Convert string into byte array

Question

Using the ProtectedData class found here I created two methods that encrypt and decrypt.

public byte[] Encrpyt(string unprotectedData)
{
    try
    {
        var rawByte = Encoding.Default.GetBytes(unprotectedData);
        var protectedByte = ProtectedData.Protect(rawByte, mEntropy, DataProtectionScope.CurrentUser);

        var sb = new StringBuilder();
        foreach (var b in protectedByte)
        {
            sb.Append(b + ",");
        }
        return sb.ToString();
    }
    catch (CryptographicException e)
    {
        Log.Error("Unable to encrypt data: " + e.Message);
        return null;
    }
}

public string Decrpyt(byte[] encryptedByte)
{
    try
    {
        var rawByte = ProtectedData.Unprotect(encryptedByte, mEntropy, DataProtectionScope.CurrentUser);
        return Encoding.Default.GetString(rawByte);
    }
    catch (CryptographicException e)
    {
        Log.Error("Unable to decrypt data: " + e.Message);
        return null;
    }
}

I'll then save the byte array to a local XML file. When I read my XML file using Xdocument it will return the byte array as a string like so:

<Password>1,0,0,0,208,140,157,223,1,21,209,17,140,122,0,192,79,194,151,235,1,0,0,0,38,216,9,185,58,253,108,75,147,117,90,37,221,16,167,39,0,0,0,0,2,0,0,0,0,0,16,102,0,0,0,1,0,0,32,0,0,0,50,46,190,245,251,118,123,109,212,25,65,59,228,112,35,12,231,87,116,180,220,108,96,93,61,94,60,131,19,3,232,12,0,0,0,0,14,128,0,0,0,2,0,0,32,0,0,0,245,81,93,64,218,37,115,108,206,224,202,116,43,234,19,61,212,166,204,96,17,126,26,232,150,250,70,99,133,158,128,234,16,0,0,0,69,74,29,51,0,61,167,191,240,205,78,93,126,83,206,189,64,0,0,0,203,223,66,5,16,98,235,67,174,91,97,5,208,0,222,134,190,239,222,0,169,211,165,22,121,150,37,232,33,180,45,196,138,101,29,220,156,128,231,137,214,207,31,170,65,96,101,252,252,53,218,220,240,140,15,92,35,27,98,222,3,151,248,247,</Password>

How can I convert the string (which is already a byte array in string format) to a byte array so I can then decrypt it?

What have you tried? Reading XML, splitting a string on comma and converting numeric strings to their byte values have all been solved... See for example [Convert comma separated string of ints to int array](http://stackoverflow.com/questions/1763613/convert-comma-separated-string-of-ints-to-int-array). — CodeCaster, Sep 14 '15 at 08:33
That's a poor way of representing the binary data to start with, IMO. Very longwinded - why not just `Convert.ToBase64String` in `Encrypt`, and `Convert.FromBase64String` in `Decrypt`? (I'd strongly advise against using `Encoding.Default`, by the way - surely you want the content of the file to be portable across systems.) — Jon Skeet, Sep 14 '15 at 08:38
@JonSkeet Thank you, I didn't think of using To/FromBase64String, the code has been refactored and now works. — Travis Boatman, Sep 14 '15 at 08:52

score 3 · Accepted Answer · answered Sep 14 '15 at 08:42

I would use a base64 encoded string to store it in the XML:

  public byte[] Encrpyt(string unprotectedData)
    {
        try
        {
            var rawByte = Encoding.UTF8.GetBytes(unprotectedData);
            var protectedByte = ProtectedData.Protect(rawByte, mEntropy, DataProtectionScope.CurrentUser);
            return System.Convert.ToBase64String(protectedByte);
        }
        catch (CryptographicException e)
        {
            Log.Error("Unable to encrypt data: " + e.Message);
            return null;
        }
    }

    public string Decrpyt(string encryptedBase64)
    {
        try
        {
            var bytes = System.Convert.FromBase64String(encryptedBase64)

            var rawByte = ProtectedData.Unprotect(bytes , mEntropy, DataProtectionScope.CurrentUser);
            return Encoding.UTF8.GetString(rawByte);
        }
        catch (CryptographicException e)
        {
            Log.Error("Unable to decrypt data: " + e.Message);
            return null;
        }
    }

score 1 · Answer 2 · edited Sep 14 '15 at 08:44

1

Try this

 var byteString = "1,0,0,0,208,140,157,223,1,21,209,17,140,122,0,192,79,194,151,235,1,0,0,0,38,216,9,185,58,253,108,75,147,117,90,37,221,16,167,39,0,0,0,0,2,0,0,0,0,0,16,102,0,0,0,1,0";

 var byteArray = byteString
   .Split(',')
   .Select(t => Byte.Parse(t))
   .ToArray();

 var decodedString = Decrpyt(byteArray);

edited Sep 14 '15 at 08:44

Dmitry Bychenko

180,369
20
160
215

answered Sep 14 '15 at 08:40

yohannist

4,166
3
35
58

That's waste of hard drive space, as you can use base64 and it's slower. – bytecode77 Sep 14 '15 at 08:47

bytecode77 · Answer 3 · 2015-09-14T08:48:57.970

0

If your binary is encrypted data, then base64 is recommended:

Convert.ToBase64String(yourByteArray)

And convert it back using

Convert.FromBase64String(yourBase64String)

This way, your data is stored safe, so it doesn't get corrupted, because base64 can be safely stored in an XML file.

Plus it is superior to using comma seperated numbers, because it's faster and doesn't consume so much space in your XML.

edited Sep 14 '15 at 08:48

answered Sep 14 '15 at 08:39

bytecode77

14,163
30
110
141

Decrypt method operates on byte array. I don't think OP can use string representation of the encrypted string – yohannist Sep 14 '15 at 08:47
I saw that and I changed my answer. base64 is the way to go, I think. – bytecode77 Sep 14 '15 at 08:47

Convert string into byte array

3 Answers3