Google uses AI technology to translate content into your preferred language. AI translations can contain errors.

Saya ingin mengenkripsi file atau aliran data besar

Sebaiknya gunakan primitive Streaming AEAD dengan jenis kunci AES128_GCM_HKDF_1MB untuk sebagian besar kasus penggunaan enkripsi file.

Primitive Streaming Authenticated Encryption with Associated Data (Streaming AEAD) berguna untuk mengenkripsi aliran data langsung atau file besar yang tidak sesuai dengan memori. Mirip dengan AEAD, primitive ini simetris, menggunakan satu kunci untuk enkripsi dan dekripsi.

Contoh berikut akan membantu Anda memulai menggunakan primitive Streaming AEAD:

Go

import (
	"bytes"
	"fmt"
	"io"
	"log"
	"os"
	"path/filepath"

	"github.com/tink-crypto/tink-go/v2/insecurecleartextkeyset"
	"github.com/tink-crypto/tink-go/v2/keyset"
	"github.com/tink-crypto/tink-go/v2/streamingaead"
)

func Example() {
	// A keyset created with "tinkey create-keyset --key-template=AES256_CTR_HMAC_SHA256_1MB". Note
	// that this keyset has the secret key information in cleartext.
	jsonKeyset := `{
    "primaryKeyId": 1720777699,
    "key": [{
        "keyData": {
            "typeUrl": "type.googleapis.com/google.crypto.tink.AesCtrHmacStreamingKey",
            "keyMaterialType": "SYMMETRIC",
            "value": "Eg0IgCAQIBgDIgQIAxAgGiDtesd/4gCnQdTrh+AXodwpm2b6BFJkp043n+8mqx0YGw=="
        },
        "outputPrefixType": "RAW",
        "keyId": 1720777699,
        "status": "ENABLED"
    }]
	}`

	// Create a keyset handle from the cleartext keyset in the previous
	// step. The keyset handle provides abstract access to the underlying keyset to
	// limit the exposure of accessing the raw key material. WARNING: In practice,
	// it is unlikely you will want to use an insecurecleartextkeyset, as it implies
	// that your key material is passed in cleartext, which is a security risk.
	// Consider encrypting it with a remote key in Cloud KMS, AWS KMS or HashiCorp Vault.
	// See https://github.com/google/tink/blob/master/docs/GOLANG-HOWTO.md#storing-and-loading-existing-keysets.
	keysetHandle, err := insecurecleartextkeyset.Read(
		keyset.NewJSONReader(bytes.NewBufferString(jsonKeyset)))
	if err != nil {
		log.Fatal(err)
	}

	// Retrieve the StreamingAEAD primitive we want to use from the keyset handle.
	primitive, err := streamingaead.New(keysetHandle)
	if err != nil {
		log.Fatal(err)
	}

	// Create a file with the plaintext.
	dir, err := os.MkdirTemp("", "streamingaead")
	if err != nil {
		log.Fatal(err)
	}
	defer os.RemoveAll(dir)
	plaintextPath := filepath.Join(dir, "plaintext")
	if err := os.WriteFile(plaintextPath, []byte("this data needs to be encrypted"), 0666); err != nil {
		log.Fatal(err)
	}
	plaintextFile, err := os.Open(plaintextPath)
	if err != nil {
		log.Fatal(err)
	}

	// associatedData defines the context of the encryption. Here, we include the path of the
	// plaintext file.
	associatedData := []byte("associatedData for " + plaintextPath)

	// Encrypt the plaintext file and write the output to the ciphertext file. In this case the
	// primary key of the keyset will be used (which is also the only key in this example).
	ciphertextPath := filepath.Join(dir, "ciphertext")
	ciphertextFile, err := os.Create(ciphertextPath)
	if err != nil {
		log.Fatal(err)
	}
	w, err := primitive.NewEncryptingWriter(ciphertextFile, associatedData)
	if err != nil {
		log.Fatal(err)
	}
	if _, err := io.Copy(w, plaintextFile); err != nil {
		log.Fatal(err)
	}
	if err := w.Close(); err != nil {
		log.Fatal(err)
	}
	if err := ciphertextFile.Close(); err != nil {
		log.Fatal(err)
	}
	if err := plaintextFile.Close(); err != nil {
		log.Fatal(err)
	}

	// Decrypt the ciphertext file and write the output to the decrypted file. The
	// decryption finds the correct key in the keyset and decrypts the ciphertext.
	// If no key is found or decryption fails, it returns an error.
	ciphertextFile, err = os.Open(ciphertextPath)
	if err != nil {
		log.Fatal(err)
	}
	decryptedPath := filepath.Join(dir, "decrypted")
	decryptedFile, err := os.Create(decryptedPath)
	if err != nil {
		log.Fatal(err)
	}
	r, err := primitive.NewDecryptingReader(ciphertextFile, associatedData)
	if err != nil {
		log.Fatal(err)
	}
	if _, err := io.Copy(decryptedFile, r); err != nil {
		log.Fatal(err)
	}
	if err := decryptedFile.Close(); err != nil {
		log.Fatal(err)
	}
	if err := ciphertextFile.Close(); err != nil {
		log.Fatal(err)
	}

	// Print the content of the decrypted file.
	b, err := os.ReadFile(decryptedPath)
	if err != nil {
		log.Fatal(err)
	}
	fmt.Println(string(b))
	// Output: this data needs to be encrypted
}
streamingaead_test.go

Java

package streamingaead;

import static java.nio.charset.StandardCharsets.UTF_8;

import com.google.crypto.tink.InsecureSecretKeyAccess;
import com.google.crypto.tink.KeysetHandle;
import com.google.crypto.tink.RegistryConfiguration;
import com.google.crypto.tink.StreamingAead;
import com.google.crypto.tink.TinkJsonProtoKeysetFormat;
import com.google.crypto.tink.streamingaead.StreamingAeadConfig;
import java.io.IOException;
import java.nio.ByteBuffer;
import java.nio.channels.FileChannel;
import java.nio.channels.ReadableByteChannel;
import java.nio.channels.WritableByteChannel;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;
import java.nio.file.StandardOpenOption;
import java.security.GeneralSecurityException;

/**
 * A command-line utility for encrypting files with Streaming AEAD.
 *
 * <p>It loads cleartext keys from disk - this is not recommended!
 *
 * <p>It requires the following arguments:
 *
 * <ul>
 *   <li>mode: Can be "encrypt" or "decrypt" to encrypt/decrypt the input to the output.
 *   <li>key-file: Read the key material from this file.
 *   <li>input-file: Read the input from this file.
 *   <li>output-file: Write the result to this file.
 *   <li>[optional] associated-data: Associated data used for the encryption or decryption.
 */
public final class StreamingAeadExample {
  private static final String MODE_ENCRYPT = "encrypt";
  private static final String MODE_DECRYPT = "decrypt";
  private static final int BLOCK_SIZE_IN_BYTES = 8 * 1024;

  public static void main(String[] args) throws Exception {
    if (args.length != 4 && args.length != 5) {
      System.err.printf("Expected 4 or 5 parameters, got %d\n", args.length);
      System.err.println(
          "Usage: java StreamingAeadExample encrypt/decrypt key-file input-file output-file"
              + " [associated-data]");
      System.exit(1);
    }
    String mode = args[0];
    Path keyFile = Paths.get(args[1]);
    Path inputFile = Paths.get(args[2]);
    Path outputFile = Paths.get(args[3]);
    byte[] associatedData = new byte[0];
    if (args.length == 5) {
      associatedData = args[4].getBytes(UTF_8);
    }

    // Initialize Tink: register all Streaming AEAD key types with the Tink runtime
    StreamingAeadConfig.register();

    // Read the keyset into a KeysetHandle
    KeysetHandle handle =
        TinkJsonProtoKeysetFormat.parseKeyset(
            new String(Files.readAllBytes(keyFile), UTF_8), InsecureSecretKeyAccess.get());

    // Get the primitive
    StreamingAead streamingAead =
        handle.getPrimitive(RegistryConfiguration.get(), StreamingAead.class);

    // Use the primitive to encrypt/decrypt files
    if (mode.equals(MODE_ENCRYPT)) {
      encryptFile(streamingAead, inputFile, outputFile, associatedData);
    } else if (mode.equals(MODE_DECRYPT)) {
      decryptFile(streamingAead, inputFile, outputFile, associatedData);
    } else {
      System.err.println(
          "The first argument must be either "
              + MODE_ENCRYPT
              + " or "
              + MODE_DECRYPT
              + ", got: "
              + mode);
      System.exit(1);
    }
  }

  private static void encryptFile(
      StreamingAead streamingAead, Path inputFile, Path outputFile, byte[] associatedData)
      throws GeneralSecurityException, IOException {
    try (WritableByteChannel encryptingChannel =
            streamingAead.newEncryptingChannel(
                FileChannel.open(outputFile, StandardOpenOption.WRITE, StandardOpenOption.CREATE),
                associatedData);
        FileChannel inputChannel = FileChannel.open(inputFile, StandardOpenOption.READ)) {
      ByteBuffer byteBuffer = ByteBuffer.allocate(BLOCK_SIZE_IN_BYTES);
      while (true) {
        int read = inputChannel.read(byteBuffer);
        if (read <= 0) {
          return;
        }
        byteBuffer.flip();
        while (byteBuffer.hasRemaining()) {
          encryptingChannel.write(byteBuffer);
        }
        byteBuffer.clear();
      }
    }
  }

  private static void decryptFile(
      StreamingAead streamingAead, Path inputFile, Path outputFile, byte[] associatedData)
      throws GeneralSecurityException, IOException {
    try (ReadableByteChannel decryptingChannel =
            streamingAead.newDecryptingChannel(
                FileChannel.open(inputFile, StandardOpenOption.READ), associatedData);
        FileChannel outputChannel =
            FileChannel.open(outputFile, StandardOpenOption.WRITE, StandardOpenOption.CREATE)) {
      ByteBuffer byteBuffer = ByteBuffer.allocate(BLOCK_SIZE_IN_BYTES);
      while (true) {
        int read = decryptingChannel.read(byteBuffer);
        if (read <= 0) {
          return;
        }
        byteBuffer.flip();
        while (byteBuffer.hasRemaining()) {
          outputChannel.write(byteBuffer);
        }
        byteBuffer.clear();
      }
    }
  }

  private StreamingAeadExample() {}
}StreamingAeadExample.java

Python

"""A command-line utility for using streaming AEAD for a file.

It loads cleartext keys from disk - this is not recommended!

It requires 4 arguments (and one optional one):
  mode: either 'encrypt' or 'decrypt'
  keyset_path: name of the file with the keyset to be used for encryption or
    decryption
  input_path: name of the file with the input data to be encrypted or decrypted
  output_path: name of the file to write the ciphertext respectively plaintext
    to
  [optional] associated_data: the associated data used for encryption/decryption
    provided as a string.
"""

from typing import BinaryIO

from absl import app
from absl import flags
from absl import logging
import tink
from tink import secret_key_access
from tink import streaming_aead

FLAGS = flags.FLAGS
BLOCK_SIZE = 1024 * 1024  # The CLI tool will read/write at most 1 MB at once.

flags.DEFINE_enum('mode', None, ['encrypt', 'decrypt'],
                  'Selects if the file should be encrypted or decrypted.')
flags.DEFINE_string('keyset_path', None,
                    'Path to the keyset used for encryption or decryption.')
flags.DEFINE_string('input_path', None, 'Path to the input file.')
flags.DEFINE_string('output_path', None, 'Path to the output file.')
flags.DEFINE_string('associated_data', None,
                    'Associated data used for the encryption or decryption.')


def read_as_blocks(file: BinaryIO):
  """Generator function to read from a file BLOCK_SIZE bytes.

  Args:
    file: The file object to read from.

  Yields:
    Returns up to BLOCK_SIZE bytes from the file.
  """
  while True:
    data = file.read(BLOCK_SIZE)
    # If file was opened in rawIO, EOF is only reached when b'' is returned.
    # pylint: disable=g-explicit-bool-comparison
    if data == b'':
      break
    # pylint: enable=g-explicit-bool-comparison
    yield data


def encrypt_file(input_file: BinaryIO, output_file: BinaryIO,
                 associated_data: bytes,
                 primitive: streaming_aead.StreamingAead):
  """Encrypts a file with the given streaming AEAD primitive.

  Args:
    input_file: File to read from.
    output_file: File to write to.
    associated_data: Associated data provided for the AEAD.
    primitive: The streaming AEAD primitive used for encryption.
  """
  with primitive.new_encrypting_stream(output_file,
                                       associated_data) as enc_stream:
    for data_block in read_as_blocks(input_file):
      enc_stream.write(data_block)


def decrypt_file(input_file: BinaryIO, output_file: BinaryIO,
                 associated_data: bytes,
                 primitive: streaming_aead.StreamingAead):
  """Decrypts a file with the given streaming AEAD primitive.

  This function will cause the program to exit with 1 if the decryption fails.

  Args:
    input_file: File to read from.
    output_file: File to write to.
    associated_data: Associated data provided for the AEAD.
    primitive: The streaming AEAD primitive used for decryption.
  """
  try:
    with primitive.new_decrypting_stream(input_file,
                                         associated_data) as dec_stream:
      for data_block in read_as_blocks(dec_stream):
        output_file.write(data_block)
  except tink.TinkError as e:
    logging.exception('Error decrypting ciphertext: %s', e)
    exit(1)


def main(argv):
  del argv

  associated_data = b'' if not FLAGS.associated_data else bytes(
      FLAGS.associated_data, 'utf-8')

  # Initialise Tink.
  try:
    streaming_aead.register()
  except tink.TinkError as e:
    logging.exception('Error initialising Tink: %s', e)
    return 1

  # Read the keyset into a keyset_handle.
  with open(FLAGS.keyset_path, 'rt') as keyset_file:
    try:
      text = keyset_file.read()
      keyset_handle = tink.json_proto_keyset_format.parse(
          text, secret_key_access.TOKEN
      )
    except tink.TinkError as e:
      logging.exception('Error reading key: %s', e)
      return 1

  # Get the primitive.
  try:
    streaming_aead_primitive = keyset_handle.primitive(
        streaming_aead.StreamingAead)
  except tink.TinkError as e:
    logging.exception('Error creating streaming AEAD primitive from keyset: %s',
                      e)
    return 1

  # Encrypt or decrypt the file.
  with open(FLAGS.input_path, 'rb') as input_file:
    with open(FLAGS.output_path, 'wb') as output_file:
      if FLAGS.mode == 'encrypt':
        encrypt_file(input_file, output_file, associated_data,
                     streaming_aead_primitive)
      elif FLAGS.mode == 'decrypt':
        decrypt_file(input_file, output_file, associated_data,
                     streaming_aead_primitive)


if __name__ == '__main__':
  flags.mark_flag_as_required('mode')
  flags.mark_flag_as_required('keyset_path')
  flags.mark_flag_as_required('input_path')
  flags.mark_flag_as_required('output_path')
  app.run(main)
streaming_aead_cli.py

Streaming AEAD

Primitive Streaming AEAD menyediakan enkripsi yang diotentikasi untuk streaming data. Primitive ini berguna jika data yang akan dienkripsi terlalu besar untuk diproses dalam satu langkah. Kasus penggunaan umum mencakup enkripsi file besar atau aliran data langsung.

Enkripsi dilakukan dalam segmen, yang terikat ke lokasinya dalam teks tersandi dan tidak dapat dihapus atau diurutkan ulang. Segmen dari satu teks tersandi tidak dapat disisipkan ke teks tersandi lain. Untuk mengubah teks tersandi yang ada, seluruh aliran data harus dienkripsi ulang.¹

Dekripsi cepat karena hanya sebagian teks tersandi yang didekripsi dan diotentikasi pada satu waktu. Teks polos parsial dapat diperoleh tanpa memproses seluruh teks tersandi.

Implementasi Streaming AEAD memenuhi definisi AEAD dan aman dari nOAE. Implementasi ini memiliki properti berikut:

Secrecy: Tidak ada yang diketahui tentang teks polos, kecuali panjangnya.
Keaslian: Teks polos terenkripsi yang mendasari teks tersandi tidak dapat diubah tanpa terdeteksi.
Simetris: Enkripsi teks polos dan dekripsi teks tersandi dilakukan dengan kunci yang sama.
Pengacakan: Enkripsi diacak. Dua pesan dengan teks polos yang sama menghasilkan teks tersandi yang berbeda. Penyerang tidak dapat mengetahui teks tersandi mana yang sesuai dengan teks polos tertentu.

Data terkait

Primitive Streaming AEAD dapat digunakan untuk mengaitkan teks tersandi ke data terkait tertentu. Misalnya, Anda memiliki database dengan kolom user-id dan encrypted-medical-history: Dalam skenario ini, user-id dapat digunakan sebagai data terkait saat mengenkripsi encrypted-medical-history. Hal ini mencegah penyerang memindahkan histori medis dari satu pengguna ke pengguna lain.

Memilih jenis kunci

Sebaiknya gunakan AES128_GCM_HKDF_1MB untuk sebagian besar penggunaan. Umumnya:

AES-GCM-HKDF
- AES128_GCM_HKDF_1MB (atau AES256_GCM_HKDF_1MB) adalah opsi yang lebih cepat. Opsi ini dapat mengenktipsi 2⁶⁴ file dengan masing-masing hingga 2⁶⁴ byte. ~1 MB memori digunakan selama proses enkripsi dan dekripsi.
- AES128_GCM_HKDF_4KB menggunakan ~4 KB memori dan merupakan pilihan yang baik jika sistem Anda tidak memiliki banyak memori.
AES-CTR HMAC
- AES128_CTR_HMAC_SHA256_1MB (atau AES256_CTR_HMAC_SHA256_1MB) adalah opsi yang lebih konservatif.

Jaminan keamanan

Implementasi Streaming AEAD menawarkan:

Keamanan CCA2.
Kekuatan autentikasi minimal 80 bit.
Kemampuan untuk mengenkripsi minimal 2⁶⁴ pesan³ dengan total 2⁵¹ byte² . Tidak ada serangan dengan hingga 2³² teks polos yang dipilih atau teks tersandi yang dipilih yang memiliki probabilitas keberhasilan lebih besar dari 2^-32.

Alasan pembatasan ini adalah penggunaan cipher AES-GCM. Mengenkripsi segmen teks polos yang berbeda di lokasi yang sama akan setara dengan menggunakan kembali IV, yang melanggar jaminan keamanan AES-GCM. Alasan lainnya adalah untuk mencegah serangan roll-back, yang dapat dilakukan penyerang dengan mencoba memulihkan versi file sebelumnya tanpa terdeteksi. ↩
2³² segmen didukung, dengan setiap segmen berisi segment_size - tag_size byte teks polos. Untuk segmen 1 MB, ukuran teks polos total adalah 2³² * (2²⁰-16) ~= 2⁵¹ byte. ↩
Streaming AEAD menjadi tidak aman jika kombinasi kunci turunan (128 bit) dan awalan nonce (nilai 7 byte acak independen) diulang. Kami memiliki ketahanan tabrakan 184 bit, yang secara kasar diterjemahkan menjadi 2⁶⁴ pesan jika kami ingin probabilitas keberhasilan kurang dari 2^-32. ↩