我正在尝试在 IOS 中解密我的文件。该文件在 C# 应用程序中使用 AES 加密。
这是我的IOS解密方法:
- (NSData *)AES128OperationCCOperation)operation keyNSString *)key ivNSString *)iv
{
NSLog(@"inside AES128Operation");
char keyPtr[kCCKeySizeAES128 + 1];
bzero(keyPtr, sizeof(keyPtr));
[key getCString:keyPtr maxLength:sizeof(keyPtr) encoding:NSUTF8StringEncoding];
char ivPtr[kCCBlockSizeAES128 + 1];
bzero(ivPtr, sizeof(ivPtr));
if (iv) {
[iv getCString:ivPtr maxLength:sizeof(ivPtr) encoding:NSUTF8StringEncoding];
}
NSUInteger dataLength = [self length];
size_t bufferSize = dataLength + kCCBlockSizeAES128;
void *buffer = malloc(bufferSize);
size_t numBytesEncrypted = 0;
CCCryptorStatus cryptStatus = CCCrypt(operation,
kCCAlgorithmAES128,
kCCOptionPKCS7Padding | kCCOptionECBMode,
keyPtr,
kCCBlockSizeAES128,
ivPtr,
[self bytes],
dataLength,
buffer,
bufferSize,
&numBytesEncrypted);
if (cryptStatus == kCCSuccess) {
return [NSData dataWithBytes:buffer length:numBytesEncrypted];
}
free(buffer);
return nil;
}
以及我使用它的方式:
NSString *strKey = MyKey;
NSString *strIv = MyIV;
NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory , NSUserDomainMask, YES);
NSString *documentsDir = [paths objectAtIndex:0];
NSString *pathLocal_encrypted = [documentsDir stringByAppendingPathComponent"encrypted.file"];
NSData *data_encrpted = [[NSFileManager defaultManager] contentsAtPath:pathLocal_encrypted];
NSData *decryptedData = [data_encrpted AES128DecryptedDataWithKey:strKey iv:strIv];
IV 是一个 8 字节的向量。
最终解密的文件不可读或解密错误。
我还在一些测试文件上使用“AES128Operation”方法尝试在 ios 应用程序中加密/解密,它运行良好但不知道为什么它不能解密 C# 加密文件。
使用此代码(相同文件、相同 iv、相同、 key )在 C# 中解密效果很好:
static byte[] GetBytes(string str)
{
byte[] bytes = new byte[str.Length * sizeof(char)];
System.Buffer.BlockCopy(str.ToCharArray(), 0, bytes, 0, bytes.Length);
return bytes;
}
private static byte[] DecryptBytes(SymmetricAlgorithm alg, byte[] message)
{
if ((message == null) || (message.Length == 0))
{
return message;
}
using (var stream = new MemoryStream())
{
using (var decryptor = alg.CreateDecryptor())
using (var encrypt = new CryptoStream(stream, decryptor, CryptoStreamMode.Write))
{
encrypt.Write(message, 0, message.Length);
encrypt.FlushFinalBlock();
}
return stream.ToArray();
}
}
path = openFileDialog1.FileName;
byte[] encMessage = StreamFile(path);
byte[] decMessage;
byte[] rkey = GetBytes(Mykey);
byte[] riv = GetBytes(MyIv);
using (var rijndael = new RijndaelManaged())
{
rijndael.Key = rkey;
rijndael.IV = riv;
decMessage = DecryptBytes(rijndael, encMessage);
}
由于回答建议我尝试了这个但仍然没有希望:
NSData *key = [NSData dataWithData:[strKey dataUsingEncoding:NSUTF8StringEncoding]];
NSData *iv = [NSData dataWithData:[strIv dataUsingEncoding:NSUTF8StringEncoding]];
NSData *decryptedData = [self doCipher:data_encrpted iv:iv key:key context:kCCDecrypt];
和新功能:
- (NSData *)doCipherNSData *)dataIn
ivNSData *)iv
keyNSData *)symmetricKey
contextCCOperation)encryptOrDecrypt
{
CCCryptorStatus ccStatus = kCCSuccess;
size_t cryptBytes = 0; // Number of bytes moved to buffer.
NSMutableData *dataOut = [NSMutableData dataWithLength:dataIn.length + kCCBlockSizeAES128];
ccStatus = CCCrypt( encryptOrDecrypt,
kCCAlgorithmAES128,
kCCOptionPKCS7Padding,
symmetricKey.bytes,
kCCKeySizeAES128,
iv.bytes,
dataIn.bytes,
dataIn.length,
dataOut.mutableBytes,
dataOut.length,
&cryptBytes);
NSLog(@"CCCrypt status: %d", ccStatus);
dataOut.length = cryptBytes;
NSLog(@"CCCrypt ataOut.length: %d", dataOut.length);
return dataOut;
}
这是 C# 中的加密\解密设置:
public RijndaelManaged GetRijndaelManaged(string secretKey, string iv)
{
var keyBytes = new byte[16];
var secretKeyBytes = Encoding.UTF8.GetBytes(secretKey);
Array.Copy(secretKeyBytes, keyBytes, Math.Min(keyBytes.Length, secretKeyBytes.Length));
var ivBytes = new byte[16];
var secretIvBytes = Encoding.UTF8.GetBytes(iv);
Array.Copy(secretIvBytes, ivBytes, Math.Min(ivBytes.Length, secretIvBytes.Length));
return new RijndaelManaged
{
Mode = CipherMode.CBC,
Padding = PaddingMode.PKCS7,
KeySize = 128,
BlockSize = 128,
Key = keyBytes,
IV = ivBytes
};
}
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);
}
Best Answer-推荐答案 strong>
AES 的 iv 与 block 大小相同:128 位(16 字节),问题指出:“IV 是一个 8 字节向量”,这是不正确的。
由于您使用的是 iv,因此模式应为 CBC,但代码指定了 kCCOptionECBMode ,请删除它,iOS(通用加密)上的默认设置为 CBC 模式。
请注意,RijndaelManaged 默认为 CBC 模式和 PKCS#7 填充。但是,如果未明确设置,则 key 大小由所提供 key 的长度决定,并被填充为支持的 key 长度。最好显式设置它,在 RijndaelManaged 中使用 KeySize 参数(以位为单位)。
AES 的 block 大小为 128 位,但 RijndaelManaged 支持多种 block 大小,AESManaged 是 AES 加密的更好选择。这可能不是问题。最好显式设置它,在 RijndaelManaged 中使用值为 128 的 BlockSize 参数。
关于c# - IOS 中的 AES 解密没有给出确切的结果,我们在Stack Overflow上找到一个类似的问题:
https://stackoverflow.com/questions/31066698/
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