org.apache.sshd.common.config.keys.KeyRandomArt Maven / Gradle / Ivy
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This artifact provides a single jar that contains all classes required to use remote EJB and JMS, including
all dependencies. It is intended for use by those not using maven, maven users should just import the EJB and
JMS BOM's instead (shaded JAR's cause lots of problems with maven, as it is very easy to inadvertently end up
with different versions on classes on the class path).
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/*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing,
* software distributed under the License is distributed on an
* "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
* KIND, either express or implied. See the License for the
* specific language governing permissions and limitations
* under the License.
*/
package org.apache.sshd.common.config.keys;
import java.io.IOException;
import java.io.StreamCorruptedException;
import java.security.KeyPair;
import java.security.PublicKey;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;
import java.util.Iterator;
import java.util.LinkedList;
import java.util.List;
import java.util.Objects;
import org.apache.sshd.common.AlgorithmNameProvider;
import org.apache.sshd.common.Factory;
import org.apache.sshd.common.digest.Digest;
import org.apache.sshd.common.keyprovider.KeyIdentityProvider;
import org.apache.sshd.common.keyprovider.KeySizeIndicator;
import org.apache.sshd.common.session.SessionContext;
import org.apache.sshd.common.util.GenericUtils;
import org.apache.sshd.common.util.ValidateUtils;
/**
* 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)
*
* @author Apache MINA SSHD Project
* @see Original article
* @see C implementation
*/
public class KeyRandomArt implements AlgorithmNameProvider, KeySizeIndicator {
public static final int FLDBASE = 8;
public static final int FLDSIZE_Y = FLDBASE + 1;
public static final int FLDSIZE_X = FLDBASE * 2 + 1;
public static final String AUGMENTATION_STRING = " .o+=*BOX@%&#/^SE";
private final String algorithm;
private final int keySize;
private final char[][] field = new char[FLDSIZE_X][FLDSIZE_Y];
public KeyRandomArt(PublicKey key) throws Exception {
this(key, KeyUtils.getDefaultFingerPrintFactory());
}
public KeyRandomArt(PublicKey key, Factory f) throws Exception {
this(key, Objects.requireNonNull(f, "No digest factory").create());
}
public KeyRandomArt(PublicKey key, Digest d) throws Exception {
this(Objects.requireNonNull(key, "No key provided").getAlgorithm(),
KeyUtils.getKeySize(key),
KeyUtils.getRawFingerprint(Objects.requireNonNull(d, "No key digest"), key));
}
/**
* @param algorithm The key algorithm
* @param keySize The key size in bits
* @param digest The key digest
*/
public KeyRandomArt(String algorithm, int keySize, byte[] digest) {
this.algorithm = ValidateUtils.checkNotNullAndNotEmpty(algorithm, "No algorithm provided");
ValidateUtils.checkTrue(keySize > 0, "Invalid key size: %d", keySize);
this.keySize = keySize;
Objects.requireNonNull(digest, "No key digest provided");
int x = FLDSIZE_X / 2;
int y = FLDSIZE_Y / 2;
int len = AUGMENTATION_STRING.length() - 1;
for (int i = 0; i < digest.length; i++) {
/* each byte conveys four 2-bit move commands */
int input = digest[i] & 0xFF;
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] < (len - 2)) {
field[x][y]++;
}
input = input >> 2;
}
}
/* mark starting point and end point */
field[FLDSIZE_X / 2][FLDSIZE_Y / 2] = (char) (len - 1);
field[x][y] = (char) len;
}
/**
* @return The algorithm that was used to generate the key - e.g., "RSA", "DSA", "EC".
*/
@Override
public String getAlgorithm() {
return algorithm;
}
@Override
public int getKeySize() {
return keySize;
}
/**
* Outputs the generated random art
*
* @param The {@link Appendable} output writer
* @param sb The writer
* @return The updated writer instance
* @throws IOException If failed to write the combined result
*/
public A append(A sb) throws IOException {
// Upper border
String s = String.format("+--[%4s %4d]", getAlgorithm(), getKeySize());
sb.append(s);
for (int index = s.length(); index <= FLDSIZE_X; index++) {
sb.append('-');
}
sb.append('+');
sb.append('\n');
// contents
int len = AUGMENTATION_STRING.length() - 1;
for (int y = 0; y < FLDSIZE_Y; y++) {
sb.append('|');
for (int x = 0; x < FLDSIZE_X; x++) {
char ch = field[x][y];
sb.append(AUGMENTATION_STRING.charAt(Math.min(ch, len)));
}
sb.append('|');
sb.append('\n');
}
// lower border
sb.append('+');
for (int index = 0; index < FLDSIZE_X; index++) {
sb.append('-');
}
sb.append('+');
sb.append('\n');
return sb;
}
@Override
public String toString() {
try {
return append(new StringBuilder((FLDSIZE_X + 4) * (FLDSIZE_Y + 3))).toString();
} catch (IOException e) {
return e.getClass().getSimpleName(); // unexpected
}
}
/**
* Combines the arts in a user-friendly way so they are aligned with each other
*
* @param separator The separator to use between the arts - if empty char ('\0') then no separation is done
* @param arts The {@link KeyRandomArt}s to combine - ignored if {@code null}/empty
* @return The combined result
*/
public static String combine(char separator, Collection arts) {
if (GenericUtils.isEmpty(arts)) {
return "";
}
try {
return combine(new StringBuilder(arts.size() * (FLDSIZE_X + 4) * (FLDSIZE_Y + 3)), separator, arts).toString();
} catch (IOException e) {
return e.getClass().getSimpleName(); // unexpected
}
}
/**
* Creates the combined representation of the random art entries for the provided keys
*
* @param session The {@link SessionContext} for invoking this load command - may be {@code null} if not invoked
* within a session context (e.g., offline tool or session unknown).
* @param separator The separator to use between the arts - if empty char ('\0') then no separation is done
* @param provider The {@link KeyIdentityProvider} - ignored if {@code null} or has no keys to provide
* @return The combined representation
* @throws Exception If failed to extract or combine the entries
* @see #combine(SessionContext, Appendable, char, KeyIdentityProvider)
*/
public static String combine(
SessionContext session, char separator, KeyIdentityProvider provider)
throws Exception {
return combine(session, new StringBuilder(4 * (FLDSIZE_X + 4) * (FLDSIZE_Y + 3)), separator, provider).toString();
}
/**
* Appends the combined random art entries for the provided keys
*
* @param The {@link Appendable} output writer
* @param session The {@link SessionContext} for invoking this load command - may be {@code null} if not invoked
* within a session context (e.g., offline tool or session unknown).
* @param sb The writer
* @param separator The separator to use between the arts - if empty char ('\0') then no separation is done
* @param provider The {@link KeyIdentityProvider} - ignored if {@code null} or has no keys to provide
* @return The updated writer instance
* @throws Exception If failed to extract or write the entries
* @see #generate(SessionContext, KeyIdentityProvider)
* @see #combine(Appendable, char, Collection)
*/
public static A combine(
SessionContext session, A sb, char separator, KeyIdentityProvider provider)
throws Exception {
return combine(sb, separator, generate(session, provider));
}
/**
* Extracts and generates random art entries for all key in the provider
*
* @param session The {@link SessionContext} for invoking this load command - may be {@code null} if not invoked
* within a session context (e.g., offline tool or session unknown).
* @param provider The {@link KeyIdentityProvider} - ignored if {@code null} or has no keys to provide
* @return The extracted {@link KeyRandomArt}s
* @throws Exception If failed to extract the entries
* @see KeyIdentityProvider#loadKeys(SessionContext)
*/
public static Collection generate(
SessionContext session, KeyIdentityProvider provider)
throws Exception {
Iterable keys = (provider == null) ? null : provider.loadKeys(session);
Iterator iter = (keys == null) ? null : keys.iterator();
if ((iter == null) || (!iter.hasNext())) {
return Collections.emptyList();
}
Collection arts = new LinkedList<>();
do {
KeyPair kp = iter.next();
KeyRandomArt a = new KeyRandomArt(kp.getPublic());
arts.add(a);
} while (iter.hasNext());
return arts;
}
/**
* Combines the arts in a user-friendly way so they are aligned with each other
*
* @param The {@link Appendable} output writer
* @param sb The writer
* @param separator The separator to use between the arts - if empty char ('\0') then no separation is done
* @param arts The {@link KeyRandomArt}s to combine - ignored if {@code null}/empty
* @return The updated writer instance
* @throws IOException If failed to write the combined result
*/
public static A combine(A sb, char separator, Collection arts)
throws IOException {
if (GenericUtils.isEmpty(arts)) {
return sb;
}
List allLines = new ArrayList<>(arts.size());
int numLines = -1;
for (KeyRandomArt a : arts) {
String s = a.toString();
String[] lines = GenericUtils.split(s, '\n');
if (numLines <= 0) {
numLines = lines.length;
} else {
if (numLines != lines.length) {
throw new StreamCorruptedException(
"Mismatched lines count: expected=" + numLines + ", actual=" + lines.length);
}
}
for (int index = 0; index < lines.length; index++) {
String l = lines[index];
if ((l.length() > 0) && (l.charAt(l.length() - 1) == '\r')) {
l = l.substring(0, l.length() - 1);
lines[index] = l;
}
}
allLines.add(lines);
}
for (int row = 0; row < numLines; row++) {
for (int index = 0; index < allLines.size(); index++) {
String[] lines = allLines.get(index);
String l = lines[row];
sb.append(l);
if ((index > 0) && (separator != '\0')) {
sb.append(separator);
}
}
sb.append('\n');
}
return sb;
}
}