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//
// KeyUsageExtension.cs: Handles X.509 KeyUsage extensions.
//
// Author:
// Sebastien Pouliot <sebastien@ximian.com>
//
// (C) 2003 Motus Technologies Inc. (http://www.motus.com)
// (C) 2004 Novell (http://www.novell.com)
//
using System;
using System.Globalization;
using System.Text;
using Mono.Security;
using Mono.Security.X509;
namespace Mono.Security.X509.Extensions {
/*
* id-ce-keyUsage OBJECT IDENTIFIER ::= { id-ce 15 }
*
* KeyUsage ::= BIT STRING {
* digitalSignature (0),
* nonRepudiation (1),
* keyEncipherment (2),
* dataEncipherment (3),
* keyAgreement (4),
* keyCertSign (5),
* cRLSign (6),
* encipherOnly (7),
* decipherOnly (8)
* }
*/
// note: because nothing is simple in ASN.1 bits are reversed
[Flags]
#if INSIDE_CORLIB
internal
#else
public
#endif
enum KeyUsages {
digitalSignature = 0x80,
nonRepudiation = 0x40,
keyEncipherment = 0x20,
dataEncipherment = 0x10,
keyAgreement = 0x08,
keyCertSign = 0x04,
cRLSign = 0x02,
encipherOnly = 0x01,
decipherOnly = 0x800,
none = 0x0
}
#if INSIDE_CORLIB
internal
#else
public
#endif
class KeyUsageExtension : X509Extension {
private int kubits;
public KeyUsageExtension (ASN1 asn1) : base (asn1) {}
public KeyUsageExtension (X509Extension extension) : base (extension) {}
protected override void Decode ()
{
ASN1 bitString = new ASN1 (extnValue.Value);
if (bitString.Tag != 0x03)
throw new ArgumentException ("Invalid KeyUsage extension");
int i = 1; // byte zero has the number of unused bits (ASN1's BITSTRING)
while (i < bitString.Value.Length)
kubits = (kubits << 8) + bitString.Value [i++];
}
public override string Name {
get { return "Key Usage"; }
}
public bool Support (KeyUsages usage)
{
int x = Convert.ToInt32 (usage, CultureInfo.InvariantCulture);
return ((x & kubits) == x);
}
public override string ToString ()
{
const string separator = " , ";
StringBuilder sb = new StringBuilder ();
if (Support (KeyUsages.digitalSignature))
sb.Append ("Digital Signature");
if (Support (KeyUsages.nonRepudiation)) {
if (sb.Length > 0)
sb.Append (separator);
sb.Append ("Non-Repudiation");
}
if (Support (KeyUsages.keyEncipherment)) {
if (sb.Length > 0)
sb.Append (separator);
sb.Append ("Key Encipherment");
}
if (Support (KeyUsages.dataEncipherment)) {
if (sb.Length > 0)
sb.Append (separator);
sb.Append ("Data Encipherment");
}
if (Support (KeyUsages.keyAgreement)) {
if (sb.Length > 0)
sb.Append (separator);
sb.Append ("Key Agreement");
}
if (Support (KeyUsages.keyCertSign)) {
if (sb.Length > 0)
sb.Append (separator);
sb.Append ("Certificate Signing");
}
if (Support (KeyUsages.cRLSign)) {
if (sb.Length > 0)
sb.Append (separator);
sb.Append ("CRL Signing");
}
if (Support (KeyUsages.encipherOnly)) {
if (sb.Length > 0)
sb.Append (separator);
sb.Append ("Encipher Only "); // ???
}
if (Support (KeyUsages.decipherOnly)) {
if (sb.Length > 0)
sb.Append (separator);
sb.Append ("Decipher Only"); // ???
}
sb.Append ("(");
sb.Append (kubits.ToString ("X2", CultureInfo.InvariantCulture));
sb.Append (")");
sb.Append (Environment.NewLine);
return sb.ToString ();
}
}
}
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