b8e2f5fe1d
- Improve RandomString and create new generateLowerUpper method - Add documentation to the IPB4 class to explain why the salt is stored twice
63 lines
2.0 KiB
Java
63 lines
2.0 KiB
Java
package fr.xephi.authme.security;
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import java.security.SecureRandom;
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import java.util.Random;
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/**
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* Utility for generating random strings.
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*/
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public final class RandomString {
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private static final String CHARS = "0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ";
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private static final Random RANDOM = new SecureRandom();
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private static final int HEX_MAX_INDEX = 16;
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private static final int LOWER_ALPHANUMERIC_INDEX = 36;
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private RandomString() {
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}
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/**
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* Generate a string of the given length consisting of random characters within the range [0-9a-z].
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*
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* @param length The length of the random string to generate
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* @return The random string
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*/
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public static String generate(int length) {
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return generate(length, LOWER_ALPHANUMERIC_INDEX);
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}
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/**
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* Generate a random hexadecimal string of the given length. In other words, the generated string
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* contains characters only within the range [0-9a-f].
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*
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* @param length The length of the random string to generate
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* @return The random hexadecimal string
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*/
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public static String generateHex(int length) {
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return generate(length, HEX_MAX_INDEX);
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}
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/**
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* Generate a random string with digits and lowercase and uppercase letters. The result of this
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* method matches the pattern [0-9a-zA-Z].
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*
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* @param length The length of the random string to generate
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* @return The random string
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*/
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public static String generateLowerUpper(int length) {
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return generate(length, CHARS.length());
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}
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private static String generate(int length, int maxIndex) {
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if (length < 0) {
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throw new IllegalArgumentException("Length must be positive but was " + length);
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}
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StringBuilder sb = new StringBuilder(length);
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for (int i = 0; i < length; ++i) {
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sb.append(CHARS.charAt(RANDOM.nextInt(maxIndex)));
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}
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return sb.toString();
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}
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}
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