We Keep Coding

String value system.byte[] while coverting Base64 value to string in c#

I have two LDIF files from where I am reading values and using it for comparsion using c#
One of the attribute: value in LDIF is a base64 value, need to convert it in UTF-8 format
displayName:: Rmlyc3ROYW1lTGFzdE5hbWU=
So I thought of using string -> byte[], but I am not able to use the above displayName value as string
byte[] newbytes = Convert.FromBase64String(displayname);
string displaynamereadable = Encoding.UTF8.GetString(newbytes);
In my C# code, I am doing this to retrieve the values from the ldif file
for(Entry entry ldif.ReadEntry() ) //reads value from ldif for particular user's
{
foreach(Attr attr in entry) //here attr gives attributes of a particular user
{
if(attr.Name.Equals("displayName"))
{
string attVal = attr.Value[0].ToString(); //here the value of String attVal is system.Byte[], so not able to use it in the next line
byte[] newbytes = Convert.FromBase64String(attVal); //here it throws an error mentioned below
string displaynamereadable = Encoding.UTF8.GetString(attVal);
}
}
}
Error:
The input is not a valid Base-64 string as it contains a non-base 64 character, more than two padding characters, or an illegal character among the padding characters.
I am trying to user attVal as String so that I can get the encoded UTf-8 value but its throwing an error.
I tried to use BinaryFormatter and MemoryStream as well, it worked but it inserted so many new chars with the original value.
Snapshot of BinaryFormatter:
object obj = attr.Value[0];
byte[] bytes = null;
BinaryFormatter bf = new BinaryFormatter();
using (MemoryStream ms = new MemoryStream())
{
bf.Serialize(ms, obj);
bytes = (ms.ToArray());
}
string d = Encoding.UTF8.GetString(bytes);
So the result after encoding should be: "FirstNameLastName"
But it gives "\u0002 \u004 \u004 ...................FirstNameLastName\v"
Thanks,

Base64 was designed to send binary data through transfer channels that only support plain text, and as a result, Base64 is always ASCII text. So if attr.Value[0] is a byte array, just interpret those bytes as string using ASCII encoding:
String attVal = Encoding.ASCII.GetString(attr.Value[0] as Byte[]);
Byte[] newbytes = Convert.FromBase64String(attVal);
String displaynamereadable = Encoding.UTF8.GetString(newbytes);
Also note, your code above was feeding attVal into that final line rather than newbytes.

Decrypting a base64 encoded string

I am encrypting a string using Setup Factory:
string Crypto.BlowfishEncryptString (
string Text,
string Key,
number LineLen = 0 )
Description:
Blowfish encrypts a string and returns a base64-encoded string containing the encrypted data.
Note: Base64 encoding is the process of encoding arbitrary data as
plain ASCII text. One common use for this type of encoding is sending
files through email. It is one of the techniques employed by the MIME
standard to send data other than plain ASCII text.
I wrote this:
encryptedPass = Crypto.BlowfishEncryptString("password123", "uniqueKey", 0);
Which prints a base-64 string:
j5b+4W25ugGZxXJZ0HCFxw==
Now to decrypt the password, in C#:
Using the snippet available for .NET here.
string enKey = "uniqueKey";
string test = "j5b+4W25ugGZxXJZ0HCFxw==";
byte[] convertedByte = Encoding.Unicode.GetBytes(test);
string hex = BitConverter.ToString(convertedByte).Replace("-", string.Empty);
Blowfish algo = new Blowfish(enKey);
string decryptedTxt = algo.decryptString(hex);
But this returns null, I tried it without decoding the base-64 as well.
EDIT:
Tried decoding the base-64 string as well:
byte[] bytes = Convert.FromBase64String(test);
string hex = BitConverter.ToString(bytes).Replace("-", string.Empty);
Blowfish algo = new Blowfish(enKey);
string decryptedTxt = algo.decryptString(hex);

"Specified value has invalid Control characters" when converting SHA512 output to string

I am attempting to create an Hash for an API.
my input is something like this:
FBN|Web|3QTC0001|RS1|260214133217|000000131127897656
And my expected output is like :
17361DU87HT56F0O9967E34FDFFDFG7UO334665324308667FDGJKD66F9888766DFKKJJR466634HH6566734JHJH34766734NMBBN463499876554234343432456
I tried the bellow but I keep getting
"Specified value has invalid Control characters. Parameter name: value"
I am actually doing this in a REST service.
public static string GetHash(string text)
{
string hash = "";
SHA512 alg = SHA512.Create();
byte[] result = alg.ComputeHash(Encoding.UTF8.GetBytes(text));
hash = Encoding.UTF8.GetString(result);
return hash;
}
What am I missing?

The problem is Encoding.UTF8.GetString(result) as the data in result is invalid UTF-8 (it's just binary goo!) so trying to convert it to text is invalid - in general, and specifically for this input - which results in the Exception being thrown.
Instead, convert the byte[] to the hex representation of said byte sequence; don't treat it as UTF-8 encoded text.
See the questions How do you convert Byte Array to Hexadecimal String, and vice versa? and How can I convert a hex string to a byte array?, which discuss several different methods of achieving this task.

In order to make this work you need to convert the individual byte elements into a hex representation
var builder = new StringBuilder();
foreach(var b in result) {
builder.AppendFormat("{0:X2}", b);
}
return builder.ToString();

You might want to consider using Base64 encoding (AKA UUEncode):
public static string GetHash(string text)
{
SHA512 alg = SHA512.Create();
byte[] result = alg.ComputeHash(Encoding.UTF8.GetBytes(text));
return Convert.ToBase64String(result);
}
For your example string, the result is
OJgzW5JdC1IMdVfC0dH98J8tIIlbUgkNtZLmOZsjg9H0wRmwd02tT0Bh/uTOw/Zs+sgaImQD3hh0MlzVbqWXZg==
It has an advantage of being more compact than encoding each byte into two characters: three bytes takes four characters with Base64 encoding or six characters the other way.

string to byte array (to string to XML) and back again

i know there are 1million questions about "string - byte array" conversion out there but none of them fit my problem.
For the installation of my software i need to save some informations from the user (serveraddress, userID, password and so on). Some of these informations need do be protected (encrypted using DPAPI). For that i have to convert the string (SecureString) to byte[]
public static byte[] StringToByte(string s)
{
return Convert.FromBase64String(s);
}
where i get my first problem. If the strings lenght is a not a multiple of 4 (s.lenght % 4 == 0) i get a "Invalid length for a Base-64 char array" error. I've read that i can (have to) add "=" to the end of the string but some of these strings may be passwords (which may contain "="). I need to store the (encrypted) data in a XML-file why i can't use Unicode encoding (i don't know why but it corrupts the XML file ... because of encoding i would suppose).
As last step i have to go back the way to get the stored data on app startup.
Does someone of you can help me solving this problem ? I don't care the output in the XML as long as it is "readable".
best regards Alex

where i get my first problem. If the strings lenght is a not a multiple of 4 (s.lenght % 4 == 0) i get a "Invalid length for a Base-64 char array" error.
That suggests that it's not base64 to start with. It sounds like you're going in the wrong direction here - base64 is used to convert binary data into text. To convert text into a binary form, you should normally just use Encoding.GetBytes:
return Encoding.UTF8.GetBytes(text);
Now if you needed to encode the result of the encryption (which will be binary data) as text, then you'd use base64. (Because the result of encrypting UTF-8-encoded text is not UTF-8-encoded text.)
So something like:
public static string EncryptText(string input)
{
byte[] unencryptedBytes = Encoding.UTF8.GetBytes(input);
byte[] encryptedBytes = EncryptBytes(unencryptedBytes); // Not shown here
return Convert.ToBase64String(encryptedBytes);
}
public static string DecryptText(string input)
{
byte[] encryptedBytes = Convert.FromBase64String(input);
byte[] unencryptedBytes = DecryptBytes(encryptedBytes); // Not shown here
return Encoding.UTF8.GetString(unencryptedBytes);
}

Invalid length for a Base-64 char array

I'm getting a "Invalid length for a Base-64 char array." inside of the IF(){...} are variations i have tried to get it to work. it fails in the first line without calling decrypt(...) proving it's not that functions problem. i get the same error inside with the first decrypt(...) call. the last one using the encoding.ascii... will get me inside the function, but then it fails inside the function. I'm getting the proper encrypted info from the database to string SSnum. it's value is: 4+mFeTp3tPF
try
{
string SSnum = dr.GetString(dr.GetOrdinal("Social Security"));
if (isEncrypted)
{
byte[] temp = Convert.FromBase64String(SSnum);
//SSnum = decrypt(Convert.FromBase64String(SSnum), Key, IV);
//SSnum = decrypt(Encoding.ASCII.GetBytes(SSnum), Key, IV);
}
txt_Social_Security.Text = SSnum;
}
catch { txt_Social_Security.Text = ""; }
I've been told to use the Convert.FromBase64String() and not the ASCII method...so why is it failing, how can i fix it?

Base64 data length should be multiple of 4 and with padding char '='
You can change your data as valid base64 data.
string dummyData = imgData.Trim().Replace(" ", "+");
if (dummyData.Length % 4 > 0)
dummyData = dummyData.PadRight(dummyData.Length + 4 - dummyData.Length % 4, '=');
byte[] byteArray = Convert.FromBase64String(dummyData);
https://stackoverflow.com/a/9301545/2024022
This will help you , try once.
Thanks
suribabu.

it's value is: 4+mFeTp3tPF
You are receiving this error because that value, 4+mFeTp3tPF, is in fact not valid Base64.
Is it possible you are simply missing the required padding character, as so 4+mFeTp3tPF=?

Are you certain that you have a Base64 string? Base64 is a means of encoding binary data into a string while only using standard 7-bit ASCII characters. It's not a string encoding like ASCII and has some control bytes present. You have a Base64 string if you're using Convert.ToBase64String to obtain the value (which, if you're trying to store binary data as a string, is your best bet)
Judging by your error (and your example data), I'm assuming that you do not have a Base64 string. If you need to store binary data in the database, you can either create a column using a binary type or encode the string into Base64 by using Convert.ToBase64String.
byte[] inputData = ...;
string base64String = Convert.ToBase64String(inputData);
byte[] outputData = Convert.FromBase64String(base64String);
Here, outputData should contain the same data as inputData.
If what you have is just an ASCII-encoded string, then your original practice of using System.Text.Encoding.ASCII.GetBytes() is correct, but you should change this to use a Base64 string if you can.

Are you sure that string 4+mFeTp3tPF is well-formed Base64 string?
I've tried some online services - no one could convert it.

replace
byte[] temp = Convert.FromBase64String(SSnum);
to this
var temp = UTF8Encoding.UTF8.GetBytes(SSnum);