Convert .net String object into base64 encoded string

I have a question, which Unicode encoding to use while encoding .NET string into base64? I know strings are UTF-16 encoded on Windows, so is my way of encoding is the right one?

public static String ToBase64String(this String source) {
        开发者_Python百科return Convert.ToBase64String(Encoding.Unicode.GetBytes(source));
    }

What you've provided is perfectly functional. It will produce a base64-encoded string of the bytes of your source string encoded in UTF-16.

If you're asking if UTF-16 can represent any character in your string, then yes. The only difference between UTF-16 and UTF-32 is that UTF-16 is a variable-length encoding; it uses two-bytes to represent characters within a subset, and four-bytes for all other characters.

There are no unicode characters that cannot be represented by UTF-16.

Be aware that you don't have to use UTF-16 just because that's what .NET strings use. When you create that byte array, you're free to choose any encoding that will handle all the characters in your string. For example, UTF-8 would be more efficient if the text is in a Latin-based language, but it can still handle every known character.

The most important concern is that whatever software decodes the base64 string, needs to know which encoding to apply to the byte array to re-create the original string.

Here is the Solution, I have converted a Random string conversion like you can give any size up to 10 that Base64 will output.

//This function will return a random string from the given numeric characters
public string RandomString(int size)
{
const string legalCharacters = "1234567890";
Random random = new Random();
StringBuilder builder = new StringBuilder();
char ch = '\0';

for (int i = 0; i <= size - 1; i++) {
    ch = legalCharacters(random.Next(0, legalCharacters.Length));
    builder.Append(ch);
}
return builder.ToString();
}
public const string BASE64 = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz+/";
public string DecToBase64(long lVal)
{
string sVal = null;
sVal = "";
while (lVal >= 64) {
    sVal = sVal + DecToBase64(lVal / 64);
    lVal = lVal - 64 * (lVal / 64);
}
sVal = sVal + Strings.Mid(BASE64, Convert.ToInt32(lVal) + 1, 1);
return sVal;
}

//here is how we can have result in variable:
string Base64 = "";
Base64 = DecToBase64(RandomString(10)); //this will produce a combination up-to length of 10

MSDN confirms that UnicodeEncoding class represents a UTF-16 encoding of Unicode characters.