需要安全的密码生成器推荐

Question

任何人都可以推荐使用Apache或LGPL许可证下的Java安全密码生成器吗？

Answer 1

我不会担心产生令人难以置信的强大的一次性密码.将密码设置得很长,并且在强制密码有效期限的情况下使用暴力不应该是一个问题.如果密码仅在1小时内有效,那么如果密码仍然未使用则不会有问题.在那段时间内,有人不太可能使用蛮力破解它.

同样重要的是,您只需让一次性密码工作一次.这样,如果密码被截获,用户将注意到一次性密码何时到期并且可以采取适当的操作.

我会去Apache Commons RandomStringUtils,密码是10-15个字母和数字.

......虽然这总是一个你想成为多么偏执的问题.这个解决方案适用于常规Web应用程序,但对银行来说还不够好......

Answer 2

它在.net中,但转换应该是微不足道的.对大多数人来说可能有点太多了,但这是我在我的应用程序中总是使用的实现.这是我前段时间发现的一个实现,并做了一些修改,我不记得原作者,但我会快速搜索一下,看看我是否可以给他适当的信用.

public static string GenerateRandomString(int minLength, int maxLength, int minLCaseCount, int minUCaseCount, int minNumCount, int minSpecialCount)
        {
            char[] randomString;

            const string LCaseChars = "abcdefgijkmnopqrstwxyz";
            const string UCaseChars = "ABCDEFGHJKLMNPQRSTWXYZ";
            const string NumericChars = "23456789";
            const string SpecialChars = "*$-+?_&=!%{}/";

            Hashtable charGroupsUsed = new Hashtable();
            charGroupsUsed.Add("lcase", minLCaseCount);
            charGroupsUsed.Add("ucase", minUCaseCount);
            charGroupsUsed.Add("num", minNumCount);
            charGroupsUsed.Add("special", minSpecialCount);

            // 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 = (randomBytes[0] & 0x7f) << 24 |
                        randomBytes[1] << 16 |
                        randomBytes[2] << 8 |
                        randomBytes[3];

            // Create a randomizer from the seed.
            Random random = new Random(seed);

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

            int requiredCharactersLeft = minLCaseCount + minUCaseCount + minNumCount + minSpecialCount;

            // Build the password.
            for (int i = 0; i < randomString.Length; i++)
            {
                string selectableChars = "";

                // if we still have plenty of characters left to acheive our minimum requirements.
                if (requiredCharactersLeft < randomString.Length - i)
                {
                    // choose from any group at random
                    selectableChars = LCaseChars + UCaseChars + NumericChars + SpecialChars;
                }
                else // we are out of wiggle room, choose from a random group that still needs to have a minimum required.
                {
                    // choose only from a group that we need to satisfy a minimum for.
                    foreach (DictionaryEntry charGroup in charGroupsUsed)
                    {
                        if ((int)charGroup.Value > 0)
                        {
                            switch (charGroup.Key.ToString())
                            {
                                case "lcase":
                                    selectableChars += LCaseChars;
                                    break;
                                case "ucase":
                                    selectableChars += UCaseChars;
                                    break;
                                case "num":
                                    selectableChars += NumericChars;
                                    break;
                                case "special":
                                    selectableChars += SpecialChars;
                                    break;
                            }
                        }
                    }
                }

                // Now that the string is built, get the next random character.
                char nextChar = selectableChars[random.Next(0, selectableChars.Length - 1)];

                // Tac it onto our password.
                randomString[i] = nextChar;

                // Now figure out where it came from, and decrement the appropriate minimum value.
                if (LCaseChars.Contains(nextChar))
                {
                    charGroupsUsed["lcase"] = (int)charGroupsUsed["lcase"] - 1;
                    if ((int)charGroupsUsed["lcase"] >= 0)
                    {
                        requiredCharactersLeft--;
                    }
                }
                else if (UCaseChars.Contains(nextChar))
                {
                    charGroupsUsed["ucase"] = (int)charGroupsUsed["ucase"] - 1;
                    if ((int)charGroupsUsed["ucase"] >= 0)
                    {
                        requiredCharactersLeft--;
                    }
                }
                else if (NumericChars.Contains(nextChar))
                {
                    charGroupsUsed["num"] = (int)charGroupsUsed["num"] - 1;
                    if ((int)charGroupsUsed["num"] >= 0)
                    {
                        requiredCharactersLeft--;
                    }
                }
                else if (SpecialChars.Contains(nextChar))
                {
                    charGroupsUsed["special"] = (int)charGroupsUsed["special"] - 1;
                    if ((int)charGroupsUsed["special"] >= 0)
                    {
                        requiredCharactersLeft--;
                    }
                }
            }
            return new string(randomString);
        }

编辑

我相信我开始使用http://www.obviex.com/Samples/Password.aspx上发布的代码 .虽然代码现在还有一些功能.