001/*
002 * Licensed to the Apache Software Foundation (ASF) under one or more
003 * contributor license agreements.  See the NOTICE file distributed with
004 * this work for additional information regarding copyright ownership.
005 * The ASF licenses this file to You under the Apache License, Version 2.0
006 * (the "License"); you may not use this file except in compliance with
007 * the License.  You may obtain a copy of the License at
008 *
009 *      http://www.apache.org/licenses/LICENSE-2.0
010 *
011 * Unless required by applicable law or agreed to in writing, software
012 * distributed under the License is distributed on an "AS IS" BASIS,
013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014 * See the License for the specific language governing permissions and
015 * limitations under the License.
016 */
017package org.apache.commons.codec.digest;
018
019import java.util.Arrays;
020import java.util.Objects;
021
022/**
023 * Implements the Blake3 algorithm providing a {@linkplain #initHash() hash function} with extensible output (XOF), a
024 * {@linkplain #initKeyedHash(byte[]) keyed hash function} (MAC, PRF), and a
025 * {@linkplain #initKeyDerivationFunction(byte[]) key derivation function} (KDF). Blake3 has a 128-bit security level
026 * and a default output length of 256 bits (32 bytes) which can extended up to 2<sup>64</sup> bytes.
027 * <h2>Hashing</h2>
028 * <p>Hash mode calculates the same output hash given the same input bytes and can be used as both a message digest and
029 * and extensible output function.</p>
030 * <pre>{@code
031 *      Blake3 hasher = Blake3.initHash();
032 *      hasher.update("Hello, world!".getBytes(StandardCharsets.UTF_8));
033 *      byte[] hash = new byte[32];
034 *      hasher.doFinalize(hash);
035 * }</pre>
036 * <h2>Keyed Hashing</h2>
037 * <p>Keyed hashes take a 32-byte secret key and calculates a message authentication code on some input bytes. These
038 * also work as pseudo-random functions (PRFs) with extensible output similar to the extensible hash output. Note that
039 * Blake3 keyed hashes have the same performance as plain hashes; the key is used in initialization in place of a
040 * standard initialization vector used for plain hashing.</p>
041 * <pre>{@code
042 *      SecureRandom random = SecureRandom.getInstanceStrong();
043 *      byte[] key = new byte[32];
044 *      random.nextBytes(key);
045 *      Blake3 hasher = Blake3.initKeyedHash(key);
046 *      hasher.update("Hello, Alice!".getBytes(StandardCharsets.UTF_8));
047 *      byte[] mac = new byte[32];
048 *      hasher.doFinalize(mac);
049 * }</pre>
050 * <h2>Key Derivation</h2>
051 * <p>A specific hash mode for deriving session keys and other derived keys in a unique key derivation context
052 * identified by some sequence of bytes. These context strings should be unique but do not need to be kept secret.
053 * Additional input data is hashed for key material which can be finalized to derive subkeys.</p>
054 * <pre>{@code
055 *      String context = "org.apache.commons.codec.digest.Blake3Example";
056 *      byte[] sharedSecret = ...;
057 *      byte[] senderId = ...;
058 *      byte[] recipientId = ...;
059 *      Blake3 kdf = Blake3.initKeyDerivationFunction(context.getBytes(StandardCharsets.UTF_8));
060 *      kdf.update(sharedSecret);
061 *      kdf.update(senderId);
062 *      kdf.update(recipientId);
063 *      byte[] txKey = new byte[32];
064 *      byte[] rxKey = new byte[32];
065 *      kdf.doFinalize(txKey);
066 *      kdf.doFinalize(rxKey);
067 * }</pre>
068 * <p>
069 * Adapted from the ISC-licensed O(1) Cryptography library by Matt Sicker and ported from the reference public domain
070 * implementation by Jack O'Connor.
071 * </p>
072 *
073 * @see <a href="https://github.com/BLAKE3-team/BLAKE3">BLAKE3 hash function</a>
074 * @since 1.16
075 */
076public final class Blake3 {
077
078    private static final class ChunkState {
079
080        private int[] chainingValue;
081        private final long chunkCounter;
082        private final int flags;
083
084        private final byte[] block = new byte[BLOCK_LEN];
085        private int blockLength;
086        private int blocksCompressed;
087
088        private ChunkState(final int[] key, final long chunkCounter, final int flags) {
089            chainingValue = key;
090            this.chunkCounter = chunkCounter;
091            this.flags = flags;
092        }
093
094        private int length() {
095            return BLOCK_LEN * blocksCompressed + blockLength;
096        }
097
098        private Output output() {
099            final int[] blockWords = unpackInts(block, BLOCK_INTS);
100            final int outputFlags = flags | startFlag() | CHUNK_END;
101            return new Output(chainingValue, blockWords, chunkCounter, blockLength, outputFlags);
102        }
103
104        private int startFlag() {
105            return blocksCompressed == 0 ? CHUNK_START : 0;
106        }
107
108        private void update(final byte[] input, int offset, int length) {
109            while (length > 0) {
110                if (blockLength == BLOCK_LEN) {
111                    // If the block buffer is full, compress it and clear it. More
112                    // input is coming, so this compression is not CHUNK_END.
113                    final int[] blockWords = unpackInts(block, BLOCK_INTS);
114                    chainingValue = Arrays.copyOf(
115                            compress(chainingValue, blockWords, BLOCK_LEN, chunkCounter, flags | startFlag()),
116                            CHAINING_VALUE_INTS);
117                    blocksCompressed++;
118                    blockLength = 0;
119                    Arrays.fill(block, (byte) 0);
120                }
121
122                final int want = BLOCK_LEN - blockLength;
123                final int take = Math.min(want, length);
124                System.arraycopy(input, offset, block, blockLength, take);
125                blockLength += take;
126                offset += take;
127                length -= take;
128            }
129        }
130    }
131    private static final class EngineState {
132        private final int[] key;
133        private final int flags;
134        // Space for 54 subtree chaining values: 2^54 * CHUNK_LEN = 2^64
135        // No more than 54 entries can ever be added to this stack (after updating 2^64 bytes and not finalizing any)
136        // so we preallocate the stack here. This can be smaller in environments where the data limit is expected to
137        // be much lower.
138        private final int[][] cvStack = new int[54][];
139        private int stackLen;
140        private ChunkState state;
141
142        private EngineState(final int[] key, final int flags) {
143            this.key = key;
144            this.flags = flags;
145            state = new ChunkState(key, 0, flags);
146        }
147
148        // Section 5.1.2 of the BLAKE3 spec explains this algorithm in more detail.
149        private void addChunkCV(final int[] firstCV, final long totalChunks) {
150            // This chunk might complete some subtrees. For each completed subtree,
151            // its left child will be the current top entry in the CV stack, and
152            // its right child will be the current value of `newCV`. Pop each left
153            // child off the stack, merge it with `newCV`, and overwrite `newCV`
154            // with the result. After all these merges, push the final value of
155            // `newCV` onto the stack. The number of completed subtrees is given
156            // by the number of trailing 0-bits in the new total number of chunks.
157            int[] newCV = firstCV;
158            long chunkCounter = totalChunks;
159            while ((chunkCounter & 1) == 0) {
160                newCV = parentChainingValue(popCV(), newCV, key, flags);
161                chunkCounter >>= 1;
162            }
163            pushCV(newCV);
164        }
165
166        private void inputData(final byte[] in, int offset, int length) {
167            while (length > 0) {
168                // If the current chunk is complete, finalize it and reset the
169                // chunk state. More input is coming, so this chunk is not ROOT.
170                if (state.length() == CHUNK_LEN) {
171                    final int[] chunkCV = state.output().chainingValue();
172                    final long totalChunks = state.chunkCounter + 1;
173                    addChunkCV(chunkCV, totalChunks);
174                    state = new ChunkState(key, totalChunks, flags);
175                }
176
177                // Compress input bytes into the current chunk state.
178                final int want = CHUNK_LEN - state.length();
179                final int take = Math.min(want, length);
180                state.update(in, offset, take);
181                offset += take;
182                length -= take;
183            }
184        }
185
186        private void outputHash(final byte[] out, final int offset, final int length) {
187            // Starting with the Output from the current chunk, compute all the
188            // parent chaining values along the right edge of the tree, until we
189            // have the root Output.
190            Output output = state.output();
191            int parentNodesRemaining = stackLen;
192            while (parentNodesRemaining-- > 0) {
193                final int[] parentCV = cvStack[parentNodesRemaining];
194                output = parentOutput(parentCV, output.chainingValue(), key, flags);
195            }
196            output.rootOutputBytes(out, offset, length);
197        }
198
199        private int[] popCV() {
200            return cvStack[--stackLen];
201        }
202
203        private void pushCV(final int[] cv) {
204            cvStack[stackLen++] = cv;
205        }
206
207        private void reset() {
208            stackLen = 0;
209            Arrays.fill(cvStack, null);
210            state = new ChunkState(key, 0, flags);
211        }
212    }
213
214    /**
215     * Represents the state just prior to either producing an eight word chaining value or any number of output bytes
216     * when the ROOT flag is set.
217     */
218    private static final class Output {
219
220        private final int[] inputChainingValue;
221        private final int[] blockWords;
222        private final long counter;
223        private final int blockLength;
224        private final int flags;
225
226        private Output(final int[] inputChainingValue, final int[] blockWords, final long counter, final int blockLength, final int flags) {
227            this.inputChainingValue = inputChainingValue;
228            this.blockWords = blockWords;
229            this.counter = counter;
230            this.blockLength = blockLength;
231            this.flags = flags;
232        }
233
234        private int[] chainingValue() {
235            return Arrays.copyOf(compress(inputChainingValue, blockWords, blockLength, counter, flags), CHAINING_VALUE_INTS);
236        }
237
238        private void rootOutputBytes(final byte[] out, int offset, int length) {
239            int outputBlockCounter = 0;
240            while (length > 0) {
241                int chunkLength = Math.min(OUT_LEN * 2, length);
242                length -= chunkLength;
243                final int[] words = compress(inputChainingValue, blockWords, blockLength, outputBlockCounter++, flags | ROOT);
244                int wordCounter = 0;
245                while (chunkLength > 0) {
246                    final int wordLength = Math.min(Integer.BYTES, chunkLength);
247                    packInt(words[wordCounter++], out, offset, wordLength);
248                    offset += wordLength;
249                    chunkLength -= wordLength;
250                }
251            }
252        }
253    }
254
255    private static final int BLOCK_LEN = 64;
256    private static final int BLOCK_INTS = BLOCK_LEN / Integer.BYTES;
257    private static final int KEY_LEN = 32;
258    private static final int KEY_INTS = KEY_LEN / Integer.BYTES;
259    private static final int OUT_LEN = 32;
260    private static final int CHUNK_LEN = 1024;
261    private static final int CHAINING_VALUE_INTS = 8;
262
263    /**
264     * Standard hash key used for plain hashes; same initialization vector as Blake2s.
265     */
266    private static final int[] IV = { 0x6A09E667, 0xBB67AE85, 0x3C6EF372, 0xA54FF53A, 0x510E527F, 0x9B05688C, 0x1F83D9AB, 0x5BE0CD19 };
267
268    // domain flags
269    private static final int CHUNK_START = 1;
270    private static final int CHUNK_END = 1 << 1;
271    private static final int PARENT = 1 << 2;
272    private static final int ROOT = 1 << 3;
273    private static final int KEYED_HASH = 1 << 4;
274    private static final int DERIVE_KEY_CONTEXT = 1 << 5;
275    private static final int DERIVE_KEY_MATERIAL = 1 << 6;
276
277    /**
278     * Pre-permuted for all 7 rounds; the second row (2,6,3,...) indicates the base permutation.
279     */
280    // @formatter:off
281    private static final byte[][] MSG_SCHEDULE = {
282            { 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15 },
283            { 2, 6, 3, 10, 7, 0, 4, 13, 1, 11, 12, 5, 9, 14, 15, 8 },
284            { 3, 4, 10, 12, 13, 2, 7, 14, 6, 5, 9, 0, 11, 15, 8, 1 },
285            { 10, 7, 12, 9, 14, 3, 13, 15, 4, 0, 11, 2, 5, 8, 1, 6 },
286            { 12, 13, 9, 11, 15, 10, 14, 8, 7, 2, 5, 3, 0, 1, 6, 4 },
287            { 9, 14, 11, 5, 8, 12, 15, 1, 13, 3, 0, 10, 2, 6, 4, 7 },
288            { 11, 15, 5, 0, 1, 9, 8, 6, 14, 10, 2, 12, 3, 4, 7, 13 }
289    };
290    // @formatter:on
291
292    private static void checkBufferArgs(final byte[] buffer, final int offset, final int length) {
293        Objects.requireNonNull(buffer);
294        if (offset < 0) {
295            throw new IndexOutOfBoundsException("Offset must be non-negative");
296        }
297        if (length < 0) {
298            throw new IndexOutOfBoundsException("Length must be non-negative");
299        }
300        final int bufferLength = buffer.length;
301        if (offset > bufferLength - length) {
302            throw new IndexOutOfBoundsException("Offset " + offset + " and length " + length + " out of bounds with buffer length " + bufferLength);
303        }
304    }
305
306    private static int[] compress(final int[] chainingValue, final int[] blockWords, final int blockLength, final long counter, final int flags) {
307        final int[] state = Arrays.copyOf(chainingValue, BLOCK_INTS);
308        System.arraycopy(IV, 0, state, 8, 4);
309        state[12] = (int) counter;
310        state[13] = (int) (counter >> Integer.SIZE);
311        state[14] = blockLength;
312        state[15] = flags;
313        for (int i = 0; i < 7; i++) {
314            final byte[] schedule = MSG_SCHEDULE[i];
315            round(state, blockWords, schedule);
316        }
317        for (int i = 0; i < state.length / 2; i++) {
318            state[i] ^= state[i + 8];
319            state[i + 8] ^= chainingValue[i];
320        }
321        return state;
322    }
323
324    /**
325     * The mixing function, G, which mixes either a column or a diagonal.
326     */
327    private static void g(final int[] state, final int a, final int b, final int c, final int d, final int mx, final int my) {
328        state[a] += state[b] + mx;
329        state[d] = Integer.rotateRight(state[d] ^ state[a], 16);
330        state[c] += state[d];
331        state[b] = Integer.rotateRight(state[b] ^ state[c], 12);
332        state[a] += state[b] + my;
333        state[d] = Integer.rotateRight(state[d] ^ state[a], 8);
334        state[c] += state[d];
335        state[b] = Integer.rotateRight(state[b] ^ state[c], 7);
336    }
337
338    /**
339     * Calculates the Blake3 hash of the provided data.
340     *
341     * @param data source array to absorb data from
342     * @return 32-byte hash squeezed from the provided data
343     * @throws NullPointerException if data is null
344     */
345    public static byte[] hash(final byte[] data) {
346        return Blake3.initHash().update(data).doFinalize(OUT_LEN);
347    }
348
349    /**
350     * Constructs a fresh Blake3 hash function. The instance returned functions as an arbitrary length message digest.
351     *
352     * @return fresh Blake3 instance in hashed mode
353     */
354    public static Blake3 initHash() {
355        return new Blake3(IV, 0);
356    }
357
358    /**
359     * Constructs a fresh Blake3 key derivation function using the provided key derivation context byte string.
360     * The instance returned functions as a key-derivation function which can further absorb additional context data
361     * before squeezing derived key data.
362     *
363     * @param kdfContext a globally unique key-derivation context byte string to separate key derivation contexts from each other
364     * @return fresh Blake3 instance in key derivation mode
365     * @throws NullPointerException if kdfContext is null
366     */
367    public static Blake3 initKeyDerivationFunction(final byte[] kdfContext) {
368        Objects.requireNonNull(kdfContext);
369        final EngineState kdf = new EngineState(IV, DERIVE_KEY_CONTEXT);
370        kdf.inputData(kdfContext, 0, kdfContext.length);
371        final byte[] key = new byte[KEY_LEN];
372        kdf.outputHash(key, 0, key.length);
373        return new Blake3(unpackInts(key, KEY_INTS), DERIVE_KEY_MATERIAL);
374    }
375
376    /**
377     * Constructs a fresh Blake3 keyed hash function. The instance returned functions as a pseudorandom function (PRF) or as a
378     * message authentication code (MAC).
379     *
380     * @param key 32-byte secret key
381     * @return fresh Blake3 instance in keyed mode using the provided key
382     * @throws NullPointerException     if key is null
383     * @throws IllegalArgumentException if key is not 32 bytes
384     */
385    public static Blake3 initKeyedHash(final byte[] key) {
386        Objects.requireNonNull(key);
387        if (key.length != KEY_LEN) {
388            throw new IllegalArgumentException("Blake3 keys must be 32 bytes");
389        }
390        return new Blake3(unpackInts(key, KEY_INTS), KEYED_HASH);
391    }
392
393    /**
394     * Calculates the Blake3 keyed hash (MAC) of the provided data.
395     *
396     * @param key  32-byte secret key
397     * @param data source array to absorb data from
398     * @return 32-byte mac squeezed from the provided data
399     * @throws NullPointerException if key or data are null
400     */
401    public static byte[] keyedHash(final byte[] key, final byte[] data) {
402        return Blake3.initKeyedHash(key).update(data).doFinalize(OUT_LEN);
403    }
404
405    private static void packInt(final int value, final byte[] dst, final int off, final int len) {
406        for (int i = 0; i < len; i++) {
407            dst[off + i] = (byte) (value >>> i * Byte.SIZE);
408        }
409    }
410
411    private static int[] parentChainingValue(final int[] leftChildCV, final int[] rightChildCV, final int[] key, final int flags) {
412        return parentOutput(leftChildCV, rightChildCV, key, flags).chainingValue();
413    }
414
415    private static Output parentOutput(final int[] leftChildCV, final int[] rightChildCV, final int[] key, final int flags) {
416        final int[] blockWords = Arrays.copyOf(leftChildCV, BLOCK_INTS);
417        System.arraycopy(rightChildCV, 0, blockWords, 8, CHAINING_VALUE_INTS);
418        return new Output(key.clone(), blockWords, 0, BLOCK_LEN, flags | PARENT);
419    }
420
421    private static void round(final int[] state, final int[] msg, final byte[] schedule) {
422        // Mix the columns.
423        g(state, 0, 4, 8, 12, msg[schedule[0]], msg[schedule[1]]);
424        g(state, 1, 5, 9, 13, msg[schedule[2]], msg[schedule[3]]);
425        g(state, 2, 6, 10, 14, msg[schedule[4]], msg[schedule[5]]);
426        g(state, 3, 7, 11, 15, msg[schedule[6]], msg[schedule[7]]);
427
428        // Mix the diagonals.
429        g(state, 0, 5, 10, 15, msg[schedule[8]], msg[schedule[9]]);
430        g(state, 1, 6, 11, 12, msg[schedule[10]], msg[schedule[11]]);
431        g(state, 2, 7, 8, 13, msg[schedule[12]], msg[schedule[13]]);
432        g(state, 3, 4, 9, 14, msg[schedule[14]], msg[schedule[15]]);
433    }
434
435    private static int unpackInt(final byte[] buf, final int off) {
436        return buf[off] & 0xFF | (buf[off + 1] & 0xFF) << 8 | (buf[off + 2] & 0xFF) << 16 | (buf[off + 3] & 0xFF) << 24;
437    }
438
439    private static int[] unpackInts(final byte[] buf, final int nrInts) {
440        final int[] values = new int[nrInts];
441        for (int i = 0, off = 0; i < nrInts; i++, off += Integer.BYTES) {
442            values[i] = unpackInt(buf, off);
443        }
444        return values;
445    }
446
447    private final EngineState engineState;
448
449    private Blake3(final int[] key, final int flags) {
450        engineState = new EngineState(key, flags);
451    }
452
453    /**
454     * Finalizes hash output data that depends on the sequence of updated bytes preceding this invocation and any
455     * previously finalized bytes. Note that this can finalize up to 2<sup>64</sup> bytes per instance.
456     *
457     * @param out destination array to finalize bytes into
458     * @return {@code this} instance.
459     * @throws NullPointerException if out is null
460     */
461    public Blake3 doFinalize(final byte[] out) {
462        return doFinalize(out, 0, out.length);
463    }
464
465    /**
466     * Finalizes an arbitrary number of bytes into the provided output array that depends on the sequence of previously
467     * updated and finalized bytes. Note that this can finalize up to 2<sup>64</sup> bytes per instance.
468     *
469     * @param out    destination array to finalize bytes into
470     * @param offset where in the array to begin writing bytes to
471     * @param length number of bytes to finalize
472     * @return {@code this} instance.
473     * @throws NullPointerException      if out is null
474     * @throws IndexOutOfBoundsException if offset or length are negative or if offset + length is greater than the
475     *                                   length of the provided array
476     */
477    public Blake3 doFinalize(final byte[] out, final int offset, final int length) {
478        checkBufferArgs(out, offset, length);
479        engineState.outputHash(out, offset, length);
480        return this;
481    }
482
483    /**
484     * Squeezes and returns an arbitrary number of bytes dependent on the sequence of previously absorbed and squeezed bytes.
485     *
486     * @param nrBytes number of bytes to finalize
487     * @return requested number of finalized bytes
488     * @throws IllegalArgumentException if nrBytes is negative
489     */
490    public byte[] doFinalize(final int nrBytes) {
491        if (nrBytes < 0) {
492            throw new IllegalArgumentException("Requested bytes must be non-negative");
493        }
494        final byte[] hash = new byte[nrBytes];
495        doFinalize(hash);
496        return hash;
497    }
498
499    /**
500     * Resets this instance back to its initial state when it was first constructed.
501     * @return {@code this} instance.
502     */
503    public Blake3 reset() {
504        engineState.reset();
505        return this;
506    }
507
508    /**
509     * Updates this hash state using the provided bytes.
510     *
511     * @param in source array to update data from
512     * @return {@code this} instance.
513     * @throws NullPointerException if in is null
514     */
515    public Blake3 update(final byte[] in) {
516        return update(in, 0, in.length);
517    }
518
519    /**
520     * Updates this hash state using the provided bytes at an offset.
521     *
522     * @param in     source array to update data from
523     * @param offset where in the array to begin reading bytes
524     * @param length number of bytes to update
525     * @return {@code this} instance.
526     * @throws NullPointerException      if in is null
527     * @throws IndexOutOfBoundsException if offset or length are negative or if offset + length is greater than the
528     *                                   length of the provided array
529     */
530    public Blake3 update(final byte[] in, final int offset, final int length) {
531        checkBufferArgs(in, offset, length);
532        engineState.inputData(in, offset, length);
533        return this;
534    }
535
536}