首页
学习
活动
专区
工具
TVP
发布
社区首页 >问答首页 >生成随机密码?

生成随机密码?
EN

Stack Overflow用户
提问于 2018-06-12 04:51:13
回答 2查看 0关注 0票数 0

当我们网站上的用户丢失密码并前往丢失密码页面时,我们需要给他一个新的临时密码。我真的不介意这是多么随意,或者如果它匹配所有“需要”强密码规则,我想要做的就是给他们一个密码,以便以后可以更改。

该应用程序是用C#编写的Web应用程序。所以我在考虑是否意味着要使用Guid的一部分的简单途径。即

代码语言:javascript
复制
Guid.NewGuid().ToString("d").Substring(1,8)
EN

回答 2

Stack Overflow用户

发布于 2018-06-12 13:08:07

我知道这是一个古老的线索,但我有什么可能是一个相当简单的解决方案供某人使用。易于实施,易于理解并易于验证。

考虑以下要求:

我需要生成一个随机密码,它至少包含2个小写字母,2个大写字母和2个数字。密码长度不得少于8个字符。

以下正则表达式可以验证这种情况:

代码语言:javascript
复制
^(?=\b\w*[a-z].*[a-z]\w*\b)(?=\b\w*[A-Z].*[A-Z]\w*\b)(?=\b\w*[0-9].*[0-9]\w*\b)[a-zA-Z0-9]{8,}$

这超出了这个问题的范围 - 但是正则表达式是基于前瞻/后视和环视。

以下代码将创建一组符合此要求的随机字符集:

代码语言:javascript
复制
public static string GeneratePassword(int lowercase, int uppercase, int numerics) {
    string lowers = "abcdefghijklmnopqrstuvwxyz";
    string uppers = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
    string number = "0123456789";

    Random random = new Random();

    string generated = "!";
    for (int i = 1; i <= lowercase; i++)
        generated = generated.Insert(
            random.Next(generated.Length), 
            lowers[random.Next(lowers.Length - 1)].ToString()
        );

    for (int i = 1; i <= uppercase; i++)
        generated = generated.Insert(
            random.Next(generated.Length), 
            uppers[random.Next(uppers.Length - 1)].ToString()
        );

    for (int i = 1; i <= numerics; i++)
        generated = generated.Insert(
            random.Next(generated.Length), 
            number[random.Next(number.Length - 1)].ToString()
        );

    return generated.Replace("!", string.Empty);

}

要满足上述要求,只需:

代码语言:javascript
复制
String randomPassword = GeneratePassword(3, 3, 3);

代码以一个无效的字符("!")开始 - 这样字符串的长度就可以被注入新的字符。

然后从1循环到需要的小写字符数量,并且在每次迭代时,从小写列表中抓取一个随机项目,并将其注入字符串中的随机位置。

然后它重复大写字母和数字的循环。

这会给你返回长度=的字符串,lowercase + uppercase + numerics你想要的计数的小写字母,大写字母和数字字符以随机顺序排列。

票数 0
EN

Stack Overflow用户

发布于 2018-06-12 14:27:45

这是更大,但我认为它看起来更全面:http//www.obviex.com/Samples/Password.aspx

代码语言:javascript
复制
///////////////////////////////////////////////////////////////////////////////
// SAMPLE: Generates random password, which complies with the strong password
//         rules and does not contain ambiguous characters.
//
// To run this sample, create a new Visual C# project using the Console
// Application template and replace the contents of the Class1.cs file with
// the code below.
//
// THIS CODE AND INFORMATION IS PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND,
// EITHER EXPRESSED OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE IMPLIED
// WARRANTIES OF MERCHANTABILITY AND/OR FITNESS FOR A PARTICULAR PURPOSE.
// 
// Copyright (C) 2004 Obviex(TM). All rights reserved.
// 
using System;
using System.Security.Cryptography;

/// <summary>
/// This class can generate random passwords, which do not include ambiguous 
/// characters, such as I, l, and 1. The generated password will be made of
/// 7-bit ASCII symbols. Every four characters will include one lower case
/// character, one upper case character, one number, and one special symbol
/// (such as '%') in a random order. The password will always start with an
/// alpha-numeric character; it will not start with a special symbol (we do
/// this because some back-end systems do not like certain special
/// characters in the first position).
/// </summary>
public class RandomPassword
{
    // Define default min and max password lengths.
    private static int DEFAULT_MIN_PASSWORD_LENGTH  = 8;
    private static int DEFAULT_MAX_PASSWORD_LENGTH  = 10;

    // Define supported password characters divided into groups.
    // You can add (or remove) characters to (from) these groups.
    private static string PASSWORD_CHARS_LCASE  = "abcdefgijkmnopqrstwxyz";
    private static string PASSWORD_CHARS_UCASE  = "ABCDEFGHJKLMNPQRSTWXYZ";
    private static string PASSWORD_CHARS_NUMERIC= "23456789";
    private static string PASSWORD_CHARS_SPECIAL= "*$-+?_&=!%{}/";

    /// <summary>
    /// Generates a random password.
    /// </summary>
    /// <returns>
    /// Randomly generated password.
    /// </returns>
    /// <remarks>
    /// The length of the generated password will be determined at
    /// random. It will be no shorter than the minimum default and
    /// no longer than maximum default.
    /// </remarks>
    public static string Generate()
    {
        return Generate(DEFAULT_MIN_PASSWORD_LENGTH, 
                        DEFAULT_MAX_PASSWORD_LENGTH);
    }

    /// <summary>
    /// Generates a random password of the exact length.
    /// </summary>
    /// <param name="length">
    /// Exact password length.
    /// </param>
    /// <returns>
    /// Randomly generated password.
    /// </returns>
    public static string Generate(int length)
    {
        return Generate(length, length);
    }

    /// <summary>
    /// Generates a random password.
    /// </summary>
    /// <param name="minLength">
    /// Minimum password length.
    /// </param>
    /// <param name="maxLength">
    /// Maximum password length.
    /// </param>
    /// <returns>
    /// Randomly generated password.
    /// </returns>
    /// <remarks>
    /// The length of the generated password will be determined at
    /// random and it will fall with the range determined by the
    /// function parameters.
    /// </remarks>
    public static string Generate(int   minLength,
                                  int   maxLength)
    {
        // Make sure that input parameters are valid.
        if (minLength <= 0 || maxLength <= 0 || minLength > maxLength)
            return null;

        // Create a local array containing supported password characters
        // grouped by types. You can remove character groups from this
        // array, but doing so will weaken the password strength.
        char[][] charGroups = new char[][] 
        {
            PASSWORD_CHARS_LCASE.ToCharArray(),
            PASSWORD_CHARS_UCASE.ToCharArray(),
            PASSWORD_CHARS_NUMERIC.ToCharArray(),
            PASSWORD_CHARS_SPECIAL.ToCharArray()
        };

        // Use this array to track the number of unused characters in each
        // character group.
        int[] charsLeftInGroup = new int[charGroups.Length];

        // Initially, all characters in each group are not used.
        for (int i=0; i<charsLeftInGroup.Length; i++)
            charsLeftInGroup[i] = charGroups[i].Length;

        // Use this array to track (iterate through) unused character groups.
        int[] leftGroupsOrder = new int[charGroups.Length];

        // Initially, all character groups are not used.
        for (int i=0; i<leftGroupsOrder.Length; i++)
            leftGroupsOrder[i] = i;

        // Because we cannot use the default randomizer, which is based on the
        // current time (it will produce the same "random" number within a
        // second), we will use a random number generator to seed the
        // randomizer.

        // Use a 4-byte array to fill it with random bytes and convert it then
        // to an integer value.
        byte[] randomBytes = new byte[4];

        // Generate 4 random bytes.
        RNGCryptoServiceProvider rng = new RNGCryptoServiceProvider();
        rng.GetBytes(randomBytes);

        // Convert 4 bytes into a 32-bit integer value.
        int seed = BitConverter.ToInt32(randomBytes, 0);

        // Now, this is real randomization.
        Random  random  = new Random(seed);

        // This array will hold password characters.
        char[] password = null;

        // Allocate appropriate memory for the password.
        if (minLength < maxLength)
            password = new char[random.Next(minLength, maxLength+1)];
        else
            password = new char[minLength];

        // Index of the next character to be added to password.
        int nextCharIdx;

        // Index of the next character group to be processed.
        int nextGroupIdx;

        // Index which will be used to track not processed character groups.
        int nextLeftGroupsOrderIdx;

        // Index of the last non-processed character in a group.
        int lastCharIdx;

        // Index of the last non-processed group.
        int lastLeftGroupsOrderIdx = leftGroupsOrder.Length - 1;

        // Generate password characters one at a time.
        for (int i=0; i<password.Length; i++)
        {
            // If only one character group remained unprocessed, process it;
            // otherwise, pick a random character group from the unprocessed
            // group list. To allow a special character to appear in the
            // first position, increment the second parameter of the Next
            // function call by one, i.e. lastLeftGroupsOrderIdx + 1.
            if (lastLeftGroupsOrderIdx == 0)
                nextLeftGroupsOrderIdx = 0;
            else
                nextLeftGroupsOrderIdx = random.Next(0, 
                                                     lastLeftGroupsOrderIdx);

            // Get the actual index of the character group, from which we will
            // pick the next character.
            nextGroupIdx = leftGroupsOrder[nextLeftGroupsOrderIdx];

            // Get the index of the last unprocessed characters in this group.
            lastCharIdx = charsLeftInGroup[nextGroupIdx] - 1;

            // If only one unprocessed character is left, pick it; otherwise,
            // get a random character from the unused character list.
            if (lastCharIdx == 0)
                nextCharIdx = 0;
            else
                nextCharIdx = random.Next(0, lastCharIdx+1);

            // Add this character to the password.
            password[i] = charGroups[nextGroupIdx][nextCharIdx];

            // If we processed the last character in this group, start over.
            if (lastCharIdx == 0)
                charsLeftInGroup[nextGroupIdx] = 
                                          charGroups[nextGroupIdx].Length;
            // There are more unprocessed characters left.
            else
            {
                // Swap processed character with the last unprocessed character
                // so that we don't pick it until we process all characters in
                // this group.
                if (lastCharIdx != nextCharIdx)
                {
                    char temp = charGroups[nextGroupIdx][lastCharIdx];
                    charGroups[nextGroupIdx][lastCharIdx] = 
                                charGroups[nextGroupIdx][nextCharIdx];
                    charGroups[nextGroupIdx][nextCharIdx] = temp;
                }
                // Decrement the number of unprocessed characters in
                // this group.
                charsLeftInGroup[nextGroupIdx]--;
            }

            // If we processed the last group, start all over.
            if (lastLeftGroupsOrderIdx == 0)
                lastLeftGroupsOrderIdx = leftGroupsOrder.Length - 1;
            // There are more unprocessed groups left.
            else
            {
                // Swap processed group with the last unprocessed group
                // so that we don't pick it until we process all groups.
                if (lastLeftGroupsOrderIdx != nextLeftGroupsOrderIdx)
                {
                    int temp = leftGroupsOrder[lastLeftGroupsOrderIdx];
                    leftGroupsOrder[lastLeftGroupsOrderIdx] = 
                                leftGroupsOrder[nextLeftGroupsOrderIdx];
                    leftGroupsOrder[nextLeftGroupsOrderIdx] = temp;
                }
                // Decrement the number of unprocessed groups.
                lastLeftGroupsOrderIdx--;
            }
        }

        // Convert password characters into a string and return the result.
        return new string(password);
     }
}

/// <summary>
/// Illustrates the use of the RandomPassword class.
/// </summary>
public class RandomPasswordTest
{
    /// <summary>
    /// The main entry point for the application.
    /// </summary>
    [STAThread]
    static void Main(string[] args)
    {
        // Print 100 randomly generated passwords (8-to-10 char long).
        for (int i=0; i<100; i++)
            Console.WriteLine(RandomPassword.Generate(8, 10));
    }
}
//
// END OF FILE
///////////////////////////////////////////////////////////////////////////////
票数 0
EN
页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持
原文链接:

https://stackoverflow.com/questions/-100000257

复制
相关文章

相似问题

领券
问题归档专栏文章快讯文章归档关键词归档开发者手册归档开发者手册 Section 归档