KeyFlag.java

package com.wesabe.grendel.openpgp;

import java.util.Set;

import com.google.common.collect.ImmutableSet;
import com.wesabe.grendel.util.IntegerEquivalent;

/**
 * Flags for OpenPGP keys.
 * 
 * @author coda
 * @see <a href="http://www.ietf.org/rfc/rfc4880.txt">Section 5.2.3.21, RFC 4880</a>
 */
public enum KeyFlag implements IntegerEquivalent {
	// org.bouncycastle.openpgp.PGPKeyFlags is incomplete, and thus not
	// referenced here.
	
	/**
	 * Indicates that the key can be used to certify other keys.
	 */
	CERTIFICATION(			0x01,			"certifying other keys"),
	
	/**
	 * Indicates that the key can be used to sign other keys.
	 */
	SIGNING(				0x02,			"signing data"),
	
	/**
	 * Indicates that the key can be used to encrypt communications and storage.
	 * 
	 * <b>N.B.:</b> This includes both {@code 0x04}—"this key may be used to
	 * encrypt communications"—and {@code 0x08}—"this key may be used to encrypt
	 * storage."
	 */
	ENCRYPTION(				0x04 | 0x08,	"encrypting data"),
	
	/**
	 * Indicates that the key may be split via a secret-sharing mechanism.
	 */
	SPLIT(					0x10,			"may be split via secret-sharing mechanism"),
	
	/**
	 * Indicates that the key can be used for authentication.
	 */
	AUTHENTICATION(			0x20,			"authentication"),
	
	/**
	 * Indicates that the private components of the key may be in the possession
	 * of more than one person.
	 */
	SHARED(					0x80,			"may be in the possession of more than one person");
	
	/**
	 * The default key flags for a master key.
	 */
	public static final Set<KeyFlag> MASTER_KEY_DEFAULTS =
		ImmutableSet.of(SIGNING, AUTHENTICATION, SPLIT);
	
	/**
	 * The default key flags for a sub key.
	 */
	public static final Set<KeyFlag> SUB_KEY_DEFAULTS =
		ImmutableSet.of(ENCRYPTION, SPLIT);
	
	private final String name;
	private final int value;
	
	private KeyFlag(int value, String name) {
		this.name = name;
		this.value = value;
	}
	
	@Override
	public int toInteger() {
		return value;
	}
	
	@Override
	public String toString() {
		return name;
	}
}