1/*
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3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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7 * published by the Free Software Foundation.  Oracle designates this
8 * particular file as subject to the "Classpath" exception as provided
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10 *
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12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
14 * version 2 for more details (a copy is included in the LICENSE file that
15 * accompanied this code).
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24 */
25
26package javax.crypto;
27
28import java.security.Key;
29import java.security.AlgorithmParameters;
30import java.security.InvalidKeyException;
31import java.security.InvalidAlgorithmParameterException;
32import java.security.spec.AlgorithmParameterSpec;
33
34/**
35 * This class defines the <i>Service Provider Interface</i> (<b>SPI</b>)
36 * for the <code>ExemptionMechanism</code> class.
37 * All the abstract methods in this class must be implemented by each
38 * cryptographic service provider who wishes to supply the implementation
39 * of a particular exemption mechanism.
40 *
41 * @author Sharon Liu
42 *
43 * @since 1.4
44 */
45
46public abstract class ExemptionMechanismSpi {
47
48    /**
49     * Returns the length in bytes that an output buffer would need to be in
50     * order to hold the result of the next
51     * {@link #engineGenExemptionBlob(byte[], int) engineGenExemptionBlob}
52     * operation, given the input length <code>inputLen</code> (in bytes).
53     *
54     * <p>The actual output length of the next
55     * {@link #engineGenExemptionBlob(byte[], int) engineGenExemptionBlob}
56     * call may be smaller than the length returned by this method.
57     *
58     * @param inputLen the input length (in bytes)
59     *
60     * @return the required output buffer size (in bytes)
61     */
62    protected abstract int engineGetOutputSize(int inputLen);
63
64    /**
65     * Initializes this exemption mechanism with a key.
66     *
67     * <p>If this exemption mechanism requires any algorithm parameters
68     * that cannot be derived from the given <code>key</code>, the underlying
69     * exemption mechanism implementation is supposed to generate the required
70     * parameters itself (using provider-specific default values); in the case
71     * that algorithm parameters must be specified by the caller, an
72     * <code>InvalidKeyException</code> is raised.
73     *
74     * @param key the key for this exemption mechanism
75     *
76     * @exception InvalidKeyException if the given key is inappropriate for
77     * this exemption mechanism.
78     * @exception ExemptionMechanismException if problem(s) encountered in the
79     * process of initializing.
80     */
81    protected abstract void engineInit(Key key)
82    throws InvalidKeyException, ExemptionMechanismException;
83
84    /**
85     * Initializes this exemption mechanism with a key and a set of algorithm
86     * parameters.
87     *
88     * <p>If this exemption mechanism requires any algorithm parameters and
89     * <code>params</code> is null, the underlying exemption mechanism
90     * implementation is supposed to generate the required parameters
91     * itself (using provider-specific default values); in the case that
92     * algorithm parameters must be specified by the caller, an
93     * <code>InvalidAlgorithmParameterException</code> is raised.
94     *
95     * @param key the key for this exemption mechanism
96     * @param params the algorithm parameters
97     *
98     * @exception InvalidKeyException if the given key is inappropriate for
99     * this exemption mechanism.
100     * @exception InvalidAlgorithmParameterException if the given algorithm
101     * parameters are inappropriate for this exemption mechanism.
102     * @exception ExemptionMechanismException if problem(s) encountered in the
103     * process of initializing.
104     */
105    protected abstract void engineInit(Key key, AlgorithmParameterSpec params)
106    throws InvalidKeyException, InvalidAlgorithmParameterException,
107    ExemptionMechanismException;
108
109    /**
110     * Initializes this exemption mechanism with a key and a set of algorithm
111     * parameters.
112     *
113     * <p>If this exemption mechanism requires any algorithm parameters
114     * and <code>params</code> is null, the underlying exemption mechanism
115     * implementation is supposed to generate the required parameters
116     * itself (using provider-specific default values); in the case that
117     * algorithm parameters must be specified by the caller, an
118     * <code>InvalidAlgorithmParameterException</code> is raised.
119     *
120     * @param key the key for this exemption mechanism
121     * @param params the algorithm parameters
122     *
123     * @exception InvalidKeyException if the given key is inappropriate for
124     * this exemption mechanism.
125     * @exception InvalidAlgorithmParameterException if the given algorithm
126     * parameters are inappropriate for this exemption mechanism.
127     * @exception ExemptionMechanismException if problem(s) encountered in the
128     * process of initializing.
129     */
130    protected abstract void engineInit(Key key, AlgorithmParameters params)
131    throws InvalidKeyException, InvalidAlgorithmParameterException,
132    ExemptionMechanismException;
133
134    /**
135     * Generates the exemption mechanism key blob.
136     *
137     * @return the new buffer with the result key blob.
138     *
139     * @exception ExemptionMechanismException if problem(s) encountered in the
140     * process of generating.
141     */
142    protected abstract byte[] engineGenExemptionBlob()
143        throws ExemptionMechanismException;
144
145    /**
146     * Generates the exemption mechanism key blob, and stores the result in
147     * the <code>output</code> buffer, starting at <code>outputOffset</code>
148     * inclusive.
149     *
150     * <p>If the <code>output</code> buffer is too small to hold the result,
151     * a <code>ShortBufferException</code> is thrown. In this case, repeat this
152     * call with a larger output buffer. Use
153     * {@link #engineGetOutputSize(int) engineGetOutputSize} to determine
154     * how big the output buffer should be.
155     *
156     * @param output the buffer for the result
157     * @param outputOffset the offset in <code>output</code> where the result
158     * is stored
159     *
160     * @return the number of bytes stored in <code>output</code>
161     *
162     * @exception ShortBufferException if the given output buffer is too small
163     * to hold the result.
164     * @exception ExemptionMechanismException if problem(s) encountered in the
165     * process of generating.
166     */
167    protected abstract int engineGenExemptionBlob
168    (byte[] output, int outputOffset)
169        throws ShortBufferException, ExemptionMechanismException;
170}
171