Question

我正在使用c＃进行AES Decryption，因为解密后的数据在解密后的最后几个字符中显示了一些垃圾数据。

我使用下面的代码进行解密

+ (NSData*)decryptData:(NSData*)data key:(NSData*)key iv:(NSData*)iv;
{
   NSData* result = nil;

// setup key
unsigned char cKey[FBENCRYPT_KEY_SIZE];
bzero(cKey, sizeof(cKey));
[key getBytes:cKey length:FBENCRYPT_KEY_SIZE];

// setup iv
char cIv[FBENCRYPT_BLOCK_SIZE];
bzero(cIv, FBENCRYPT_BLOCK_SIZE);
NSLog(@"CIV2 : %s",cIv);

if (iv) {
    [iv getBytes:cIv length:FBENCRYPT_BLOCK_SIZE];
}

// setup output buffer
size_t bufferSize = [data length] + FBENCRYPT_BLOCK_SIZE;
void *buffer = malloc(bufferSize);

// do decrypt
size_t decryptedSize = 0;
CCCryptorStatus cryptStatus = CCCrypt(kCCDecrypt,
                                      FBENCRYPT_ALGORITHM,  //kCCAlgorithmAES128
                                      kCCOptionPKCS7Padding,
                                      cKey,                    //16
                                      FBENCRYPT_KEY_SIZE,   //16
                                      cKey,
                                      [data bytes],
                                      [data length],
                                      buffer,
                                      bufferSize,
                                      &decryptedSize);

if (cryptStatus == kCCSuccess) {

    result = [NSData dataWithBytesNoCopy:buffer length:decryptedSize];
} else {
    free(buffer);
    NSLog(@"[ERROR] failed to decrypt| CCCryptoStatus: %d", cryptStatus);
}

return result;

}

如果您在调试中看到结果，它将显示最后一些字符吃垃圾但解密完整数据。

NSData* data = [self decryptData:encryptedData
                             key:[keyString dataUsingEncoding:NSUTF8StringEncoding]
                              iv:nil];

if (data) {
    return [[NSString alloc] initWithData:data
                                  encoding:NSUTF8StringEncoding];

}

数据返回零值。

C＃代码如下。

public RijndaelManaged GetRijndaelManaged(String secretKey)
{
    var keyBytes = new byte[16];
    var secretKeyBytes = Encoding.UTF8.GetBytes(secretKey);
    Array.Copy(secretKeyBytes, keyBytes, Math.Min(keyBytes.Length, secretKeyBytes.Length));
    return new RijndaelManaged
    {
        Mode = CipherMode.CBC,
        Padding = PaddingMode.PKCS7,
        KeySize = 128,
        BlockSize = 128,
        Key = keyBytes,
        IV = keyBytes
    };
}

public byte[] Encrypt(byte[] plainBytes, RijndaelManaged rijndaelManaged)
{
    return rijndaelManaged.CreateEncryptor()
        .TransformFinalBlock(plainBytes, 0, plainBytes.Length);
}

public byte[] Decrypt(byte[] encryptedData, RijndaelManaged rijndaelManaged)
{
    return rijndaelManaged.CreateDecryptor()
        .TransformFinalBlock(encryptedData, 0, encryptedData.Length);
}

/// <summary>
/// Encrypts plaintext using AES 128bit key and a Chain Block Cipher and returns a base64 encoded string
/// </summary>
/// <param name="plainText">Plain text to encrypt</param>
/// <param name="key">Secret key</param>
/// <returns>Base64 encoded string</returns>
public String Encrypt(String plainText, String key)
{
    var plainBytes = Encoding.UTF8.GetBytes(plainText);
    return Convert.ToBase64String(Encrypt(plainBytes, GetRijndaelManaged(key)));
}

/// <summary>
/// Decrypts a base64 encoded string using the given key (AES 128bit key and a Chain Block Cipher)
/// </summary>
/// <param name="encryptedText">Base64 Encoded String</param>
/// <param name="key">Secret Key</param>
/// <returns>Decrypted String</returns>
public String Decrypt(String encryptedText, String key)
{
    var encryptedBytes = Convert.FromBase64String(encryptedText);
    return Encoding.UTF8.GetString(Decrypt(encryptedBytes, GetRijndaelManaged(key)));
}

从C＃收到数据： 0Nwr30kSkJxGCYiFg8TUrfW51587SUkS8lQ7Uno7gglxjVGW5gR4MA + isTknjXzK

Key uses for encryption : e64f9fa01f0418

来自iOS的解密数据：{“Successeed”：   “abcdefghijklmnopqrstuvwx！...``〜

预期的解密数据：{“Successeed”：   “ABCDEFGHIJKLMNOPQRSTUVWXYZ”}

Answer 1

加密数据包含十六进制227d。

数据十六进制表示：
7b22537563636565646564223a226162636465666768696a6b6c6d6e6f707172737475767778797a 227d

字符串表示：
{"Succeeded":"abcdefghijklmnopqrstuvwxyz"}

注意：
最好使用全长密钥，对于AES 16,24或32字节，您的密钥是14个字节，并且将使用一些未定义的方法来扩展它。此外，IV必须是锁定大小，AES为16字节。你很幸运，实现之间的填充似乎是相同的（0x00），不要依靠运气。

测试代码：

// Explicit null pad the key and IV to correct lengths
NSData *ivData  = [@"e64f9fa01f0418\x00\x00" dataUsingEncoding:NSUTF8StringEncoding];
NSData *keyData = [@"e64f9fa01f0418\x00\x00" dataUsingEncoding:NSUTF8StringEncoding];
NSString *base64EncryptedString = @"0Nwr30kSkJxGCYiFg8TUrfW51587SUkS8lQ7Uno7gglxjVGW5gR4MA+isTknjXzK";
NSData *encryptedData = [[NSData alloc] initWithBase64EncodedString:base64EncryptedString options:0];

NSMutableData *plainData = [NSMutableData dataWithLength: encryptedData.length];
size_t movedBytes = 0;

CCCryptorStatus ccStatus;
ccStatus = CCCrypt(kCCDecrypt,
                   kCCAlgorithmAES128,
                   kCCOptionPKCS7Padding,
                   keyData.bytes, kCCKeySizeAES128,
                   ivData.bytes,
                   encryptedData.bytes, encryptedData.length,
                   plainData.mutableBytes, plainData.length,
                   &movedBytes);

plainData.length = movedBytes;
NSLog(@"Data: %@",plainData);
NSString *decryptedString = [[NSString alloc] initWithData:plainData encoding:NSUTF8StringEncoding];
NSLog(@"String: %@",decryptedString);

AES解密不适用于在Android上工作的iOS使用FBEncryptior Library

1 个答案: