1package org.bouncycastle.crypto.modes;
2
3import org.bouncycastle.crypto.BlockCipher;
4import org.bouncycastle.crypto.CipherParameters;
5import org.bouncycastle.crypto.DataLengthException;
6import org.bouncycastle.crypto.InvalidCipherTextException;
7
8/**
9 * A block cipher mode that includes authenticated encryption with a streaming mode and optional associated data.
10 * <p>
11 * Implementations of this interface may operate in a packet mode (where all input data is buffered and
12 * processed dugin the call to {@link #doFinal(byte[], int)}), or in a streaming mode (where output data is
13 * incrementally produced with each call to {@link #processByte(byte, byte[], int)} or
14 * {@link #processBytes(byte[], int, int, byte[], int)}.
15 * </p>
16 * This is important to consider during decryption: in a streaming mode, unauthenticated plaintext data
17 * may be output prior to the call to {@link #doFinal(byte[], int)} that results in an authentication
18 * failure. The higher level protocol utilising this cipher must ensure the plaintext data is handled
19 * appropriately until the end of data is reached and the entire ciphertext is authenticated.
20 * @see org.bouncycastle.crypto.params.AEADParameters
21 */
22public interface AEADBlockCipher
23{
24    /**
25     * initialise the underlying cipher. Parameter can either be an AEADParameters or a ParametersWithIV object.
26     *
27     * @param forEncryption true if we are setting up for encryption, false otherwise.
28     * @param params the necessary parameters for the underlying cipher to be initialised.
29     * @exception IllegalArgumentException if the params argument is inappropriate.
30     */
31    public void init(boolean forEncryption, CipherParameters params)
32        throws IllegalArgumentException;
33
34    /**
35     * Return the name of the algorithm.
36     *
37     * @return the algorithm name.
38     */
39    public String getAlgorithmName();
40
41    /**
42     * return the cipher this object wraps.
43     *
44     * @return the cipher this object wraps.
45     */
46    public BlockCipher getUnderlyingCipher();
47
48    /**
49     * Add a single byte to the associated data check.
50     * <br>If the implementation supports it, this will be an online operation and will not retain the associated data.
51     *
52     * @param in the byte to be processed.
53     */
54    public void processAADByte(byte in);
55
56    /**
57     * Add a sequence of bytes to the associated data check.
58     * <br>If the implementation supports it, this will be an online operation and will not retain the associated data.
59     *
60     * @param in the input byte array.
61     * @param inOff the offset into the in array where the data to be processed starts.
62     * @param len the number of bytes to be processed.
63     */
64    public void processAADBytes(byte[] in, int inOff, int len);
65
66    /**
67     * encrypt/decrypt a single byte.
68     *
69     * @param in the byte to be processed.
70     * @param out the output buffer the processed byte goes into.
71     * @param outOff the offset into the output byte array the processed data starts at.
72     * @return the number of bytes written to out.
73     * @exception DataLengthException if the output buffer is too small.
74     */
75    public int processByte(byte in, byte[] out, int outOff)
76        throws DataLengthException;
77
78    /**
79     * process a block of bytes from in putting the result into out.
80     *
81     * @param in the input byte array.
82     * @param inOff the offset into the in array where the data to be processed starts.
83     * @param len the number of bytes to be processed.
84     * @param out the output buffer the processed bytes go into.
85     * @param outOff the offset into the output byte array the processed data starts at.
86     * @return the number of bytes written to out.
87     * @exception DataLengthException if the output buffer is too small.
88     */
89    public int processBytes(byte[] in, int inOff, int len, byte[] out, int outOff)
90        throws DataLengthException;
91
92    /**
93     * Finish the operation either appending or verifying the MAC at the end of the data.
94     *
95     * @param out space for any resulting output data.
96     * @param outOff offset into out to start copying the data at.
97     * @return number of bytes written into out.
98     * @throws IllegalStateException if the cipher is in an inappropriate state.
99     * @throws org.bouncycastle.crypto.InvalidCipherTextException if the MAC fails to match.
100     */
101    public int doFinal(byte[] out, int outOff)
102        throws IllegalStateException, InvalidCipherTextException;
103
104    /**
105     * Return the value of the MAC associated with the last stream processed.
106     *
107     * @return MAC for plaintext data.
108     */
109    public byte[] getMac();
110
111    /**
112     * return the size of the output buffer required for a processBytes
113     * an input of len bytes.
114     * <p>
115     * The returned size may be dependent on the initialisation of this cipher
116     * and may not be accurate once subsequent input data is processed - this method
117     * should be invoked immediately prior to input data being processed.
118     * </p>
119     *
120     * @param len the length of the input.
121     * @return the space required to accommodate a call to processBytes
122     * with len bytes of input.
123     */
124    public int getUpdateOutputSize(int len);
125
126    /**
127     * return the size of the output buffer required for a processBytes plus a
128     * doFinal with an input of len bytes.
129     * <p>
130     * The returned size may be dependent on the initialisation of this cipher
131     * and may not be accurate once subsequent input data is processed - this method
132     * should be invoked immediately prior to a call to final processing of input data
133     * and a call to {@link #doFinal(byte[], int)}.
134     * </p>
135     * @param len the length of the input.
136     * @return the space required to accommodate a call to processBytes and doFinal
137     * with len bytes of input.
138     */
139    public int getOutputSize(int len);
140
141    /**
142     * Reset the cipher. After resetting the cipher is in the same state
143     * as it was after the last init (if there was one).
144     */
145    public void reset();
146}
147