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Pure Java SHA-1 

This implementation is derived straight from the description written
in RFC 3174.  On Mac OS X with Java 1.8.0_91 it offers similar
throughput as MessageDigest SHA-1:

  system   239.75 MiB/s
  system   244.71 MiB/s
  system   245.00 MiB/s
  system   244.92 MiB/s

  sha1     234.08 MiB/s
  sha1     244.50 MiB/s
  sha1     242.99 MiB/s
  sha1     241.73 MiB/s

This is the fastest implementation I could come up with.  Common SHA-1
implementation tricks such as unrolling loops creates a method too
large for the JIT to effectively optimize, resulting in lower overall
hashing throughput. Using a preprocessor to perform the register
renaming of A-E also didn't help, as again the method was too large
for the JIT to effectively optimize.

Fortunately the fastest version is a naive, straight-forward
implementation very close to the description in RFC 3174.

Change-Id: I228b05c4a294ca2ad51386cf0e47978c68e1aa42
tags/v4.7.0.201704051617-r
Shawn Pearce 7 years ago
parent
9af93f43cc
commit
982f5d1bf1
4 changed files with 376 additions and 0 deletions
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  1. 1
    0
      org.eclipse.jgit.test/META-INF/MANIFEST.MF
  2. 112
    0
      org.eclipse.jgit.test/tst/org/eclipse/jgit/util/sha1/SHA1Test.java
  3. 1
    0
      org.eclipse.jgit/META-INF/MANIFEST.MF
  4. 262
    0
      org.eclipse.jgit/src/org/eclipse/jgit/util/sha1/SHA1.java

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org.eclipse.jgit.test/META-INF/MANIFEST.MF View File

@@ -49,6 +49,7 @@ Import-Package: com.googlecode.javaewah;version="[1.1.6,2.0.0)",
org.eclipse.jgit.treewalk.filter;version="[4.7.0,4.8.0)",
org.eclipse.jgit.util;version="[4.7.0,4.8.0)",
org.eclipse.jgit.util.io;version="[4.7.0,4.8.0)",
org.eclipse.jgit.util.sha1;version="[4.7.0,4.8.0)",
org.junit;version="[4.4.0,5.0.0)",
org.junit.experimental.theories;version="[4.4.0,5.0.0)",
org.junit.rules;version="[4.11.0,5.0.0)",

+ 112
- 0
org.eclipse.jgit.test/tst/org/eclipse/jgit/util/sha1/SHA1Test.java View File

@@ -0,0 +1,112 @@
/*
* Copyright (C) 2017, Google Inc.
* and other copyright owners as documented in the project's IP log.
*
* This program and the accompanying materials are made available
* under the terms of the Eclipse Distribution License v1.0 which
* accompanies this distribution, is reproduced below, and is
* available at http://www.eclipse.org/org/documents/edl-v10.php
*
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or
* without modification, are permitted provided that the following
* conditions are met:
*
* - Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* - Redistributions in binary form must reproduce the above
* copyright notice, this list of conditions and the following
* disclaimer in the documentation and/or other materials provided
* with the distribution.
*
* - Neither the name of the Eclipse Foundation, Inc. nor the
* names of its contributors may be used to endorse or promote
* products derived from this software without specific prior
* written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
* CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
* INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
* CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
* STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
* ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/

package org.eclipse.jgit.util.sha1;

import static org.junit.Assert.assertEquals;

import java.nio.charset.StandardCharsets;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;

import org.eclipse.jgit.lib.ObjectId;
import org.junit.Test;

public class SHA1Test {
private static final String TEST1 = "abc";

private static final String TEST2a = "abcdbcdecdefdefgefghfghighijhi";
private static final String TEST2b = "jkijkljklmklmnlmnomnopnopq";
private static final String TEST2 = TEST2a + TEST2b;

@Test
public void test0() throws NoSuchAlgorithmException {
ObjectId exp = ObjectId
.fromString("da39a3ee5e6b4b0d3255bfef95601890afd80709");

MessageDigest m = MessageDigest.getInstance("SHA-1");
m.update(new byte[] {});
ObjectId m1 = ObjectId.fromRaw(m.digest());

SHA1 s = SHA1.newInstance();
s.update(new byte[] {});
ObjectId s1 = ObjectId.fromRaw(s.digest());

assertEquals(m1, s1);
assertEquals(exp, s1);
}

@Test
public void test1() throws NoSuchAlgorithmException {
ObjectId exp = ObjectId
.fromString("a9993e364706816aba3e25717850c26c9cd0d89d");

MessageDigest m = MessageDigest.getInstance("SHA-1");
m.update(TEST1.getBytes(StandardCharsets.UTF_8));
ObjectId m1 = ObjectId.fromRaw(m.digest());

SHA1 s = SHA1.newInstance();
s.update(TEST1.getBytes(StandardCharsets.UTF_8));
ObjectId s1 = ObjectId.fromRaw(s.digest());

assertEquals(m1, s1);
assertEquals(exp, s1);
}

@Test
public void test2() throws NoSuchAlgorithmException {
ObjectId exp = ObjectId
.fromString("84983e441c3bd26ebaae4aa1f95129e5e54670f1");

MessageDigest m = MessageDigest.getInstance("SHA-1");
m.update(TEST2.getBytes(StandardCharsets.UTF_8));
ObjectId m1 = ObjectId.fromRaw(m.digest());

SHA1 s = SHA1.newInstance();
s.update(TEST2.getBytes(StandardCharsets.UTF_8));
ObjectId s1 = ObjectId.fromRaw(s.digest());

assertEquals(m1, s1);
assertEquals(exp, s1);
}
}

+ 1
- 0
org.eclipse.jgit/META-INF/MANIFEST.MF View File

@@ -138,6 +138,7 @@ Export-Package: org.eclipse.jgit.annotations;version="4.7.0",
org.eclipse.jgit.storage.file,
org.ietf.jgss",
org.eclipse.jgit.util.io;version="4.7.0",
org.eclipse.jgit.util.sha1;version="4.7.0",
org.eclipse.jgit.util.time;version="4.7.0"
Bundle-RequiredExecutionEnvironment: JavaSE-1.8
Import-Package: com.googlecode.javaewah;version="[1.1.6,2.0.0)",

+ 262
- 0
org.eclipse.jgit/src/org/eclipse/jgit/util/sha1/SHA1.java View File

@@ -0,0 +1,262 @@
/*
* Copyright (C) 2017, Google Inc.
* and other copyright owners as documented in the project's IP log.
*
* This program and the accompanying materials are made available
* under the terms of the Eclipse Distribution License v1.0 which
* accompanies this distribution, is reproduced below, and is
* available at http://www.eclipse.org/org/documents/edl-v10.php
*
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or
* without modification, are permitted provided that the following
* conditions are met:
*
* - Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* - Redistributions in binary form must reproduce the above
* copyright notice, this list of conditions and the following
* disclaimer in the documentation and/or other materials provided
* with the distribution.
*
* - Neither the name of the Eclipse Foundation, Inc. nor the
* names of its contributors may be used to endorse or promote
* products derived from this software without specific prior
* written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
* CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
* INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
* CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
* STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
* ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/

package org.eclipse.jgit.util.sha1;

import java.util.Arrays;

import org.eclipse.jgit.util.NB;

/**
* Pure Java implementation of SHA-1 from FIPS 180-1 / RFC 3174.
*
* <p>
* See <a href="https://tools.ietf.org/html/rfc3174">RFC 3174</a>.
*
* @since 4.7
*/
public class SHA1 {
/** @return a new context to compute a SHA-1 hash of data. */
public static SHA1 newInstance() {
return new SHA1();
}

// Magic initialization constants defined by FIPS180.
private int h0 = 0x67452301;
private int h1 = 0xEFCDAB89;
private int h2 = 0x98BADCFE;
private int h3 = 0x10325476;
private int h4 = 0xC3D2E1F0;
private final int[] w = new int[80];

/** Buffer to accumulate partial blocks to 64 byte alignment. */
private final byte[] buffer = new byte[64];

/** Total number of bytes in the message. */
private long length;

private SHA1() {
}

/**
* Update the digest computation by adding a byte.
*
* @param b
*/
public void update(byte b) {
int bufferLen = (int) (length & 63);
length++;
buffer[bufferLen] = b;
if (bufferLen == 63) {
compress(buffer, 0);
}
}

/**
* Update the digest computation by adding bytes to the message.
*
* @param in
* input array of bytes.
*/
public void update(byte[] in) {
update(in, 0, in.length);
}

/**
* Update the digest computation by adding bytes to the message.
*
* @param in
* input array of bytes.
* @param p
* offset to start at from {@code in}.
* @param len
* number of bytes to hash.
*/
public void update(byte[] in, int p, int len) {
// SHA-1 compress can only process whole 64 byte blocks.
// Hold partial updates in buffer, whose length is the low bits.
int bufferLen = (int) (length & 63);
length += len;

if (bufferLen > 0) {
int n = Math.min(64 - bufferLen, len);
System.arraycopy(in, p, buffer, bufferLen, n);
p += n;
len -= n;
if (bufferLen + n < 64) {
return;
}
compress(buffer, 0);
}
while (len >= 64) {
compress(in, p);
p += 64;
len -= 64;
}
if (len > 0) {
System.arraycopy(in, p, buffer, 0, len);
}
}

private void compress(byte[] block, int p) {
// Method 1 from RFC 3174 section 6.1.
// Method 2 (circular queue of 16 words) is slower.
int a = h0, b = h1, c = h2, d = h3, e = h4;

// Round 1: 0 <= t <= 15 comes from the input block.
for (int t = 0; t < 16; t++) {
int temp = NB.decodeInt32(block, p + (t << 2));
w[t] = temp;
temp += ((a << 5) | (a >>> 27)) // S^5(A)
+ (((c ^ d) & b) ^ d) // f: 0 <= t <= 19
+ e + 0x5A827999;
e = d;
d = c;
c = (b << 30) | (b >>> 2); // S^30(B)
b = a;
a = temp;
}

// RFC 3174 6.1.b, extend state vector to 80 words.
for (int t = 16; t < 80; t++) {
int x = w[t - 3] ^ w[t - 8] ^ w[t - 14] ^ w[t - 16];
w[t] = (x << 1) | (x >>> 31); // S^1(...)
}

// Round 1: tail
for (int t = 16; t < 20; t++) {
int temp = ((a << 5) | (a >>> 27)) // S^5(A)
+ (((c ^ d) & b) ^ d) // f: 0 <= t <= 19
+ e + w[t] + 0x5A827999;
e = d;
d = c;
c = (b << 30) | (b >>> 2); // S^30(B)
b = a;
a = temp;
}

// Round 2
for (int t = 20; t < 40; t++) {
int temp = ((a << 5) | (a >>> 27)) // S^5(A)
+ (b ^ c ^ d) // f: 20 <= t <= 39
+ e + w[t] + 0x6ED9EBA1;
e = d;
d = c;
c = (b << 30) | (b >>> 2); // S^30(B)
b = a;
a = temp;
}

// Round 3
for (int t = 40; t < 60; t++) {
int temp = ((a << 5) | (a >>> 27)) // S^5(A)
+ ((b & c) | (d & (b | c))) // f: 40 <= t <= 59
+ e + w[t] + 0x8F1BBCDC;
e = d;
d = c;
c = (b << 30) | (b >>> 2); // S^30(B)
b = a;
a = temp;
}

// Round 4
for (int t = 60; t < 80; t++) {
int temp = ((a << 5) | (a >>> 27)) // S^5(A)
+ (b ^ c ^ d) // f: 60 <= t <= 79
+ e + w[t] + 0xCA62C1D6;
e = d;
d = c;
c = (b << 30) | (b >>> 2); // S^30(B)
b = a;
a = temp;
}

h0 += a;
h1 += b;
h2 += c;
h3 += d;
h4 += e;
}

private void finish() {
int bufferLen = (int) (length & 63);
if (bufferLen > 55) {
// Last block is too small; pad, compress, pad another block.
buffer[bufferLen++] = (byte) 0x80;
Arrays.fill(buffer, bufferLen, 64, (byte) 0);
compress(buffer, 0);
Arrays.fill(buffer, 0, 56, (byte) 0);
} else {
// Last block can hold padding and length.
buffer[bufferLen++] = (byte) 0x80;
Arrays.fill(buffer, bufferLen, 56, (byte) 0);
}

// SHA-1 appends the length of the message in bits after the
// padding block (above). Here length is in bytes. Multiply by
// 8 by shifting by 3 as part of storing the 64 bit byte length
// into the two words expected in the trailer.
NB.encodeInt32(buffer, 56, (int) (length >>> (32 - 3)));
NB.encodeInt32(buffer, 60, (int) (length << 3));
compress(buffer, 0);
}

/**
* Finish the digest and return the resulting hash.
* <p>
* Once {@code digest()} is called, this instance should be discarded.
*
* @return the bytes for the resulting hash.
*/
public byte[] digest() {
finish();

byte[] b = new byte[20];
NB.encodeInt32(b, 0, h0);
NB.encodeInt32(b, 4, h1);
NB.encodeInt32(b, 8, h2);
NB.encodeInt32(b, 12, h3);
NB.encodeInt32(b, 16, h4);
return b;
}
}

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