.NET Secure Memory Structures

Question

I know the .NET library offers a way of storing a string in a protected/secure manner = SecureString.

My question is, if I would like to store a byte array, what would be the best, most secure container to hold this?

Answer 1

You could use SecureString to store the byte array.

  SecureString testString = new SecureString();

  // Assign the character array to the secure string.
  foreach (byte b in bytes)
     testString.AppendChar((char)b);

then you just reverse the process to get the bytes back out.

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This isn't the only way, you can always use a MemoryBuffer and and something out of System.Security.Cryptography. But this is the only thing specifically designed to be secure in this way. All others you would have to create with the System.Security.Cryptography, which is probably the best way for you to go.

Answer 2

One option:

You could store the bytes in a memory stream, encrypted using any of the providers in the System.Security.Cryptography namespace.

Answer 3

encrypt your byte array with any of cryptographic methods for example RijndaelManaged , and than store wherever you like :)

Answer 4

There is no "best" way to do this - you need to identify the threat you are trying to protect against in order to decide what to do or indeed if anything needs to be done.

One point to note is that, unlike a string which is immutable, you can zero out the bytes in a byte array after you've finished with them, so you won't have the same set of problems that SecureString is designed to solve.

Encrypting data could be appropriate for some set of problems, but then you will need to identify how to protect the key from unauthorized access.

I find it difficult to imagine a situation where encrypting a byte array in this way would be useful. More details of exactly what you're trying to do would help.