在java中生成具有大量限制的随机密码 [英] generating random password with lot of restriction in java
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问题描述
我想创建一个密码生成器，根据用户设置的限制创建密码。限制条件是：
I would like to create a password generator that create password according to the restriction set by user. The restrictions is:
- 最小密码长度
- 最大密码长度
- 最小字母和数字
- 最低信件
- 最小大写字母
- 最小小写字母
- 最小数字
- 最大重复字符
- Minimum Password Length
- Maximum Password Length
- Minimum Letter And Digit
- Minimum Letter
- Minimum Uppercase Letter
- Minimum Lowercase Letter
- Minimum Digit
- Maximum Repeat Character
I通过谷歌了望，大多数示例代码都不符合我的要求。所以我即兴发布这样的代码：
I lookout through google and most of the example code doesn't meet the requirement that I need. So I improvise the code like this:
private char[] GeneratePassword(int minLength, int maxLength,
int maxRepeatCharacter, int minLetterAndDigit, int minLetter,
int minLowerCaseLetter, int minUpperCaseLetter, int minDigit) {
final String LETTER = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ";
final String UPPERCASE = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
final String LOWERCASE = "abcdefghijklmnopqrstuvwxyz";
final String DIGIT = "0123456789";
final String[] randomSelector = {LETTER,UPPERCASE,LOWERCASE,DIGIT};
int len = getRandomNumber(minLength, maxLength);
char[] passwordGenerated = new char[len];
char[] characterUsed = new char[len];
int selection;
int letterAndDigitUsed = 0;
int letterUsed = 0;
int lowerCaseLetterUsed = 0;
int upperCaseLetterUsed = 0;
int digitUsed = 0;
int index = 0;
if (minLength > maxLength) {
// throw new IllegalArgumentException("Min.Length > Max.Length!");
}
if (minLetter + minDigit > minLetterAndDigit) {
// throw new IllegalArgumentException("Error!");
}
while (index != len) {
selection = getRandomNumber(0, randomSelector.length);
if (selection == 0) {
passwordGenerated[index] = LETTER.charAt(RandomUtils.nextInt(0,
LETTER.length()));
if (checkRepeatCharacter(passwordGenerated[index],
characterUsed, index, maxRepeatCharacter) == false) {
characterUsed[index] = passwordGenerated[index];
index++;
letterUsed++;
letterAndDigitUsed++;
break;
}
} else if (selection == 1) {
passwordGenerated[index] = UPPERCASE.charAt(RandomUtils
.nextInt(0, UPPERCASE.length()));
if (checkRepeatCharacter(passwordGenerated[index],
characterUsed, index, maxRepeatCharacter) == false) {
characterUsed[index] = passwordGenerated[index];
index++;
upperCaseLetterUsed++;
letterAndDigitUsed++;
break;
}
} else if (selection == 2) {
passwordGenerated[index] = LOWERCASE.charAt(RandomUtils
.nextInt(0, LOWERCASE.length()));
if (checkRepeatCharacter(passwordGenerated[index],
characterUsed, index, maxRepeatCharacter) == false) {
characterUsed[index] = passwordGenerated[index];
index++;
lowerCaseLetterUsed++;
letterAndDigitUsed++;
break;
}
} else if (selection == 3) {
passwordGenerated[index] = DIGIT.charAt(RandomUtils.nextInt(0,
DIGIT.length()));
if (checkRepeatCharacter(passwordGenerated[index],
characterUsed, index, maxRepeatCharacter) == false) {
characterUsed[index] = passwordGenerated[index];
index++;
digitUsed++;
letterAndDigitUsed++;
break;
}
}
}
return passwordGenerated;
}
private boolean checkRepeatCharacter(char passwordGenerated,
char[] passwordUsed, int index, int maxRepeatCharacter) {
int characterRepeated = 0;
for (int i = 0; i < index; i++) {
if (String.valueOf(passwordUsed[i]).equals(
String.valueOf(passwordGenerated))) {
characterRepeated++;
if (characterRepeated == maxRepeatCharacter) {
return true;
}
}
}
return false;
}
private int getRandomNumber(int minLength, int maxLength) {
Random r = new Random();
return r.nextInt(maxLength - minLength) + minLength;
}
我遇到的问题是如何确保满足最低条件。同时，我不希望通过重复使用相同类型的字符来生成密码。
The problem that I'm having is how to ensure the minimum condition are met. At the same time, I dont want my password to be generated by repeating at the same type of character.
-
示例：如果我把我的最大密码长度设置为10，我希望最小数字为5.我更喜欢
1jP2k3o4m9而不是57812aJ9tP。
第二个示例：如果我将最大密码长度设置为5，并且我希望最小小写字母为3.我更喜欢 Pj9mn 而不是 jkl5V 。
2nd Example: If I put my maximum password length to 5 and I want a minimum lowercase letter of 3. I prefer to have Pj9mn rather than jkl5V.
如您所见，第二个生成的密码首先尝试满足最低要求，然后只对其他字符类型进行随机选择。这将使密码更容易受到攻击。有没有办法做这个算法。
As you can see, the 2nd generated password is trying to fullfill the minimum requirement first, then only do a random selection to other character type. Which will make the password more vulnerable. Is there any way to do this algorithm.
推荐答案
我修复了我的代码。到目前为止，我已经测试过，我可以根据需要完美运行。我留下这段代码以防其他人将来需要它。
I have fixed my code. So far I've tested, I works perfectly as required. I leave this code just in case someone else need it in the future.
private boolean checkRepeatCharacter(char randomCharacter,
ArrayList<Character> passwordUsed, int usedLength,
int maxRepeatCharacter) {
int characterRepeated = 0;
for (int i = 0; i < usedLength; i++) {
if (String.valueOf(passwordUsed.get(i)).equals(
String.valueOf(randomCharacter))) {
characterRepeated++;
if (characterRepeated == maxRepeatCharacter) {
return false;
}
}
}
return true;
}
private boolean checkUsedIndex(int index, ArrayList<Integer> usedIndex) {
for (int i = 0; i < usedIndex.size(); i++) {
if (usedIndex.contains(index)) {
return false;
}
}
return true;
}
private int getRandomNumber(int minLength, int maxLength) {
Random r = new Random();
return r.nextInt(maxLength - minLength) + minLength;
}
public String generatePassword(int minLength, int maxLength,
int maxRepeatCharacter, int minLetterAndDigit, int minLetter,
int minLowerCaseLetter, int minUpperCaseLetter, int minDigit,
int minSpecialCharacter, String specialCharacter) {
final String LOWERCASE = "abcdefghijklmnopqrstuvwxyz";
final String UPPERCASE = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
final String DIGIT = "0123456789";
StringBuilder ALL = new StringBuilder();
ALL.append(LOWERCASE);
ALL.append(UPPERCASE);
ALL.append(DIGIT);
ALL.append(specialCharacter);
ALL.toString();
char getRandom;
int length = 0;
StringBuilder passwordGenerated = new StringBuilder();
ArrayList<Character> characterUsed = new ArrayList<Character>();
ArrayList<Integer> indexUsed = new ArrayList<Integer>();
int passwordLength = 0;
int lowerCaseLetterUsed = 0;
int upperCaseLetterUsed = 0;
int letterUsed = 0;
int digitUsed = 0;
int letterAndDigitUsed = 0;
int specialCharacterUsed = 0;
if (minLength > maxLength) {
throw new IllegalArgumentException("Min. Length > Max. Length!");
}
if (minUpperCaseLetter + minLowerCaseLetter > minLetter) {
throw new RuntimeException(
"mininimum Lower Case + Minimum Uppercase cannot exceed minLetter");
}
if (minLetter + minDigit > minLetterAndDigit) {
throw new RuntimeException(
"mininimum Letter + Minimum Digit cannot exceed minimum Letter And Digit");
}
if (minLetter + minDigit + minSpecialCharacter > maxLength) {
throw new RuntimeException(
"minimum Digit + minimum Letter + Minimum Special Character cannot excced maximum Length");
}
while ((length < minLetter) && (length < minLetterAndDigit)) {
length = getRandomNumber(minLength, maxLength);
}
while (passwordLength != length) {
while (letterAndDigitUsed < minLetterAndDigit) {
while (letterUsed < minLetter) {
lowerCaseLetterUsed = 0;
for (int i = 0; lowerCaseLetterUsed < minLowerCaseLetter; i++) {
int index = getRandomNumber(0, length);
if (checkUsedIndex(index, indexUsed) == true) {
getRandom = LOWERCASE.charAt(getRandomNumber(0,
LOWERCASE.length()));
if (checkRepeatCharacter(getRandom, characterUsed,
characterUsed.size(), maxRepeatCharacter) == true) {
passwordGenerated.append(getRandom);
characterUsed.add(getRandom);
indexUsed.add(index);
lowerCaseLetterUsed++;
letterUsed++;
letterAndDigitUsed++;
passwordLength++;
if (letterUsed == minLetter) {
break;
}
}
}
}
if (letterAndDigitUsed == minLetterAndDigit) {
break;
}
upperCaseLetterUsed = 0;
for (int i = 0; upperCaseLetterUsed < minUpperCaseLetter; i++) {
int index = getRandomNumber(0, length);
if (checkUsedIndex(index, indexUsed) == true) {
getRandom = UPPERCASE.charAt(getRandomNumber(0,
UPPERCASE.length()));
if (checkRepeatCharacter(getRandom, characterUsed,
characterUsed.size(), maxRepeatCharacter) == true) {
passwordGenerated.append(getRandom);
characterUsed.add(getRandom);
indexUsed.add(index);
lowerCaseLetterUsed++;
letterUsed++;
letterAndDigitUsed++;
passwordLength++;
if (letterUsed == minLetter) {
break;
}
}
}
}
if (letterAndDigitUsed == minLetterAndDigit) {
break;
}
}
for (int i = 0; digitUsed < minDigit; i++) {
int index = getRandomNumber(0, length);
if (checkUsedIndex(index, indexUsed) == true) {
getRandom = DIGIT.charAt(getRandomNumber(0,
DIGIT.length()));
if (checkRepeatCharacter(getRandom, characterUsed,
characterUsed.size(), maxRepeatCharacter) == true) {
passwordGenerated.append(getRandom);
characterUsed.add(getRandom);
indexUsed.add(index);
digitUsed++;
letterAndDigitUsed++;
passwordLength++;
}
}
}
}
for (int i = 0; specialCharacterUsed < minSpecialCharacter; i++) {
if (checkUsedIndex(i, indexUsed) == true) {
getRandom = specialCharacter.charAt(getRandomNumber(0,
specialCharacter.length()));
if (checkRepeatCharacter(getRandom, characterUsed,
characterUsed.size(), maxRepeatCharacter) == true) {
passwordGenerated.append(getRandom);
characterUsed.add(getRandom);
indexUsed.add(i);
specialCharacterUsed++;
passwordLength++;
}
}
}
for (int i = 0; i < length; i++) {
if (checkUsedIndex(i, indexUsed) == true) {
getRandom = ALL.charAt(getRandomNumber(0, ALL.length()));
if (checkRepeatCharacter(getRandom, characterUsed,
characterUsed.size(), maxRepeatCharacter) == true) {
passwordGenerated.append(getRandom);
characterUsed.add(getRandom);
indexUsed.add(i);
passwordLength++;
}
}
}
}
return passwordGenerated.toString();
}
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