package net.i2p.imagegen;
/*
*
* Translated to Java and modified from:
*
* gnutls lib/extras/randomart.c
*
*/
/* $OpenBSD: key.c,v 1.98 2011/10/18 04:58:26 djm Exp $ */
/*
* Copyright (c) 2000, 2001 Markus Friedl. All rights reserved.
* Copyright (c) 2008 Alexander von Gernler. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. 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.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 AUTHOR 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.
*/
import net.i2p.data.DataHelper;
/**
* Draw an ASCII-Art representing the fingerprint so human brain can
* profit from its built-in pattern recognition ability.
* This technique is called "random art" and can be found in some
* scientific publications like this original paper:
*
* "Hash Visualization: a New Technique to improve Real-World Security",
* Perrig A. and Song D., 1999, International Workshop on Cryptographic
* Techniques and E-Commerce (CrypTEC '99)
* sparrow.ece.cmu.edu/~adrian/projects/validation/validation.pdf
*
* The subject came up in a talk by Dan Kaminsky, too.
*
* If you see the picture is different, the key is different.
* If the picture looks the same, you still know nothing.
*
* The algorithm used here is a worm crawling over a discrete plane,
* leaving a trace (augmenting the field) everywhere it goes.
* Movement is taken from dgst_raw 2bit-wise. Bumping into walls
* makes the respective movement vector be ignored for this turn.
* Graphs are not unambiguous, because circles in graphs can be
* walked in either direction.
*
* @since 0.9.25
*/
public class RandomArt {
/*
* Field sizes for the random art. Have to be odd, so the starting point
* can be in the exact middle of the picture, and FLDBASE should be >=8 .
* Else pictures would be too dense, and drawing the frame would
* fail, too, because the key type would not fit in anymore.
*/
private static final int FLDBASE = 8;
private static final int FLDSIZE_Y = FLDBASE + 1;
private static final int FLDSIZE_X = FLDBASE * 2 + 1;
/*
* Chars to be used after each other every time the worm
* intersects with itself. Matter of taste.
*/
private static final String A_augmentation_string = " .o+=*BOX@%&#/^SE";
// https://en.wikipedia.org/wiki/Miscellaneous_Symbols
private static final String U_augmentation_string = " \u2600\u2601\u2602\u2603" +
"\u2604\u2605\u2606\u2607" +
"\u2608\u2609\u260a\u260b" +
"\u260c\u260d\u260e\u260f";
private static final char A_BOX_TOP = '-';
private static final char A_BOX_BOTTOM = '-';
private static final char A_BOX_LEFT = '|';
private static final char A_BOX_RIGHT = '|';
private static final char A_BOX_TL = '+';
private static final char A_BOX_TR = '+';
private static final char A_BOX_BL = '+';
private static final char A_BOX_BR = '+';
// https://en.wikipedia.org/wiki/Box-drawing_characters
// these are the thin singles
private static final char U_BOX_TOP = '\u2500';
private static final char U_BOX_BOTTOM = '\u2500';
private static final char U_BOX_LEFT = '\u2502';
private static final char U_BOX_RIGHT = '\u2502';
private static final char U_BOX_TL = '\u250c';
private static final char U_BOX_TR = '\u2510';
private static final char U_BOX_BL = '\u2514';
private static final char U_BOX_BR = '\u2518';
private static final int BASE = 0x778899;
/**
* @param dgst_raw the data to be visualized, recommend 64 bytes or less
* @param key_type output in the first line, recommend 6 chars or less
* @param key_size output in the first line
* @param prefix if non-null, prepend to every line
*/
public static String gnutls_key_fingerprint_randomart(final byte[] dgst_raw,
final String key_type,
final int key_size,
final String prefix,
final boolean unicode,
final boolean html)
{
final String augmentation_string = unicode ? U_augmentation_string : A_augmentation_string;
final char BOX_TOP = unicode ? U_BOX_TOP : A_BOX_TOP;
final char BOX_BOTTOM = unicode ? U_BOX_BOTTOM : A_BOX_BOTTOM;
final char BOX_LEFT = unicode ? U_BOX_LEFT : A_BOX_LEFT;
final char BOX_RIGHT = unicode ? U_BOX_RIGHT : A_BOX_RIGHT;
final char BOX_TL = unicode ? U_BOX_TL : A_BOX_TL;
final char BOX_TR = unicode ? U_BOX_TR : A_BOX_TR;
final char BOX_BL = unicode ? U_BOX_BL : A_BOX_BL;
final char BOX_BR = unicode ? U_BOX_BR : A_BOX_BR;
final String NL = System.getProperty("line.separator");
final int dgst_raw_len = dgst_raw.length;
final byte[][] field = new byte[FLDSIZE_X][FLDSIZE_Y];
final byte[][] color = new byte[FLDSIZE_X][FLDSIZE_Y];
final int len = augmentation_string.length() - 1;
int prefix_len = 0;
if (prefix != null)
prefix_len = prefix.length();
int x = FLDSIZE_X / 2;
int y = FLDSIZE_Y / 2;
/* process raw key */
for (int i = 0; i < dgst_raw_len; i++) {
int input;
/* each byte conveys four 2-bit move commands */
input = dgst_raw[i];
for (int b = 0; b < 4; b++) {
/* evaluate 2 bit, rest is shifted later */
x += ((input & 0x1) != 0) ? 1 : -1;
y += ((input & 0x2) != 0) ? 1 : -1;
/* assure we are still in bounds */
x = Math.max(x, 0);
y = Math.max(y, 0);
x = Math.min(x, FLDSIZE_X - 1);
y = Math.min(y, FLDSIZE_Y - 1);
/* augment the field */
if ((field[x][y] & 0xff) < len - 2)
field[x][y]++;
color[x][y] = (byte) i;
input = input >> 2;
}
}
/* mark starting point and end point */
field[FLDSIZE_X / 2][FLDSIZE_Y / 2] = (byte) (len - 1);
field[x][y] = (byte) len;
final String size_txt;
if (key_size > 0)
size_txt = String.format(" %4d", key_size);
else
size_txt = "";
/* fill in retval */
StringBuilder retval = new StringBuilder(1024);
long base = 0;
if (html) {
// Pick a color base. We use the first 3 bytes of the data,
// but normalize by 75% since we're designed for a white background.
int clen = Math.min(3, dgst_raw_len);
byte[] cbase = new byte[clen];
for (int i = 0; i < clen; i++) {
cbase[i] = (byte) ((dgst_raw[i] & 0xff) * 5 / 8);
}
base = DataHelper.fromLong(cbase, 0, clen);
retval.append("<font color=\"#")
.append(getColor(base, 0))
.append("\"><pre>\n");
}
if (prefix_len > 0)
retval.append(String.format("%s" + BOX_TL + BOX_TOP + BOX_TOP + "[%4s%s]",
prefix, key_type, size_txt));
else
retval.append(String.format("" + BOX_TL + BOX_TOP + BOX_TOP + "[%4s%s]", key_type,
size_txt));
/* output upper border */
for (int i = 0; i < FLDSIZE_X - Math.max(key_type.length(), 4) - 9; i++)
retval.append(BOX_TOP);
retval.append(BOX_TR);
retval.append(NL);
if (prefix_len > 0) {
retval.append(prefix);
}
/* output content */
for (y = 0; y < FLDSIZE_Y; y++) {
retval.append(BOX_LEFT);
for (x = 0; x < FLDSIZE_X; x++) {
int idx = Math.min(field[x][y], len);
if (html && idx != 0)
retval.append("<span style=\"color: #")
.append(getColor(base, color[x][y] & 0xff))
.append("\">");
retval.append(augmentation_string.charAt(idx));
if (html && idx != 0)
retval.append("</span>");
}
retval.append(BOX_RIGHT);
retval.append(NL);
if (prefix_len > 0) {
retval.append(prefix);
}
}
/* output lower border */
retval.append(BOX_BL);
for (int i = 0; i < FLDSIZE_X; i++)
retval.append(BOX_BOTTOM);
retval.append(BOX_BR);
retval.append(NL);
if (html)
retval.append("</pre></font>\n");
return retval.toString();
}
private static String getColor(long base, int mod) {
if (mod != 0) {
//base += mod * 16;
//base += mod * 16 * 256;
base += mod * 5 * 256 * 256;
}
if (base > 0xffffff || base < 0)
base &= 0xffffff;
return String.format("%06x", base);
}
public static void main(String[] args) {
try {
boolean uni = true;
boolean html = true;
if (html)
System.out.println("<html><head><meta http-equiv=\"Content-Type\" content=\"text/html; charset=UTF-8\"></head><body>");
byte[] b = new byte[16];
net.i2p.util.RandomSource.getInstance().nextBytes(b);
String art = gnutls_key_fingerprint_randomart(b, "SHA", 128, null, uni, html);
System.out.println(art);
System.out.println("");
b = new byte[32];
for (int i = 0; i < 5; i++) {
net.i2p.util.RandomSource.getInstance().nextBytes(b);
art = gnutls_key_fingerprint_randomart(b, "XSHA", 256, null, uni, html);
System.out.println(art);
System.out.println("");
}
b = new byte[48];
net.i2p.util.RandomSource.getInstance().nextBytes(b);
art = gnutls_key_fingerprint_randomart(b, "XXSHA", 384, null, uni, html);
System.out.println(art);
System.out.println("");
b = new byte[64];
net.i2p.util.RandomSource.getInstance().nextBytes(b);
art = gnutls_key_fingerprint_randomart(b, "XXXSHA", 512, null, uni, html);
System.out.println(art);
if (html)
System.out.println("</body></html>");
} catch (RuntimeException e) {
e.printStackTrace();
}
}
}