1package org.bouncycastle.asn1.x509;
2
3import org.bouncycastle.asn1.ASN1Object;
4import org.bouncycastle.asn1.ASN1Primitive;
5import org.bouncycastle.asn1.DERBitString;
6
7/**
8 * The KeyUsage object.
9 * <pre>
10 *    id-ce-keyUsage OBJECT IDENTIFIER ::=  { id-ce 15 }
11 *
12 *    KeyUsage ::= BIT STRING {
13 *         digitalSignature        (0),
14 *         nonRepudiation          (1),
15 *         keyEncipherment         (2),
16 *         dataEncipherment        (3),
17 *         keyAgreement            (4),
18 *         keyCertSign             (5),
19 *         cRLSign                 (6),
20 *         encipherOnly            (7),
21 *         decipherOnly            (8) }
22 * </pre>
23 */
24public class KeyUsage
25    extends ASN1Object
26{
27    public static final int        digitalSignature = (1 << 7);
28    public static final int        nonRepudiation   = (1 << 6);
29    public static final int        keyEncipherment  = (1 << 5);
30    public static final int        dataEncipherment = (1 << 4);
31    public static final int        keyAgreement     = (1 << 3);
32    public static final int        keyCertSign      = (1 << 2);
33    public static final int        cRLSign          = (1 << 1);
34    public static final int        encipherOnly     = (1 << 0);
35    public static final int        decipherOnly     = (1 << 15);
36
37    private DERBitString bitString;
38
39    public static KeyUsage getInstance(Object obj)   // needs to be DERBitString for other VMs
40    {
41        if (obj instanceof KeyUsage)
42        {
43            return (KeyUsage)obj;
44        }
45        else if (obj != null)
46        {
47            return new KeyUsage(DERBitString.getInstance(obj));
48        }
49
50        return null;
51    }
52
53    public static KeyUsage fromExtensions(Extensions extensions)
54    {
55        return KeyUsage.getInstance(extensions.getExtensionParsedValue(Extension.keyUsage));
56    }
57
58    /**
59     * Basic constructor.
60     *
61     * @param usage - the bitwise OR of the Key Usage flags giving the
62     * allowed uses for the key.
63     * e.g. (KeyUsage.keyEncipherment | KeyUsage.dataEncipherment)
64     */
65    public KeyUsage(
66        int usage)
67    {
68        this.bitString = new DERBitString(usage);
69    }
70
71    private KeyUsage(
72        DERBitString bitString)
73    {
74        this.bitString = bitString;
75    }
76
77    /**
78     * Return true if a given usage bit is set, false otherwise.
79     *
80     * @param usages combination of usage flags.
81     * @return true if all bits are set, false otherwise.
82     */
83    public boolean hasUsages(int usages)
84    {
85        return (bitString.intValue() & usages) == usages;
86    }
87
88    public byte[] getBytes()
89    {
90        return bitString.getBytes();
91    }
92
93    public int getPadBits()
94    {
95        return bitString.getPadBits();
96    }
97
98    public String toString()
99    {
100        byte[] data = bitString.getBytes();
101
102        if (data.length == 1)
103        {
104            return "KeyUsage: 0x" + Integer.toHexString(data[0] & 0xff);
105        }
106        return "KeyUsage: 0x" + Integer.toHexString((data[1] & 0xff) << 8 | (data[0] & 0xff));
107    }
108
109    public ASN1Primitive toASN1Primitive()
110    {
111        return bitString;
112    }
113}
114