNonce, &key)
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if ok {
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return decrypted, nil
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}
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return nil, errors.New("failed to decrypt")
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}
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// ReadEncryptedFile reads data from an encrypted file in directory with key
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func ReadEncryptedFile(directory, filename string, key [32]byte) ([]byte, error) {
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encryptedbytes, err := os.ReadFile(path.Join(directory, filename))
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if err == nil {
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return DecryptFile(encryptedbytes, key)
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}
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return nil, err
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}
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