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c#cryptographyarraysx509certificate
Petey B
Petey B

Reputation: 11569

X509Certificate Serial Number as Byte Array? C#

What would be the best way of converting a serial number from an X509certifiacte2 to a byte array (for storage) and back?

Upvotes: 1

Views: 3422

Answers (4)

Yola
Yola

Reputation: 19033

You can use X509Certificate.GetSerialNumber. This method is accessible from X509Certificate2 as well.

Please, be wary about bytes order:

Returns the serial number of the X.509v3 certificate as an array of bytes in little-endian order.

Upvotes: 0

Petey B
Petey B

Reputation: 11569

public static String byteArrayToHex(byte[] data)
        {
            return BitConverter.ToString(data).Replace("-", string.Empty);
        }

Upvotes: 0

dtb
dtb

Reputation: 217293

Here are two extension methods to convert a hexadecimal string to a byte array and back:

static byte[] ParseAsBytes(static string s)
{
    return Enumerable.Range(0, s.Length / 2)
                     .Select(i => byte.Parse(s.Substring(i * 2, 2), 
                                             NumberStyles.AllowHexSpecifier))
                     .ToArray();
}

static string ToHexString(this byte[] buffer)
{
    return string.Concat(buffer.Select(i => i.ToString("X2")));
}

Usage:

var input = "0001020304050607";

var bytes = input.ParseAsBytes();
// bytes == new byte[] { 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07 }

var result = bytes.ToHexString();
// result == "0001020304050607"

(For more efficient implementations, have a look the code of the internal System.Security.Util.Hex class using a tool like Reflector. These are used by the SerialNumber property to convert an internal byte[] field in the X509Certificate class to a hexadecimal string.)

Upvotes: 1

The Moof
The Moof

Reputation: 804

System.Text.Encoding handles converting strings to/from byte array. You should be able to do the following (assuming you're using ASCII for text encoding):

byte[] serial = System.Text.Encoding.ASCII.GetBytes(x509_cert.SerialNumber);

and to get the byte[] serial back into a string:

string x509_serial = System.Text.Encoding.ASCII.GetString(serial);

Upvotes: 0

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