AES/GCM的颤振加密(Dart)
AES/GCM的颤振加密(Dart)
提问于 2021-03-05 07:56:34
我正在尝试在颤振中实现AES/GCM/NoPadding加密。我已经在JAVA中成功地实现了它，但是当我试图在颤栗中解密它时，我没有成功。
我试过用dart编写解密代码，但是我得到了未处理的异常: SecretBox有错误的消息身份验证代码(MAC)。
我的Java代码
public class GCMEncryption {
public static final int AES_KEY_SIZE = 128;
public static final int GCM_IV_LENGTH = 12;
public static final int GCM_TAG_LENGTH = 16;
public String getEncryptedText(String plainText) {
try {
byte[] IV = new byte[GCM_IV_LENGTH];
SecureRandom random = new SecureRandom();
random.nextBytes(IV);
String iv = Base64.getEncoder().encodeToString(IV);
System.out.println("IV : "+iv);
byte[] cipherText = encrypt(plainText.getBytes(), getKeySpec(), IV);
String text = Base64.getEncoder().encodeToString(cipherText);
text = iv+text; // Concating iv and encrypted text together
return text;
} catch (Exception e) {
e.printStackTrace();
return "";
}
}
public String getDecryptedText(String cipherText) {
try {
// Splitting IV and Encrypted text
String iv = cipherText.substring(0,16);
System.out.println("IV : "+iv);
byte[] IV = Base64.getDecoder().decode(iv);
cipherText = cipherText.substring(16);
byte[] data = Base64.getDecoder().decode(cipherText);
return decrypt(data, getKeySpec(), IV);
} catch (Exception e) {
e.printStackTrace();
return "";
}
}
private SecretKeySpec getKeySpec() {
SecretKeySpec spec = null;
try {
byte[] bytes = new byte[32];
String pwd = "Test!ng012345678"; //Temporary
bytes = pwd.getBytes();
spec = new SecretKeySpec(bytes, "AES");
return spec;
} catch (Exception e) {
e.printStackTrace();
}
return spec;
}
private byte[] encrypt(byte[] plaintext, SecretKey key, byte[] IV) throws Exception {
// Get Cipher Instance
Cipher cipher = Cipher.getInstance("AES/GCM/NoPadding");
// Create SecretKeySpec
SecretKeySpec keySpec = new SecretKeySpec(key.getEncoded(), "AES");
// Create GCMParameterSpec
GCMParameterSpec gcmParameterSpec = new GCMParameterSpec(GCM_TAG_LENGTH * 8, IV);
// Initialize Cipher for ENCRYPT_MODE
cipher.init(Cipher.ENCRYPT_MODE, keySpec, gcmParameterSpec);
// Perform Encryption
byte[] cipherText = cipher.doFinal(plaintext);
return cipherText;
}
private String decrypt(byte[] cipherText, SecretKey key, byte[] IV) throws Exception {
// Get Cipher Instance
Cipher cipher = Cipher.getInstance("AES/GCM/NoPadding");
// Create SecretKeySpec
SecretKeySpec keySpec = new SecretKeySpec(key.getEncoded(), "AES");
// Create GCMParameterSpec
GCMParameterSpec gcmParameterSpec = new GCMParameterSpec(GCM_TAG_LENGTH * 8, IV);
// Initialize Cipher for DECRYPT_MODE
cipher.init(Cipher.DECRYPT_MODE, keySpec, gcmParameterSpec);
// Perform Decryption
byte[] decryptedText = cipher.doFinal(cipherText);
return new String(decryptedText);
}
}我的Dart密码
Future<String> decrypt(String textBlock) async {
Uint8List data = base64.decode("4NA09I5VpmdD0o1k3VP8eIfyZRKDtzOwgJv5nh0nmEPZ/Q==");
Uint8List passphrase = utf8.encode('Test!ng012345678');
SecretKey secretKey = new SecretKey(passphrase);
Uint8List iv = utf8.encode('/U0OI/AdHDM4QFVC');
SecretBox secretBox = new SecretBox(data, nonce: iv);
List<int> decrypted = await AesGcm.with128bits().decrypt(secretBox, secretKey: secretKey);
String dec = utf8.decode(decrypted);
print("DATA : "+dec);
return dec;
}为此，我得到了以下的颤振误差。
未处理的异常：(package:cryptography/src/dart/aes_gcm.dart:112:7) #0 DartAesGcm.decryptSync #1 DartAesGcm.decrypt (package:cryptography/src/dart/aes_gcm.dart:58:12) #2 EncryptionHandler.decrypt (package:investment_app/encryption/encryption_handler.dart:45:27) SecretBox错误消息身份验证代码(MAC) #0
你能帮我解决这个问题吗。示例代码将有帮助。
回答 1
Stack Overflow用户
回答已采纳
发布于 2021-03-05 10:43:34
Java中的SunJCE提供程序将密文和MAC连接起来:密文\MAC。在Dart代码中，两者都必须单独指定，这在已发布的代码中不会发生。而且，IV没有被Base64解码。
下面的代码是修复bug的可能实现：
Uint8List ivCiphertextMac = base64.decode("/U0OI/AdHDM4QFVC4NA09I5VpmdD0o1k3VP8eIfyZRKDtzOwgJv5nh0nmEPZ/Q=="); // from the Java code
Uint8List iv = ivCiphertextMac.sublist(0, 12);
Uint8List ciphertext = ivCiphertextMac.sublist(12, ivCiphertextMac.length - 16);
Uint8List mac = ivCiphertextMac.sublist(ivCiphertextMac.length - 16);
Uint8List passphrase = utf8.encode('Test!ng012345678');
SecretKey secretKey = new SecretKey(passphrase);
SecretBox secretBox = new SecretBox(ciphertext, nonce: iv, mac: new Mac(mac));
List<int> decrypted = await AesGcm.with128bits().decrypt(secretBox, secretKey: secretKey);
String dec = utf8.decode(decrypted);
print("Decrypted text : " + dec); // Decrypted text : Mayur, You got it!解密结果是: Mayur，你知道了！
实际上，SecretBox提供了将IV、密文和MAC连接起来的方法fromConcatenation()。但是这个实现似乎返回了一个损坏的密文，这可能是一个bug。
编辑：
关于您在评论中的问题: MAC是在加密期间自动生成的。下面的代码实现了加密，其中ivCiphertextMacB64包含IV #加密文本的Base64编码：
Uint8List plaintext = utf8.encode("Mayur, You got it!");
Uint8List iv = AesGcm.with128bits().newNonce();
Uint8List passphrase = utf8.encode('Test!ng012345678');
SecretKey secretKey = new SecretKey(passphrase);
SecretBox secretBox = await AesGcm.with128bits().encrypt(plaintext, nonce: iv, secretKey: secretKey);
String ivCiphertextMacB64 = base64.encode(secretBox.concatenation()); // Base64 encoding of: IV | ciphertext | MAC
print("ivCiphertextMacB64 : " + ivCiphertextMacB64);页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持
原文链接：
https://stackoverflow.com/questions/66488767
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