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using System;
using System.IO;
using System.Text;
using Org.BouncyCastle.Asn1;
using Org.BouncyCastle.Asn1.X509;
using Org.BouncyCastle.Crypto;
using Org.BouncyCastle.Utilities;
using Org.BouncyCastle.X509;
namespace Org.BouncyCastle.Pkix
{
/// <summary>
/// A trust anchor or most-trusted Certification Authority (CA).
///
/// This class represents a "most-trusted CA", which is used as a trust anchor
/// for validating X.509 certification paths. A most-trusted CA includes the
/// public key of the CA, the CA's name, and any constraints upon the set of
/// paths which may be validated using this key. These parameters can be
/// specified in the form of a trusted X509Certificate or as individual
/// parameters.
/// </summary>
public class TrustAnchor
{
private readonly AsymmetricKeyParameter pubKey;
private readonly string caName;
private readonly X509Name caPrincipal;
private readonly X509Certificate trustedCert;
private byte[] ncBytes;
private NameConstraints nc;
/// <summary>
/// Creates an instance of TrustAnchor with the specified X509Certificate and
/// optional name constraints, which are intended to be used as additional
/// constraints when validating an X.509 certification path.
/// The name constraints are specified as a byte array. This byte array
/// should contain the DER encoded form of the name constraints, as they
/// would appear in the NameConstraints structure defined in RFC 2459 and
/// X.509. The ASN.1 definition of this structure appears below.
///
/// <pre>
/// NameConstraints ::= SEQUENCE {
/// permittedSubtrees [0] GeneralSubtrees OPTIONAL,
/// excludedSubtrees [1] GeneralSubtrees OPTIONAL }
///
/// GeneralSubtrees ::= SEQUENCE SIZE (1..MAX) OF GeneralSubtree
///
/// GeneralSubtree ::= SEQUENCE {
/// base GeneralName,
/// minimum [0] BaseDistance DEFAULT 0,
/// maximum [1] BaseDistance OPTIONAL }
///
/// BaseDistance ::= INTEGER (0..MAX)
///
/// GeneralName ::= CHOICE {
/// otherName [0] OtherName,
/// rfc822Name [1] IA5String,
/// dNSName [2] IA5String,
/// x400Address [3] ORAddress,
/// directoryName [4] Name,
/// ediPartyName [5] EDIPartyName,
/// uniformResourceIdentifier [6] IA5String,
/// iPAddress [7] OCTET STRING,
/// registeredID [8] OBJECT IDENTIFIER}
/// </pre>
///
/// Note that the name constraints byte array supplied is cloned to protect
/// against subsequent modifications.
/// </summary>
/// <param name="trustedCert">a trusted X509Certificate</param>
/// <param name="nameConstraints">a byte array containing the ASN.1 DER encoding of a
/// NameConstraints extension to be used for checking name
/// constraints. Only the value of the extension is included, not
/// the OID or criticality flag. Specify null to omit the
/// parameter.</param>
/// <exception cref="ArgumentNullException">if the specified X509Certificate is null</exception>
public TrustAnchor(
X509Certificate trustedCert,
byte[] nameConstraints)
{
if (trustedCert == null)
throw new ArgumentNullException("trustedCert");
this.trustedCert = trustedCert;
this.pubKey = null;
this.caName = null;
this.caPrincipal = null;
setNameConstraints(nameConstraints);
}
/// <summary>
/// Creates an instance of <c>TrustAnchor</c> where the
/// most-trusted CA is specified as an X500Principal and public key.
/// </summary>
/// <remarks>
/// <p>
/// Name constraints are an optional parameter, and are intended to be used
/// as additional constraints when validating an X.509 certification path.
/// </p><p>
/// The name constraints are specified as a byte array. This byte array
/// contains the DER encoded form of the name constraints, as they
/// would appear in the NameConstraints structure defined in RFC 2459
/// and X.509. The ASN.1 notation for this structure is supplied in the
/// documentation for the other constructors.
/// </p><p>
/// Note that the name constraints byte array supplied here is cloned to
/// protect against subsequent modifications.
/// </p>
/// </remarks>
/// <param name="caPrincipal">the name of the most-trusted CA as X509Name</param>
/// <param name="pubKey">the public key of the most-trusted CA</param>
/// <param name="nameConstraints">
/// a byte array containing the ASN.1 DER encoding of a NameConstraints extension to
/// be used for checking name constraints. Only the value of the extension is included,
/// not the OID or criticality flag. Specify <c>null</c> to omit the parameter.
/// </param>
/// <exception cref="ArgumentNullException">
/// if <c>caPrincipal</c> or <c>pubKey</c> is null
/// </exception>
public TrustAnchor(
X509Name caPrincipal,
AsymmetricKeyParameter pubKey,
byte[] nameConstraints)
{
if (caPrincipal == null)
throw new ArgumentNullException("caPrincipal");
if (pubKey == null)
throw new ArgumentNullException("pubKey");
this.trustedCert = null;
this.caPrincipal = caPrincipal;
this.caName = caPrincipal.ToString();
this.pubKey = pubKey;
setNameConstraints(nameConstraints);
}
/// <summary>
/// Creates an instance of <code>TrustAnchor</code> where the most-trusted
/// CA is specified as a distinguished name and public key. Name constraints
/// are an optional parameter, and are intended to be used as additional
/// constraints when validating an X.509 certification path.
/// <br/>
/// The name constraints are specified as a byte array. This byte array
/// contains the DER encoded form of the name constraints, as they would
/// appear in the NameConstraints structure defined in RFC 2459 and X.509.
/// </summary>
/// <param name="caName">the X.500 distinguished name of the most-trusted CA in RFC
/// 2253 string format</param>
/// <param name="pubKey">the public key of the most-trusted CA</param>
/// <param name="nameConstraints">a byte array containing the ASN.1 DER encoding of a
/// NameConstraints extension to be used for checking name
/// constraints. Only the value of the extension is included, not
/// the OID or criticality flag. Specify null to omit the
/// parameter.</param>
/// throws NullPointerException, IllegalArgumentException
public TrustAnchor(
string caName,
AsymmetricKeyParameter pubKey,
byte[] nameConstraints)
{
if (caName == null)
throw new ArgumentNullException("caName");
if (pubKey == null)
throw new ArgumentNullException("pubKey");
if (caName.Length == 0)
throw new ArgumentException("caName can not be an empty string");
this.caPrincipal = new X509Name(caName);
this.pubKey = pubKey;
this.caName = caName;
this.trustedCert = null;
setNameConstraints(nameConstraints);
}
/// <summary>
/// Returns the most-trusted CA certificate.
/// </summary>
public X509Certificate TrustedCert
{
get { return this.trustedCert; }
}
/// <summary>
/// Returns the name of the most-trusted CA as an X509Name.
/// </summary>
public X509Name CA
{
get { return this.caPrincipal; }
}
/// <summary>
/// Returns the name of the most-trusted CA in RFC 2253 string format.
/// </summary>
public string CAName
{
get { return this.caName; }
}
/// <summary>
/// Returns the public key of the most-trusted CA.
/// </summary>
public AsymmetricKeyParameter CAPublicKey
{
get { return this.pubKey; }
}
/// <summary>
/// Decode the name constraints and clone them if not null.
/// </summary>
private void setNameConstraints(
byte[] bytes)
{
if (bytes == null)
{
ncBytes = null;
nc = null;
}
else
{
ncBytes = (byte[]) bytes.Clone();
// validate DER encoding
//nc = new NameConstraintsExtension(Boolean.FALSE, bytes);
nc = NameConstraints.GetInstance(Asn1Object.FromByteArray(bytes));
}
}
public byte[] GetNameConstraints
{
get { return Arrays.Clone(ncBytes); }
}
/// <summary>
/// Returns a formatted string describing the <code>TrustAnchor</code>.
/// </summary>
/// <returns>a formatted string describing the <code>TrustAnchor</code></returns>
public override string ToString()
{
// TODO Some of the sub-objects might not implement ToString() properly
StringBuilder sb = new StringBuilder();
sb.AppendLine("[");
if (this.pubKey != null)
{
sb.Append(" Trusted CA Public Key: ").Append(this.pubKey).AppendLine();
sb.Append(" Trusted CA Issuer Name: ").Append(this.caName).AppendLine();
}
else
{
sb.Append(" Trusted CA cert: ").Append(this.TrustedCert).AppendLine();
}
if (nc != null)
{
sb.Append(" Name Constraints: ").Append(nc).AppendLine();
}
return sb.ToString();
}
}
}
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