//
// System.Security.Cryptography.X509Certificates.X509SubjectKeyIdentifierExtension
//
// Authors:
// Tim Coleman (tim@timcoleman.com)
// Sebastien Pouliot <sebastien@ximian.com>
//
// Copyright (C) Tim Coleman, 2004
// Copyright (C) 2004-2005 Novell Inc. (http://www.novell.com)
//
// Permission is hereby granted, free of charge, to any person obtaining
// a copy of this software and associated documentation files (the
// "Software"), to deal in the Software without restriction, including
// without limitation the rights to use, copy, modify, merge, publish,
// distribute, sublicense, and/or sell copies of the Software, and to
// permit persons to whom the Software is furnished to do so, subject to
// the following conditions:
//
// The above copyright notice and this permission notice shall be
// included in all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
// EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
// NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
// LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
// OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
// WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
//
#if SECURITY_DEP || MOONLIGHT
using System.Text;
using Mono.Security;
using Mono.Security.Cryptography;
namespace System.Security.Cryptography.X509Certificates{
public sealed class X509SubjectKeyIdentifierExtension : X509Extension {
internal const string oid = "2.5.29.14";
internal const string friendlyName = "Subject Key Identifier";
private byte[] _subjectKeyIdentifier;
private string _ski;
private AsnDecodeStatus _status;
// constructors
public X509SubjectKeyIdentifierExtension ()
{
_oid = new Oid (oid, friendlyName);
}
public X509SubjectKeyIdentifierExtension (AsnEncodedData encodedSubjectKeyIdentifier, bool critical)
{
// ignore the Oid provided by encodedKeyUsage (our rules!)
_oid = new Oid (oid, friendlyName);
_raw = encodedSubjectKeyIdentifier.RawData;
base.Critical = critical;
_status = Decode (this.RawData);
}
public X509SubjectKeyIdentifierExtension (byte[] subjectKeyIdentifier, bool critical)
{
if (subjectKeyIdentifier == null)
throw new ArgumentNullException ("subjectKeyIdentifier");
if (subjectKeyIdentifier.Length == 0)
throw new ArgumentException ("subjectKeyIdentifier");
_oid = new Oid (oid, friendlyName);
base.Critical = critical;
_subjectKeyIdentifier = (byte[])subjectKeyIdentifier.Clone ();
RawData = Encode ();
}
public X509SubjectKeyIdentifierExtension (string subjectKeyIdentifier, bool critical)
{
if (subjectKeyIdentifier == null)
throw new ArgumentNullException ("subjectKeyIdentifier");
if (subjectKeyIdentifier.Length < 2)
throw new ArgumentException ("subjectKeyIdentifier");
_oid = new Oid (oid, friendlyName);
base.Critical = critical;
_subjectKeyIdentifier = FromHex (subjectKeyIdentifier);
RawData = Encode ();
}
public X509SubjectKeyIdentifierExtension (PublicKey key, bool critical)
: this (key, X509SubjectKeyIdentifierHashAlgorithm.Sha1, critical)
{
}
public X509SubjectKeyIdentifierExtension (PublicKey key, X509SubjectKeyIdentifierHashAlgorithm algorithm, bool critical)
{
if (key == null)
throw new ArgumentNullException ("key");
byte[] pkraw = key.EncodedKeyValue.RawData;
// compute SKI
switch (algorithm) {
// hash of the public key, excluding Tag, Length and unused bits values
case X509SubjectKeyIdentifierHashAlgorithm.Sha1:
_subjectKeyIdentifier = SHA1.Create ().ComputeHash (pkraw);
break;
// 0100 bit pattern followed by the 60 last bit of the hash
case X509SubjectKeyIdentifierHashAlgorithm.ShortSha1:
byte[] hash = SHA1.Create ().ComputeHash (pkraw);
_subjectKeyIdentifier = new byte [8];
Buffer.BlockCopy (hash, 12, _subjectKeyIdentifier, 0, 8);
_subjectKeyIdentifier [0] = (byte) (0x40 | (_subjectKeyIdentifier [0] & 0x0F));
break;
// hash of the public key, including Tag, Length and unused bits values
case X509SubjectKeyIdentifierHashAlgorithm.CapiSha1:
// CryptoAPI does that hash on the complete subjectPublicKeyInfo (unlike PKIX)
// http://groups.google.ca/groups?selm=e7RqM%24plCHA.1488%40tkmsftngp02&oe=UTF-8&output=gplain
ASN1 subjectPublicKeyInfo = new ASN1 (0x30);
ASN1 algo = subjectPublicKeyInfo.Add (new ASN1 (0x30));
algo.Add (new ASN1 (CryptoConfig.EncodeOID (key.Oid.Value)));
algo.Add (new ASN1 (key.EncodedParameters.RawData));
// add an extra byte for the unused bits (none)
byte[] full = new byte [pkraw.Length + 1];
Buffer.BlockCopy (pkraw, 0, full, 1, pkraw.Length);
subjectPublicKeyInfo.Add (new ASN1 (0x03, full));
_subjectKeyIdentifier = SHA1.Create ().ComputeHash (subjectPublicKeyInfo.GetBytes ());
break;
default:
throw new ArgumentException ("algorithm");
}
_oid = new Oid (oid, friendlyName);
base.Critical = critical;
RawData = Encode ();
}
// properties
public string SubjectKeyIdentifier {
get {
switch (_status) {
case AsnDecodeStatus.Ok:
case AsnDecodeStatus.InformationNotAvailable:
if (_subjectKeyIdentifier != null)
_ski = CryptoConvert.ToHex (_subjectKeyIdentifier);
return _ski;
default:
throw new CryptographicException ("Badly encoded extension.");
}
}
}
// methods
public override void CopyFrom (AsnEncodedData encodedData)
{
if (encodedData == null)
throw new ArgumentNullException ("encodedData");
X509Extension ex = (encodedData as X509Extension);
if (ex == null)
throw new ArgumentException (Locale.GetText ("Wrong type."), "encodedData");
if (ex._oid == null)
_oid = new Oid (oid, friendlyName);
else
_oid = new Oid (ex._oid);
RawData = ex.RawData;
base.Critical = ex.Critical;
// and we deal with the rest later
_status = Decode (this.RawData);
}
// internal
static internal byte FromHexChar (char c)
{
if ((c >= 'a') && (c <= 'f'))
return (byte) (c - 'a' + 10);
if ((c >= 'A') && (c <= 'F'))
return (byte) (c - 'A' + 10);
if ((c >= '0') && (c <= '9'))
return (byte) (c - '0');
return 255; // F
}
static internal byte FromHexChars (char c1, char c2)
{
byte result = FromHexChar (c1);
if (result < 255)
result = (byte) ((result << 4) | FromHexChar (c2));
return result;
}
static internal byte[] FromHex (string hex)
{
// here we can't use CryptoConvert.FromHex because we
// must convert any *illegal* (non hex) 2 characters
// to 'FF' and ignore last char on odd length
if (hex == null)
return null;
int length = hex.Length >> 1;
byte[] result = new byte [length]; // + (odd ? 1 : 0)];
int n = 0;
int i = 0;
while (n < length) {
result [n++] = FromHexChars (hex [i++], hex [i++]);
}
return result;
}
internal AsnDecodeStatus Decode (byte[] extension)
{
if ((extension == null) || (extension.Length == 0))
return AsnDecodeStatus.BadAsn;
_ski = String.Empty;
if (extension [0] != 0x04)
return AsnDecodeStatus.BadTag;
if (extension.Length == 2)
return AsnDecodeStatus.InformationNotAvailable;
if (extension.Length < 3)
return AsnDecodeStatus.BadLength;
try {
ASN1 ex = new ASN1 (extension);
_subjectKeyIdentifier = ex.Value;
}
catch {
return AsnDecodeStatus.BadAsn;
}
return AsnDecodeStatus.Ok;
}
internal byte[] Encode ()
{
ASN1 ex = new ASN1 (0x04, _subjectKeyIdentifier);
return ex.GetBytes ();
}
internal override string ToString (bool multiLine)
{
switch (_status) {
case AsnDecodeStatus.BadAsn:
return String.Empty;
case AsnDecodeStatus.BadTag:
case AsnDecodeStatus.BadLength:
return FormatUnkownData (_raw);
case AsnDecodeStatus.InformationNotAvailable:
return "Information Not Available";
}
if (_oid.Value != oid)
return String.Format ("Unknown Key Usage ({0})", _oid.Value);
StringBuilder sb = new StringBuilder ();
for (int i=0; i < _subjectKeyIdentifier.Length; i++) {
sb.Append (_subjectKeyIdentifier [i].ToString ("x2"));
if (i != _subjectKeyIdentifier.Length - 1)
sb.Append (" ");
}
if (multiLine)
sb.Append (Environment.NewLine);
return sb.ToString ();
}
}
}
#endif
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