SubjectKeyIdentifier.java revision e6bf3e8dfa2804891a82075cb469b736321b4827 
1package org.bouncycastle.asn1.x509;
2
3import org.bouncycastle.asn1.ASN1Object;
4import org.bouncycastle.asn1.ASN1OctetString;
5import org.bouncycastle.asn1.ASN1Primitive;
6import org.bouncycastle.asn1.ASN1TaggedObject;
7import org.bouncycastle.asn1.DEROctetString;
8import org.bouncycastle.crypto.Digest;
9// BEGIN android-changed
10import org.bouncycastle.crypto.digests.AndroidDigestFactory;
11// END android-changed
12
13/**
14 * The SubjectKeyIdentifier object.
15 * <pre>
16 * SubjectKeyIdentifier::= OCTET STRING
17 * </pre>
18 */
19public class SubjectKeyIdentifier
20    extends ASN1Object
21{
22    private byte[] keyidentifier;
23
24    public static SubjectKeyIdentifier getInstance(
25        ASN1TaggedObject obj,
26        boolean          explicit)
27    {
28        return getInstance(ASN1OctetString.getInstance(obj, explicit));
29    }
30
31    public static SubjectKeyIdentifier getInstance(
32        Object obj)
33    {
34        if (obj instanceof SubjectKeyIdentifier)
35        {
36            return (SubjectKeyIdentifier)obj;
37        }
38        else if (obj != null)
39        {
40            return new SubjectKeyIdentifier(ASN1OctetString.getInstance(obj));
41        }
42
43        return null;
44    }
45
46    public SubjectKeyIdentifier(
47        byte[] keyid)
48    {
49        this.keyidentifier = keyid;
50    }
51
52    protected SubjectKeyIdentifier(
53        ASN1OctetString keyid)
54    {
55        this.keyidentifier = keyid.getOctets();
56    }
57
58    public byte[] getKeyIdentifier()
59    {
60        return keyidentifier;
61    }
62
63    public ASN1Primitive toASN1Primitive()
64    {
65        return new DEROctetString(keyidentifier);
66    }
67
68
69    /**
70     * Calculates the keyidentifier using a SHA1 hash over the BIT STRING
71     * from SubjectPublicKeyInfo as defined in RFC3280.
72     *
73     * @param spki the subject public key info.
74     * @deprecated
75     */
76    public SubjectKeyIdentifier(
77        SubjectPublicKeyInfo    spki)
78    {
79        this.keyidentifier = getDigest(spki);
80    }
81
82    /**
83     * Return a RFC 3280 type 1 key identifier. As in:
84     * <pre>
85     * (1) The keyIdentifier is composed of the 160-bit SHA-1 hash of the
86     * value of the BIT STRING subjectPublicKey (excluding the tag,
87     * length, and number of unused bits).
88     * </pre>
89     * @param keyInfo the key info object containing the subjectPublicKey field.
90     * @return the key identifier.
91     * @deprecated use org.bouncycastle.cert.X509ExtensionUtils.createSubjectKeyIdentifier
92     */
93    public static SubjectKeyIdentifier createSHA1KeyIdentifier(SubjectPublicKeyInfo keyInfo)
94    {
95        return new SubjectKeyIdentifier(keyInfo);
96    }
97
98    /**
99     * Return a RFC 3280 type 2 key identifier. As in:
100     * <pre>
101     * (2) The keyIdentifier is composed of a four bit type field with
102     * the value 0100 followed by the least significant 60 bits of the
103     * SHA-1 hash of the value of the BIT STRING subjectPublicKey.
104     * </pre>
105     * @param keyInfo the key info object containing the subjectPublicKey field.
106     * @return the key identifier.
107     * @deprecated use org.bouncycastle.cert.X509ExtensionUtils.createTruncatedSubjectKeyIdentifier
108     */
109    public static SubjectKeyIdentifier createTruncatedSHA1KeyIdentifier(SubjectPublicKeyInfo keyInfo)
110    {
111        byte[] dig = getDigest(keyInfo);
112        byte[] id = new byte[8];
113
114        System.arraycopy(dig, dig.length - 8, id, 0, id.length);
115
116        id[0] &= 0x0f;
117        id[0] |= 0x40;
118
119        return new SubjectKeyIdentifier(id);
120    }
121
122    private static byte[] getDigest(SubjectPublicKeyInfo spki)
123    {
124        // BEGIN android-changed
125        Digest digest = AndroidDigestFactory.getSHA1();
126        // END android-changed
127        byte[]  resBuf = new byte[digest.getDigestSize()];
128
129        byte[] bytes = spki.getPublicKeyData().getBytes();
130        digest.update(bytes, 0, bytes.length);
131        digest.doFinal(resBuf, 0);
132        return resBuf;
133    }
134}
135