RSASSAPSSparams.java revision e1142c149e244797ce73b0e7fad40816e447a817 
1package org.bouncycastle.asn1.pkcs;
2
3import java.math.BigInteger;
4
5import org.bouncycastle.asn1.ASN1EncodableVector;
6import org.bouncycastle.asn1.ASN1Integer;
7import org.bouncycastle.asn1.ASN1Object;
8import org.bouncycastle.asn1.ASN1Primitive;
9import org.bouncycastle.asn1.ASN1Sequence;
10import org.bouncycastle.asn1.ASN1TaggedObject;
11import org.bouncycastle.asn1.DERNull;
12import org.bouncycastle.asn1.DERSequence;
13import org.bouncycastle.asn1.DERTaggedObject;
14import org.bouncycastle.asn1.oiw.OIWObjectIdentifiers;
15import org.bouncycastle.asn1.x509.AlgorithmIdentifier;
16
17public class RSASSAPSSparams
18    extends ASN1Object
19{
20    private AlgorithmIdentifier hashAlgorithm;
21    private AlgorithmIdentifier maskGenAlgorithm;
22    private ASN1Integer          saltLength;
23    private ASN1Integer          trailerField;
24
25    public final static AlgorithmIdentifier DEFAULT_HASH_ALGORITHM = new AlgorithmIdentifier(OIWObjectIdentifiers.idSHA1, DERNull.INSTANCE);
26    public final static AlgorithmIdentifier DEFAULT_MASK_GEN_FUNCTION = new AlgorithmIdentifier(PKCSObjectIdentifiers.id_mgf1, DEFAULT_HASH_ALGORITHM);
27    public final static ASN1Integer          DEFAULT_SALT_LENGTH = new ASN1Integer(20);
28    public final static ASN1Integer          DEFAULT_TRAILER_FIELD = new ASN1Integer(1);
29
30    public static RSASSAPSSparams getInstance(
31        Object  obj)
32    {
33        if (obj instanceof RSASSAPSSparams)
34        {
35            return (RSASSAPSSparams)obj;
36        }
37        else if (obj != null)
38        {
39            return new RSASSAPSSparams(ASN1Sequence.getInstance(obj));
40        }
41
42        return null;
43    }
44
45    /**
46     * The default version
47     */
48    public RSASSAPSSparams()
49    {
50        hashAlgorithm = DEFAULT_HASH_ALGORITHM;
51        maskGenAlgorithm = DEFAULT_MASK_GEN_FUNCTION;
52        saltLength = DEFAULT_SALT_LENGTH;
53        trailerField = DEFAULT_TRAILER_FIELD;
54    }
55
56    public RSASSAPSSparams(
57        AlgorithmIdentifier hashAlgorithm,
58        AlgorithmIdentifier maskGenAlgorithm,
59        ASN1Integer          saltLength,
60        ASN1Integer          trailerField)
61    {
62        this.hashAlgorithm = hashAlgorithm;
63        this.maskGenAlgorithm = maskGenAlgorithm;
64        this.saltLength = saltLength;
65        this.trailerField = trailerField;
66    }
67
68    private RSASSAPSSparams(
69        ASN1Sequence seq)
70    {
71        hashAlgorithm = DEFAULT_HASH_ALGORITHM;
72        maskGenAlgorithm = DEFAULT_MASK_GEN_FUNCTION;
73        saltLength = DEFAULT_SALT_LENGTH;
74        trailerField = DEFAULT_TRAILER_FIELD;
75
76        for (int i = 0; i != seq.size(); i++)
77        {
78            ASN1TaggedObject    o = (ASN1TaggedObject)seq.getObjectAt(i);
79
80            switch (o.getTagNo())
81            {
82            case 0:
83                hashAlgorithm = AlgorithmIdentifier.getInstance(o, true);
84                break;
85            case 1:
86                maskGenAlgorithm = AlgorithmIdentifier.getInstance(o, true);
87                break;
88            case 2:
89                saltLength = ASN1Integer.getInstance(o, true);
90                break;
91            case 3:
92                trailerField = ASN1Integer.getInstance(o, true);
93                break;
94            default:
95                throw new IllegalArgumentException("unknown tag");
96            }
97        }
98    }
99
100    public AlgorithmIdentifier getHashAlgorithm()
101    {
102        return hashAlgorithm;
103    }
104
105    public AlgorithmIdentifier getMaskGenAlgorithm()
106    {
107        return maskGenAlgorithm;
108    }
109
110    public BigInteger getSaltLength()
111    {
112        return saltLength.getValue();
113    }
114
115    public BigInteger getTrailerField()
116    {
117        return trailerField.getValue();
118    }
119
120    /**
121     * <pre>
122     * RSASSA-PSS-params ::= SEQUENCE {
123     *   hashAlgorithm      [0] OAEP-PSSDigestAlgorithms  DEFAULT sha1,
124     *    maskGenAlgorithm   [1] PKCS1MGFAlgorithms  DEFAULT mgf1SHA1,
125     *    saltLength         [2] INTEGER  DEFAULT 20,
126     *    trailerField       [3] TrailerField  DEFAULT trailerFieldBC
127     *  }
128     *
129     * OAEP-PSSDigestAlgorithms    ALGORITHM-IDENTIFIER ::= {
130     *    { OID id-sha1 PARAMETERS NULL   }|
131     *    { OID id-sha256 PARAMETERS NULL }|
132     *    { OID id-sha384 PARAMETERS NULL }|
133     *    { OID id-sha512 PARAMETERS NULL },
134     *    ...  -- Allows for future expansion --
135     * }
136     *
137     * PKCS1MGFAlgorithms    ALGORITHM-IDENTIFIER ::= {
138     *   { OID id-mgf1 PARAMETERS OAEP-PSSDigestAlgorithms },
139     *    ...  -- Allows for future expansion --
140     * }
141     *
142     * TrailerField ::= INTEGER { trailerFieldBC(1) }
143     * </pre>
144     * @return the asn1 primitive representing the parameters.
145     */
146    public ASN1Primitive toASN1Primitive()
147    {
148        ASN1EncodableVector v = new ASN1EncodableVector();
149
150        if (!hashAlgorithm.equals(DEFAULT_HASH_ALGORITHM))
151        {
152            v.add(new DERTaggedObject(true, 0, hashAlgorithm));
153        }
154
155        if (!maskGenAlgorithm.equals(DEFAULT_MASK_GEN_FUNCTION))
156        {
157            v.add(new DERTaggedObject(true, 1, maskGenAlgorithm));
158        }
159
160        if (!saltLength.equals(DEFAULT_SALT_LENGTH))
161        {
162            v.add(new DERTaggedObject(true, 2, saltLength));
163        }
164
165        if (!trailerField.equals(DEFAULT_TRAILER_FIELD))
166        {
167            v.add(new DERTaggedObject(true, 3, trailerField));
168        }
169
170        return new DERSequence(v);
171    }
172}
173