Peter said:
shapper said:
Hello,
I am writing some Byte arrays to an XElement to save on a XML file.
In some cases this byte array might contain a small image.
I am doing it as follows:
XElement node = new XElement("Node",
new XElement("ByteTest1", Convert.ToBase64String(new Byte[]
{ 0, 1, 2, 3, 4, 5, 6, 7, 8, 9 })),
new XElement("ByteTest2", new Byte[] { 0, 1, 2, 3, 4, 5, 6, 7,
8, 9 })
);
Console.WriteLine(node);
I get the following:
<Node>
<ByteTest1>AAECAwQFBgcICQ==</ByteTest1>
<ByteTest2>0123456789</ByteTest2>
</Node>
Should I use Convert.ToBase64String? In which case shouldn't I use it?
And if I should always use it is it possible, or it makes sense, to
create a XElement extension that when the value is of type Byte[] it
uses Base64String?
You will always want to use Base64. Stop and think about that
"ByteTest2": assuming your array will ever have some byte value in it
other than zero through nine, how are you going to reverse the encoding?
That is, how will you read the text in the XML element and convert it
back to a byte[]?
Pete
It can be done several years ago i wrote a simple class for doing just this.
using System;
using System.Text;
using JJMath.Big;
namespace JJSecurity.Encryption.RSA
{
class Blocking
{
private BigInteger[] blocks;
private int blockSize = -1;
private String plainText;
public BigInteger[] Blocks { get { return this.blocks; } }
public String PlainText { get { return this.plainText; } }
public Blocking(String toBlock, int blockSize)
{
this.blockSize = (blockSize / 2);
this.GenerateBlocks(this.GenerateByteString(toBlock));
}
public Blocking(String toUnBlock)
{
try
{
this.GenerateCharacterStringFromByteString(toUnBlock);
}
catch
{
throw new Exception("Unable to Create Character String
From Byte String");
}
}
private void GenerateBlocks(String toEncrypt)
{
if (toEncrypt.Length > this.blockSize)
{
int division = (toEncrypt.Length / this.blockSize);
int mod = (toEncrypt.Length % this.blockSize);
BigInteger[] blocks;
if (mod != 0)
blocks = new BigInteger[(division + 1)];
else
blocks = new BigInteger[division];
int blockSize = (toEncrypt.Length / blocks.Length);
int index = 0;
Random random = new Random();
for (int i = 0; i < blocks.Length; i++)
{
if ((i == division) && (mod != 0))
{
blocks
= new BigInteger(random.Next(1,
9).ToString() + toEncrypt.Substring(index), 10);
}
else
{
blocks = new BigInteger(random.Next(1,
9).ToString() + toEncrypt.Substring(index, blockSize), 10);
}
index += blockSize;
}
this.blocks = blocks;
}
else
{
this.blocks = new BigInteger[] { new BigInteger(new
Random().Next(1, 9).ToString() + toEncrypt, 10) };
}
}
private String GenerateByteString(String toEncrypt)
{
byte[] bytes = Encoding.UTF8.GetBytes(toEncrypt);
StringBuilder sb = new StringBuilder((toEncrypt.Length * 3));
for (int i = 0; i < bytes.Length; i++)
{
switch (bytes.ToString().Length)
{
case 1:
sb.Append("00");
sb.Append(bytes);
break;
case 2:
sb.Append("0");
sb.Append(bytes);
break;
case 3:
sb.Append(bytes);
break;
}
}
return sb.ToString();
}
private void GenerateCharacterStringFromByteString(String toChange)
{
byte[] bytes = new byte[toChange.Length / 3];
int charIndex = 0;
for (int i = 0; i < bytes.Length; i++)
{
String bytePart = toChange[charIndex].ToString() +
toChange[(charIndex + 1)].ToString() +
toChange[(charIndex + 2)].ToString();
bytes = Byte.Parse(bytePart);
charIndex += 3;
}
this.plainText = Encoding.UTF8.GetString(bytes);
}
}
}
Hope this helps.