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package sun.security.x509;

import java.io.IOException;
import java.io.OutputStream;
import java.util.Enumeration;

import sun.security.util.*;

Represent the Subject Key Identifier Extension. This extension, if present, provides a means of identifying the particular public key used in an application. This extension by default is marked non-critical.

Extensions are addiitonal attributes which can be inserted in a X509 v3 certificate. For example a "Driving License Certificate" could have the driving license number as a extension.

Extensions are represented as a sequence of the extension identifier (Object Identifier), a boolean flag stating whether the extension is to be treated as being critical and the extension value itself (this is again a DER encoding of the extension value).

Author:Amit Kapoor, Hemma Prafullchandra
See Also:
/** * Represent the Subject Key Identifier Extension. * * This extension, if present, provides a means of identifying the particular * public key used in an application. This extension by default is marked * non-critical. * * <p>Extensions are addiitonal attributes which can be inserted in a X509 * v3 certificate. For example a "Driving License Certificate" could have * the driving license number as a extension. * * <p>Extensions are represented as a sequence of the extension identifier * (Object Identifier), a boolean flag stating whether the extension is to * be treated as being critical and the extension value itself (this is again * a DER encoding of the extension value). * * @author Amit Kapoor * @author Hemma Prafullchandra * @see Extension * @see CertAttrSet */
public class SubjectKeyIdentifierExtension extends Extension implements CertAttrSet<String> {
Identifier for this attribute, to be used with the get, set, delete methods of Certificate, x509 type.
/** * Identifier for this attribute, to be used with the * get, set, delete methods of Certificate, x509 type. */
public static final String IDENT = "x509.info.extensions.SubjectKeyIdentifier";
Attribute names.
/** * Attribute names. */
public static final String NAME = "SubjectKeyIdentifier"; public static final String KEY_ID = "key_id"; // Private data member private KeyIdentifier id = null; // Encode this extension value private void encodeThis() throws IOException { if (id == null) { this.extensionValue = null; return; } DerOutputStream os = new DerOutputStream(); id.encode(os); this.extensionValue = os.toByteArray(); }
Create a SubjectKeyIdentifierExtension with the passed octet string. The criticality is set to False.
Params:
  • octetString – the octet string identifying the key identifier.
/** * Create a SubjectKeyIdentifierExtension with the passed octet string. * The criticality is set to False. * @param octetString the octet string identifying the key identifier. */
public SubjectKeyIdentifierExtension(byte[] octetString) throws IOException { id = new KeyIdentifier(octetString); this.extensionId = PKIXExtensions.SubjectKey_Id; this.critical = false; encodeThis(); }
Create the extension from the passed DER encoded value.
Params:
  • critical – true if the extension is to be treated as critical.
  • value – an array of DER encoded bytes of the actual value.
Throws:
/** * Create the extension from the passed DER encoded value. * * @param critical true if the extension is to be treated as critical. * @param value an array of DER encoded bytes of the actual value. * @exception ClassCastException if value is not an array of bytes * @exception IOException on error. */
public SubjectKeyIdentifierExtension(Boolean critical, Object value) throws IOException { this.extensionId = PKIXExtensions.SubjectKey_Id; this.critical = critical.booleanValue(); this.extensionValue = (byte[]) value; DerValue val = new DerValue(this.extensionValue); this.id = new KeyIdentifier(val); }
Returns a printable representation.
/** * Returns a printable representation. */
public String toString() { return super.toString() + "SubjectKeyIdentifier [\n" + String.valueOf(id) + "]\n"; }
Write the extension to the OutputStream.
Params:
  • out – the OutputStream to write the extension to.
Throws:
/** * Write the extension to the OutputStream. * * @param out the OutputStream to write the extension to. * @exception IOException on encoding errors. */
public void encode(OutputStream out) throws IOException { DerOutputStream tmp = new DerOutputStream(); if (extensionValue == null) { extensionId = PKIXExtensions.SubjectKey_Id; critical = false; encodeThis(); } super.encode(tmp); out.write(tmp.toByteArray()); }
Set the attribute value.
/** * Set the attribute value. */
public void set(String name, Object obj) throws IOException { if (name.equalsIgnoreCase(KEY_ID)) { if (!(obj instanceof KeyIdentifier)) { throw new IOException("Attribute value should be of" + " type KeyIdentifier."); } id = (KeyIdentifier)obj; } else { throw new IOException("Attribute name not recognized by " + "CertAttrSet:SubjectKeyIdentifierExtension."); } encodeThis(); }
Get the attribute value.
/** * Get the attribute value. */
public KeyIdentifier get(String name) throws IOException { if (name.equalsIgnoreCase(KEY_ID)) { return (id); } else { throw new IOException("Attribute name not recognized by " + "CertAttrSet:SubjectKeyIdentifierExtension."); } }
Delete the attribute value.
/** * Delete the attribute value. */
public void delete(String name) throws IOException { if (name.equalsIgnoreCase(KEY_ID)) { id = null; } else { throw new IOException("Attribute name not recognized by " + "CertAttrSet:SubjectKeyIdentifierExtension."); } encodeThis(); }
Return an enumeration of names of attributes existing within this attribute.
/** * Return an enumeration of names of attributes existing within this * attribute. */
public Enumeration<String> getElements() { AttributeNameEnumeration elements = new AttributeNameEnumeration(); elements.addElement(KEY_ID); return (elements.elements()); }
Return the name of this attribute.
/** * Return the name of this attribute. */
public String getName() { return (NAME); } }