C＃解密使用RijndaelManaged的和CryptoStream的MP3文件 [英] C# Decrypting mp3 file using RijndaelManaged and CryptoStream
问题描述
我已经解密并保存MP3文件到Blob存储。
然而，当我解密和下载的文件我不能播放。我用一个MP3的验证工具，它说：未知文件格式。我认为这是不工作，因为它的工作原理，下载未加密的MP3文件解密。下面我第一次展现其Azure的webjob函数内部加密code。在我展示解密方法和使用它的方法。我已删除键和这样或清晰的处理。
加密
公共静态无效EncryptBlob（
[BlobTrigger（callstest / {名}）]
[斑点（callstest /（名称），FileAccess.Read）流blobInput，
[斑点（encryptedcalls / {name}的.vega，FileAccess.Write）流blobOutput）
{
尝试
{
VAR密码=myKey123;
VAR UE =新的Uni codeEncoding（）;
VAR键= ue.GetBytes（密码）;
VAR rmCrypto =新RijndaelManaged的{填充= PaddingMode.None}; 使用（VAR CS =新的CryptoStream（blobOutput，
rmCrypto.CreateEncryptor（键，键），
CryptoStreamMode.Write））
{
int数据;
而（（数据= blobInput.ReadByte（））！= -1）
cs.WriteByte（（字节）的数据）;
} }
抓住
{
Trace.TraceError（加密过程中发生了错误的文件，得到的名字吗？）;
}
}
AdminController
公共异步任务＆LT;＆的ActionResult GT; DownloadMp3FromUrl（）
{
var文件=等待_recordingService.GetRecordingFromUrl（）;
变种文件名=filetest.mp3;
返回File（文件，音频/ MPEG，文件名）;
}
录音服务处理器
公共异步任务＆LT;字节[]＆GT; GetRecordingFromUrl（）
{
变种容器= _blobClient.GetContainerReference（encryptedcalls）; 变种blockBlob = container.GetBlockBlobReference（SearchFiles.mp3.vega）; 尝试
{
VAR密码=myKey123;
VAR UE =新的Uni codeEncoding（）;
VAR键= ue.GetBytes（密码）;
VAR rmCrypto =新RijndaelManaged的{填充= PaddingMode.None}; 使用（VAR流=新的MemoryStream（））
{
blockBlob.FetchAttributes（）;
blockBlob.DownloadToStream（流，NULL，NULL）;
使用（VAR CS =新的CryptoStream（流rmCrypto.CreateDecryptor（键，键），CryptoStreamMode.Read））
{
int数据;
而（（数据= stream.ReadByte（））！= -1）
cs.WriteByte（（字节）的数据）; 返回stream.ToArray（）;
}
}
}
抓住
{
Trace.TraceError（加密过程中发生了错误的文件，得到的名字吗？）;
}
返回null;
}
您正试图解密后的数据写的回的放入您的录音服务处理程序源流。这不会工作。我很惊讶，这并不抛出异常。
您需要设置你的输入流，它传递到解密的CryptoStream，然后写这为其他输出流：
使用（VAR inStream中=新的MemoryStream（））
使用（VAR outStream =新的MemoryStream（））
{
blockBlob.FetchAttributes（）;
blockBlob.DownloadToStream（插播广告，NULL，NULL）;
使用（VAR的CryptoStream =新的CryptoStream（
视频插播rmCrypto.CreateDecryptor（键，键），CryptoStreamMode.Read））
{
cryptoStream.CopyTo（outStream）;
返回outStream.ToArray（）;
}
}
顺便说一句，执行如你$ P $这里psented它的完全的安全问题：
- 请不要使用非填充密码。您可以泄露信息的这种方式。
- 请不要生成一个密码密钥。使用<一个href=\"https://msdn.microsoft.com/en-us/library/system.security.cryptography.rngcryptoserviceprovider%28v=vs.110%29.aspx\"相对=nofollow>密码安全RNG 来生成你的钥匙。
- 如果您的必须的使用字符串作为你的密钥的密码，使用Rfc2898DeriveBytes来生成密码的加密安全随机密钥。
- 绝对的不的使用对称密钥作为IV。这是真的，真的不好的做法。该四用于随机密码的输出 - 这是不以同样的方式作为一个秘密键，并应是唯一的被加密的每个信息（或文件）。
I have decrypted and saved an mp3 file into a blob storage.
However, when I decrypt and download the file I cant play it. I used an Mp3 validation tool which says "unknown file format". I believe it is the decryption that does not work since it works to download an unencrypted Mp3 file. Below I first show the encryption code within its Azure webjob function. The I show the decryption method and the method using it. I have removed handling of keys and such or clarity.
Encrypt
public static void EncryptBlob(
[BlobTrigger("callstest/{name}")]
[Blob("callstest/{name}", FileAccess.Read)] Stream blobInput,
[Blob("encryptedcalls/{name}.vega", FileAccess.Write)] Stream blobOutput)
{
try
{
var password = "myKey123";
var ue = new UnicodeEncoding();
var key = ue.GetBytes(password);
var rmCrypto = new RijndaelManaged {Padding = PaddingMode.None};
using (var cs = new CryptoStream(blobOutput,
rmCrypto.CreateEncryptor(key, key),
CryptoStreamMode.Write))
{
int data;
while ((data = blobInput.ReadByte()) != -1)
cs.WriteByte((byte)data);
}
}
catch
{
Trace.TraceError("an error occured during encryption of the file-get the name?");
}
}
AdminController
public async Task<ActionResult> DownloadMp3FromUrl()
{
var file = await _recordingService.GetRecordingFromUrl();
var fileName = "filetest.mp3";
return File(file,"audio/mpeg", fileName);
}
Recording Service handler
public async Task<byte[]> GetRecordingFromUrl()
{
var container = _blobClient.GetContainerReference("encryptedcalls");
var blockBlob = container.GetBlockBlobReference("SearchFiles.mp3.vega");
try
{
var password = "myKey123";
var ue = new UnicodeEncoding();
var key = ue.GetBytes(password);
var rmCrypto = new RijndaelManaged { Padding = PaddingMode.None };
using (var stream = new MemoryStream())
{
blockBlob.FetchAttributes();
blockBlob.DownloadToStream(stream, null, null);
using (var cs = new CryptoStream(stream, rmCrypto.CreateDecryptor(key, key), CryptoStreamMode.Read))
{
int data;
while ((data = stream.ReadByte()) != -1)
cs.WriteByte((byte)data);
return stream.ToArray();
}
}
}
catch
{
Trace.TraceError("an error occured during encryption of the file-get the name?");
}
return null;
}
You're trying to write the decrypted data back into the source-stream in your Recording Service handler. This will never work. I'm amazed this doesn't throw an exception.
You need to set up your input stream, pass it into a decrypting CryptoStream, then write that to another output stream:
using (var inStream = new MemoryStream())
using (var outStream = new MemoryStream())
{
blockBlob.FetchAttributes();
blockBlob.DownloadToStream(inStream, null, null);
using (var cryptoStream = new CryptoStream(
inStream, rmCrypto.CreateDecryptor(key, key), CryptoStreamMode.Read))
{
cryptoStream.CopyTo(outStream);
return outStream.ToArray();
}
}
As an aside, the implementation as you've presented it here is full of security issues:
- Don't use a non-padded cipher. You can leak information this way.
- Don't generate your key from a password. Use a cryptographically secure RNG to generate your keys.
- If you must use a string as your key's password, use Rfc2898DeriveBytes to generate a cryptographically secure random key from the password.
- Absolutely do not use your symmetric key as your IV. This is really, really bad practice. The IV is used to randomize the cipher's output - it is not a secret in the same way as the key, and should be unique to each 'message' (or file) being encrypted.
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