hash("hello") = 2cf24dba5fb0a30e26e83b2ac5b9e29e1b161e5c1fa7425e73043362938b9824hash("hbllo") = 58756879c05c68dfac9866712fad6a93f8146f337a69afe7dd238f3364946366hash("waltz") = c0e81794384491161f1777c232bc6bd9ec38f616560b120fda8e90f383853542
Hash算法是一种单向的函数。它可以把任意数量的数据转换成固定长度的“指纹”，这个过程是不可逆的。而且只要输入发生改变，哪怕只有一个bit，输出的hash值也会有很大不同。这种特性恰好合适用来用来保存密码。因为我们希望使用一种不可逆的算法来加密保存的密码，同时又需要在用户登陆的时候验证密码是否正确。在一个使用hash的账号系统中，用户注册和认证的大致流程如下：
用户创建自己的账号
用户密码经过hash操作之后存储在数据库中。没有任何明文的密码存储在服务器的硬盘上。
用户登陆的时候，将用户输入的密码进行hash操作后与数据库里保存的密码hash值进行对比。
如果hash值完全一样，则认为用户输入的密码是正确的。否则就认为用户输入了无效的密码。
每次用户尝试登陆的时候就重复步骤3和步骤4。
在步骤4的时候不要告诉用户是账号还是密码错了。只需要显示一个通用的提示，比如账号或密码不正确就可以了。这样可以防止攻击者枚举有效的用户名。还需要注意的是用来保护密码的hash函数跟数据结构课上见过的hash函数不完全一样。比如实现hash表的hash函数设计的目的是快速，但是不够安全。只有加密hash函数(cryptographic hash functions)可以用来进行密码的hash。这样的函数有SHA256, SHA512, RipeMD, WHIRLPOOL等。一个常见的观念就是密码经过hash之后存储就安全了。这显然是不正确的。有很多方式可以快速的从hash恢复明文的密码。还记得那些md5破解网站吧，只需要提交一个hash，不到一秒钟就能知道结果。显然，单纯的对密码进行hash还是远远达不到我们的安全需求。下一部分先讨论一下破解密码hash，获取明文常见的手段。如何破解hash字典和暴力破解攻击(Dictionary and Brute Force Attacks)最常见的破解hash手段就是猜测密码。然后对每一个可能的密码进行hash，对比需要破解的hash和猜测的密码hash值，如果两个值一样，那么之前猜测的密码就是正确的密码明文。猜测密码攻击常用的方式就是字典攻击和暴力攻击。
Dictionary AttackTrying apple : failedTrying blueberry : failedTrying justinbeiber : failed...Trying letmein : failedTrying s3cr3t : success!
字典攻击是将常用的密码，单词，短语和其他可能用来做密码的字符串放到一个文件中，然后对文件中的每一个词进行hash，将这些hash与需要破解的密码hash比较。这种方式的成功率取决于密码字典的大小以及字典的是否合适。
Brute Force AttackTrying aaaa : failedTrying aaab : failedTrying aaac : failed...Trying acdb : failedTrying acdc : success!
暴力攻击就是对于给定的密码长度，尝试每一种可能的字符组合。这种方式需要花费大量的计算机时间。但是理论上只要时间足够，最后密码一定能够破解出来。只是如果密码太长，破解花费的时间就会大到无法承受。目前没有方式可以阻止字典攻击和暴力攻击。只能想办法让它们变的低效。如果你的密码hash系统设计的是安全的，那么破解hash唯一的方式就是进行字典或者暴力攻击了。查表破解(Lookup Tables)对于特定的hash类型，如果需要破解大量hash的话，查表是一种非常有效而且快速的方式。它的理念就是预先计算(pre-compute)出密码字典中每一个密码的hash。然后把hash和对应的密码保存在一个表里。一个设计良好的查询表结构，即使存储了数十亿个hash，每秒钟仍然可以查询成百上千个hash。如果你想感受下查表破解hash的话可以尝试一下在CraskStation上破解下下面的sha256 hash。
c11083b4b0a7743af748c85d343dfee9fbb8b2576c05f3a7f0d632b0926aadfc08eac03b80adc33dc7d8fbe44b7c7b05d3a2c511166bdb43fcb710b03ba919e7e4ba5cbd251c98e6cd1c23f126a3b81d8d8328abc95387229850952b3ef9f9045206b8b8a996cf5320cb12ca91c7b790fba9f030408efe83ebb83548dc3007bd
反向查表破解(Reverse Lookup Tables)
Searching for hash(apple) in users' hash list... : Matches [alice3, 0bob0, charles8]Searching for hash(blueberry) in users' hash list... : Matches [usr10101, timmy, john91]Searching for hash(letmein) in users' hash list... : Matches [wilson10, dragonslayerX, joe1984]Searching for hash(s3cr3t) in users' hash list... : Matches [bruce19, knuth1337, john87]Searching for hash(z@29hjja) in users' hash list... : No users used this password
这种方式可以让攻击者不预先计算一个查询表的情况下同时对大量hash进行字典和暴力破解攻击。首先，攻击者会根据获取到的数据库数据制作一个用户名和对应的hash表。然后将常见的字典密码进行hash之后，跟这个表的hash进行对比，就可以知道用哪些用户使用了这个密码。这种攻击方式很有效果，因为通常情况下很多用户都会有使用相同的密码。彩虹表 (Rainbow Tables)彩虹表是一种使用空间换取时间的技术。跟查表破解很相似。只是它牺牲了一些破解时间来达到更小的存储空间的目的。因为彩虹表使用的存储空间更小，所以单位空间就可以存储更多的hash。彩虹表已经能够破解8位长度的任意md5hash。彩虹表具体的原理可以参考http://www.project-rainbowcrack.com/下一章节我们会讨论一种叫做“盐”(salting)的技术。通过这种技术可以让查表和彩虹表的方式无法破解hash。加盐(Adding Salt)
hash("hello") = 2cf24dba5fb0a30e26e83b2ac5b9e29e1b161e5c1fa7425e73043362938b9824hash("hello" + "QxLUF1bgIAdeQX") = 9e209040c863f84a31e719795b2577523954739fe5ed3b58a75cff2127075ed1hash("hello" + "bv5PehSMfV11Cd") = d1d3ec2e6f20fd420d50e2642992841d8338a314b8ea157c9e18477aaef226abhash("hello" + "YYLmfY6IehjZMQ") = a49670c3c18b9e079b9cfaf51634f563dc8ae3070db2c4a8544305df1b60f007
md5(sha1(password))md5(md5(salt) + md5(password))sha1(sha1(password))sha1(str_rot13(password + salt))md5(sha1(md5(md5(password) + sha1(password)) + md5(password)))
不要使用他们！注意：这部分的内容其实是存在争议的！我收到过大量邮件说组合hash函数是有意义的。因为如果攻击者不知道我们用了哪个函数，就不可能事先计算出彩虹表，并且组合hash函数需要更多的计算时间。攻击者如果不知道hash算法的话自然是无法破解hash的。但是考虑到Kerckhoffs’s principle,攻击者通常都是能够接触到源码的(尤其是免费软件和开源软件)。通过一些目标系统的密码–hash对应关系来逆向出算法也不是非常困难。如果你想使用一个标准的”古怪”的hash函数，比如HMAC，是可以的。但是如果你的目的是想减慢hash的计算速度，那么可以读一下后面讨论的慢速hash函数部分。基于上面讨论的因素，最好的做法是使用标准的经过严格测试的hash算法。hash碰撞(Hash Collisions)因为hash函数是将任意数量的数据映射成一个固定长度的字符串，所以一定存在不同的输入经过hash之后变成相同的字符串的情况。加密hash函数(Cryptographic hash function)在设计的时候希望使这种碰撞攻击实现起来成本难以置信的高。但时不时的就有密码学家发现快速实现hash碰撞的方法。最近的一个例子就是MD5，它的碰撞攻击已经实现了。碰撞攻击是找到另外一个跟原密码不一样，但是具有相同hash的字符串。但是，即使在相对弱的hash算法，比如MD5,要实现碰撞攻击也需要大量的算力(computing power),所以在实际使用中偶然出现hash碰撞的情况几乎不太可能。一个使用加盐MD5的密码hash在实际使用中跟使用其他算法比如SHA256一样安全。不过如果可以的话，使用更安全的hash函数，比如SHA256, SHA512, RipeMD, WHIRLPOOL等是更好的选择。正确的方式：如何恰当的进行hash这部分会详细讨论如何恰当的进行密码hash。第一个章节是最基础的，这章节的内容是必须的。后面一个章节是阐述如何继续增强安全性，让hash破解变得异常困难。基础：使用加盐hash我们已经知道恶意黑客可以通过查表和彩虹表的方式快速的获得hash对应的明文密码，我们也知道了通过使用随机的盐可以解决这个问题。但是我们怎么生成盐，怎么在hash的过程中使用盐呢？盐要使用密码学上可靠安全的伪随机数生成器(Cryptographically Secure Pseudo-Random Number Generator (CSPRNG))来产生。CSPRNG跟普通的伪随机数生成器比如C语言中的rand(),有很大不同。正如它的名字说明的那样，CSPRNG提供一个高标准的随机数，是完全无法预测的。我们不希望我们的盐能够被预测到，所以一定要使用CSPRNG。下表提供了一些常用语言中的CSPRNG。
每一个用户，每一个密码都要使用不同的盐。用户每次创建账户或者修改密码都要使用一个新的随机盐。永远不要重复使用盐。盐的长度要足够，一个经验规则就是盐的至少要跟hash函数输出的长度一致。盐应该跟hash一起存储在用户信息表里。存储一个密码：
使用CSPRNG生成一个长的随机盐。
将密码和盐拼接在一起，使用标准的加密hash函数比如SHA256进行hash。
将盐和hash记录在用户数据库中。
验证一个密码：
从数据库中取出用户的盐和hash
将用户输入的密码和盐按相同方式拼接在一起，使用相同的hash函数进行hash
比较计算出的hash跟存储的hash是否相同。如果相同则密码正确。反之则密码错误。
客户端密码hash并不是HTTPS(SSL/TLS)的替代品。如果浏览器和服务器之间的连接是不安全的，中间人(man-in-the-middle)可能通过修改网页的加载的javascript移除掉hash函数来得到用户的明文密码。
有些浏览器可能不支持javascript，有些用户也会禁用javascript。为了更好的兼容性，需要检测用户的浏览器是否支持javascript，如果不支持的话就需要在服务端模拟客户端hash的逻辑。
客户端的hash也需要加盐。一个很容想到的方式就是使用客户端脚本请求服务器或得用户的盐。记住，不要使用这种方式。因为这样恶意攻击者就可以通过这个逻辑来判断一个用户名是否有效。因为我们已经在服务端进行了恰当的加盐的hash。所以这里使用用户名跟特定的字符串(比如域名)拼接作为客户端的盐是可以的。
使用慢速hash函数让破解更加困难:加盐可以让攻击者无法使用查表和彩虹表的方式对大量hash进行破解。但是依然无法避免对单个hash的字典和暴力攻击。高端的显卡(GPUs)和一些定制的硬件每秒可以计算数十亿的hash，所以针对单个hash的攻击依然有效。为了避免字典和暴力攻击，我们可以采用一种称为key扩展(key stretching)的技术。思路就是让hash的过程便得非常缓慢，即使使用高速GPU和特定的硬件，字典和暴力破解的速度也慢到没有实用价值。通过减慢hash的过程来防御攻击，但是hash速度依然可以保证用户使用的时候没有明显的延迟。key扩展的实现是使用一种大量消耗cpu资源的hash函数。不要去使用自己创造的迭代hash函数，那是不够的。要使用标准算法的hash函数，比如PBKDF2或者bcrypt。PHP实现可以在这里找到。这些算法采用了一个安全变量或者迭代次数作为参数。这个值决定了hash的过程具体有多慢。对于桌面软件和手机APP，确定这个参数的最好方式是在设备上运行一个标准测试程序得到hash时间大概在半秒左右的值。这样就可以避免暴力攻击，也不会影响用户体验。如果是在web应用中使用key扩展hash函数，需要考虑可能有大量的计算资源用来处理用户认证请求。攻击者可能通过这种方式来进行拒绝服务攻击。不过我依然推荐使用key扩展hash函数，只是迭代次数设置的小一点。这个次数需要根据自己服务器的计算能力和预计每秒需要处理的认证请求次数来设置。对于拒绝服务攻击可以通过让用户登陆的时候输入验证码的方式来防御。系统设计的时候一定要考虑到这个迭代次数将来可以方便的增加或降低。如果你担心计算机的能力不够强，而又希望在自己的web应用中使用key扩展hash函数，可以考虑在用户的浏览器运行hash函数。Stanford JavaScript Crypto Library包含了PBKDF2算法。在浏览器中进行hash需要考虑上面提到的几个方面。理论上不可能破解的hash：使用加密的key和密码hash硬件只要攻击者能够验证一个猜测的密码是正确还是错误，他们都可以使用字典或者暴力攻击破解hash。更深度的防御方法是加入一个保密的key(secret key)进行hash，这样只有知道这个key的人才能验证密码是否正确。这个可以通过两种方式来实现。一种是hash通过加密算法加密比如AES，或者使用基于key的hash函数(HMAC)。这个实现起来并不容易。key一定要做到保密，即使系统被攻破也不能泄露才行。但是如果攻击者获取了系统权限，无论key保存在哪里，都可能被获取到。所以这个key一定要保存在一个外部系统中，比如专门用来进行密码验证的物理隔离的服务器。或是使用安装在服务器上特殊硬件，比如YubiHSM。强烈建议所有大型的服务(超过10万用户)的公司使用这种方式。对于超过100万用户的服务商一定得采用这种方式保护用户信息。如果条件不允许使用专用验证的服务器和特殊的硬件，依然从这种方式中受益。大部分数据库泄露都是利用了SQL注入技术。sql注入大部分情况下，攻击者都没法读取服务器上的任意文件(关闭数据库服务器的文件权限)。如果你生成了一个随机的key，把它保存在了一个文件里。并且密码使用了加密key的加盐hash，单单sql注入攻击导致的hash泄露并不会影响用户的密码。虽然这种方式不如使用独立的系统来保存key安全，因为如果系统存在文件包含漏洞的话，攻击者就可能读取这个秘密文件了。不过，使用了加密key总归好过没有使用吧。需要注意使用key的hash并不是不需要加盐，聪明的攻击者总是会找到办法获取到key的。所以让hash在盐和key扩展的保护下非常重要。其他的安全措施密码hash仅仅是在发生安全事故的时候保护密码。它并不能让应用程序更加安全。对于保护用户密码hash更多的是需要保护密码hash不被偷走。即使经验丰富的程序也需要经过安全培训才能写出安全的应用。一个不错的学习web应用漏洞的资源是OWASP。除非你理解了OWASP Top Ten Vulnerability List,否则不要去写关系到敏感数据的程序。公司有责任确保所有的开发者都经过了足够的安全开发的培训。通过第三方的渗透测试也是不错的方式。即使最好的程序员也会犯错，所以让安全专家来审计代码总是有意义的。寻找一个可信赖的第三方或者自己招聘一个安全人员来机型定期的代码审计。安全评审要在应用生命周期的早期就开始并且贯穿整个开发过程。对网站进行入侵监控也十分重要。我建议至少招聘一名全职的安全人员进行入侵检测和安全事件响应。如果入侵没有检测到，攻击者可能让在你的网站上挂马影响你的用户。所以迅速的入侵检测和响应也很重要。经常提问的问题我应该使用什么hash算法可以使用
OpenWall的Portable PHP password hashing framework
经过充分测试的加密hash函数，比如SHA256, SHA512, RipeMD, WHIRLPOOL, SHA3等
设计良好的key扩展hash算法，比如PBKDF2，bcrypt，scrypt
crypt#Library_Function_crypt.283.29)的安全版本。($2y$, $5$, $6$)
不要使用
过时的hash函数，比如MD5,SHA1
crypt的不安全版本。($1$, $2$, $2x$, $3$)
任何自己设计的算法。
private static boolean slowEquals(byte[] a, byte[] b) { int diff = a.length ^ b.length; for(int i = 0; i< a.length && i< b.length; i++) diff |= a[i] ^ b[i]; return diff == 0; } private static boolean slowEquals(byte[] a, byte[] b){ int diff = a.length ^ b.length; for(int i = 0; i< a.length && i< b.length; i++) diff |= a[i] ^ b[i]; return diff == 0;}
这段代码使用了异或(XOR)操作符”^”来比较整数是否相等，而没有使用”==”操作符。原因在于如果两个数完全一致，异或之后的值为零。因为 0 XOR 0 = 0, 1 XOR 1 = 0, 0 XOR 1 = 1, 1 XOR 0 = 1。所以，第一行代码如果a.length等于b.length，变量diff等于0,否则的话diff就是一个非零的值。然后，让a，b的每一个字节XOR之后再跟diff OR。这样，只有diff一开始是0,并且，a，b的每一个字节XOR的结果也是零，最后循环完成后diff的值才是0,这种情况是a，b完全一样。否则最后diff是一个非零的值。我们使用XOR而不适用”==”的原因是”==”通常编译成分支的形式。比如C代码”diff &= a == b” 可能编译成下面的X86汇编。
MOV EAX, [A] CMP [B ], EAX JZ equal JMP done equal: AND [VALID], 1 done: AND [VALID], 0
分支会导致代码执行的时间出现差异。C代码的”diff |= a ^ b”编译之后类似于，
MOV EAX, [A] XOR EAX, [B ] OR [DIFF], EAX
执行时间跟两个变量是否相等没有关系。为什么要讨论这么多关于hash的东西用户在你的网站上输入密码，是相信你的安全性。如果你的数据库被黑了。而用户密码又没有恰当的保护，那么恶意的攻击者就可以利用这些密码尝试登陆其他的网站和服务。进行撞库攻击。(很多用户在所有的地方都是使用相同的密码)这不仅仅是你的网站安全，是你的所有用户的安全。你要对你用户的安全负责。PHP PBKDF2 密码hash代码
<?php /** Password Hashing With PBKDF2 (http://crackstation.net/hashing-security.htm).* Copyright (c) 2013, Taylor Hornby* All rights reserved.** Redistribution and use in source and binary forms, with or without* modification, are permitted provided that the following conditions are met:** 1. Redistributions of source code must retain the above copyright notice,* this list of conditions and the following disclaimer.** 2. Redistributions in binary form must reproduce the above copyright notice,* this list of conditions and the following disclaimer in the documentation* and/or other materials provided with the distribution.** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE* POSSIBILITY OF SUCH DAMAGE.*/ // These constants may be changed without breaking existing hashes. define("PBKDF2_HASH_ALGORITHM", "sha256"); define("PBKDF2_ITERATIONS", 1000); define("PBKDF2_SALT_BYTE_SIZE", 24); define("PBKDF2_HASH_BYTE_SIZE", 24); define("HASH_SECTIONS", 4); define("HASH_ALGORITHM_INDEX", 0); define("HASH_ITERATION_INDEX", 1); define("HASH_SALT_INDEX", 2); define("HASH_PBKDF2_INDEX", 3); function create_hash($password) { // format: algorithm:iterations:salt:hash $salt = base64_encode(mcrypt_create_iv(PBKDF2_SALT_BYTE_SIZE, MCRYPT_DEV_URANDOM)); return PBKDF2_HASH_ALGORITHM . ":" . PBKDF2_ITERATIONS . ":" . $salt . ":" . base64_encode(pbkdf2( PBKDF2_HASH_ALGORITHM, $password, $salt, PBKDF2_ITERATIONS, PBKDF2_HASH_BYTE_SIZE, true )); } function validate_password($password, $correct_hash) { $params = explode(":", $correct_hash); if(count($params)< HASH_SECTIONS) return false; $pbkdf2 = base64_decode($params[HASH_PBKDF2_INDEX]); return slow_equals( $pbkdf2, pbkdf2( $params[HASH_ALGORITHM_INDEX], $password, $params[HASH_SALT_INDEX], (int)$params[HASH_ITERATION_INDEX], strlen($pbkdf2), true ) ); } // Compares two strings $a and $b in length-constant time. function slow_equals($a, $b) { $diff = strlen($a) ^ strlen($b); for($i = 0; $i< strlen($a) && $i< strlen($b); $i++) { $diff |= ord($a[$i]) ^ ord($b[$i]); } return $diff === 0; } /** PBKDF2 key derivation function as defined by RSA's PKCS #5: https://www.ietf.org/rfc/rfc2898.txt* $algorithm - The hash algorithm to use. Recommended: SHA256* $password - The password.* $salt - A salt that is unique to the password.* $count - Iteration count. Higher is better, but slower. Recommended: At least 1000.* $key_length - The length of the derived key in bytes.* $raw_output - If true, the key is returned in raw binary format. Hex encoded otherwise.* Returns: A $key_length-byte key derived from the password and salt.** Test vectors can be found here: https://www.ietf.org/rfc/rfc6070.txt** This implementation of PBKDF2 was originally created by https://defuse.ca* With improvements by http://www.variations-of-shadow.com*/ function pbkdf2($algorithm, $password, $salt, $count, $key_length, $raw_output = false) { $algorithm = strtolower($algorithm); if(!in_array($algorithm, hash_algos(), true)) trigger_error('PBKDF2 ERROR: Invalid hash algorithm.', E_USER_ERROR); if($count<= 0 || $key_length<= 0) trigger_error('PBKDF2 ERROR: Invalid parameters.', E_USER_ERROR); if (function_exists("hash_pbkdf2")) { // The output length is in NIBBLES (4-bits) if $raw_output is false! if (!$raw_output) { $key_length = $key_length * 2; } return hash_pbkdf2($algorithm, $password, $salt, $count, $key_length, $raw_output); } $hash_length = strlen(hash($algorithm, "", true)); $block_count = ceil($key_length / $hash_length); $output = ""; for($i = 1; $i<= $block_count; $i++) { // $i encoded as 4 bytes, big endian. $last = $salt . pack("N", $i); // first iteration $last = $xorsum = hash_hmac($algorithm, $last, $password, true); // perform the other $count - 1 iterations for ($j = 1; $j< $count; $j++) { $xorsum ^= ($last = hash_hmac($algorithm, $last, $password, true)); } $output .= $xorsum; } if($raw_output) return substr($output, 0, $key_length); else return bin2hex(substr($output, 0, $key_length)); } ?><?php/** Password Hashing With PBKDF2 (http://crackstation.net/hashing-security.htm).* Copyright (c) 2013, Taylor Hornby* All rights reserved.** Redistribution and use in source and binary forms, with or without* modification, are permitted provided that the following conditions are met:** 1. Redistributions of source code must retain the above copyright notice,* this list of conditions and the following disclaimer.** 2. Redistributions in binary form must reproduce the above copyright notice,* this list of conditions and the following disclaimer in the documentation* and/or other materials provided with the distribution.** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE* POSSIBILITY OF SUCH DAMAGE.*/// These constants may be changed without breaking existing hashes.define("PBKDF2_HASH_ALGORITHM", "sha256");define("PBKDF2_ITERATIONS", 1000);define("PBKDF2_SALT_BYTE_SIZE", 24);define("PBKDF2_HASH_BYTE_SIZE", 24);define("HASH_SECTIONS", 4);define("HASH_ALGORITHM_INDEX", 0);define("HASH_ITERATION_INDEX", 1);define("HASH_SALT_INDEX", 2);define("HASH_PBKDF2_INDEX", 3);function create_hash($password){// format: algorithm:iterations:salt:hash$salt = base64_encode(mcrypt_create_iv(PBKDF2_SALT_BYTE_SIZE, MCRYPT_DEV_URANDOM));return PBKDF2_HASH_ALGORITHM . ":" . PBKDF2_ITERATIONS . ":" . $salt . ":" .base64_encode(pbkdf2(PBKDF2_HASH_ALGORITHM,$password,$salt,PBKDF2_ITERATIONS,PBKDF2_HASH_BYTE_SIZE,true));}function validate_password($password, $correct_hash){$params = explode(":", $correct_hash);if(count($params)< HASH_SECTIONS)return false;$pbkdf2 = base64_decode($params[HASH_PBKDF2_INDEX]);return slow_equals($pbkdf2,pbkdf2($params[HASH_ALGORITHM_INDEX],$password,$params[HASH_SALT_INDEX],(int)$params[HASH_ITERATION_INDEX],strlen($pbkdf2),true));}// Compares two strings $a and $b in length-constant time.function slow_equals($a, $b){$diff = strlen($a) ^ strlen($b);for($i = 0; $i< strlen($a) && $i< strlen($b); $i++){$diff |= ord($a[$i]) ^ ord($b[$i]);}return $diff === 0;}/** PBKDF2 key derivation function as defined by RSA's PKCS #5: https://www.ietf.org/rfc/rfc2898.txt* $algorithm - The hash algorithm to use. Recommended: SHA256* $password - The password.* $salt - A salt that is unique to the password.* $count - Iteration count. Higher is better, but slower. Recommended: At least 1000.* $key_length - The length of the derived key in bytes.* $raw_output - If true, the key is returned in raw binary format. Hex encoded otherwise.* Returns: A $key_length-byte key derived from the password and salt.** Test vectors can be found here: https://www.ietf.org/rfc/rfc6070.txt** This implementation of PBKDF2 was originally created by https://defuse.ca* With improvements by http://www.variations-of-shadow.com*/function pbkdf2($algorithm, $password, $salt, $count, $key_length, $raw_output = false){$algorithm = strtolower($algorithm);if(!in_array($algorithm, hash_algos(), true))trigger_error('PBKDF2 ERROR: Invalid hash algorithm.', E_USER_ERROR);if($count<= 0 || $key_length<= 0)trigger_error('PBKDF2 ERROR: Invalid parameters.', E_USER_ERROR);if (function_exists("hash_pbkdf2")) {// The output length is in NIBBLES (4-bits) if $raw_output is false!if (!$raw_output) {$key_length = $key_length * 2;}return hash_pbkdf2($algorithm, $password, $salt, $count, $key_length, $raw_output);}$hash_length = strlen(hash($algorithm, "", true));$block_count = ceil($key_length / $hash_length);$output = "";for($i = 1; $i<= $block_count; $i++) {// $i encoded as 4 bytes, big endian.$last = $salt . pack("N", $i);// first iteration$last = $xorsum = hash_hmac($algorithm, $last, $password, true);// perform the other $count - 1 iterationsfor ($j = 1; $j< $count; $j++) {$xorsum ^= ($last = hash_hmac($algorithm, $last, $password, true));}$output .= $xorsum;}if($raw_output)return substr($output, 0, $key_length);elsereturn bin2hex(substr($output, 0, $key_length));}?>
java PBKDF2 密码hash代码
/** Password Hashing With PBKDF2 (http://crackstation.net/hashing-security.htm).* Copyright (c) 2013, Taylor Hornby* All rights reserved.** Redistribution and use in source and binary forms, with or without* modification, are permitted provided that the following conditions are met:** 1. Redistributions of source code must retain the above copyright notice,* this list of conditions and the following disclaimer.** 2. Redistributions in binary form must reproduce the above copyright notice,* this list of conditions and the following disclaimer in the documentation* and/or other materials provided with the distribution.** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE* POSSIBILITY OF SUCH DAMAGE.*/ import java.security.SecureRandom; import javax.crypto.spec.PBEKeySpec; import javax.crypto.SecretKeyFactory; import java.math.BigInteger; import java.security.NoSuchAlgorithmException; import java.security.spec.InvalidKeySpecException; /** PBKDF2 salted password hashing.* Author: havoc AT defuse.ca* www: http://crackstation.net/hashing-security.htm*/ public class PasswordHash { public static final String PBKDF2_ALGORITHM = "PBKDF2WithHmacSHA1"; // The following constants may be changed without breaking existing hashes. public static final int SALT_BYTE_SIZE = 24; public static final int HASH_BYTE_SIZE = 24; public static final int PBKDF2_ITERATIONS = 1000; public static final int ITERATION_INDEX = 0; public static final int SALT_INDEX = 1; public static final int PBKDF2_INDEX = 2; /** * Returns a salted PBKDF2 hash of the password. * * @param password the password to hash * @return a salted PBKDF2 hash of the password */ public static String createHash(String password) throws NoSuchAlgorithmException, InvalidKeySpecException { return createHash(password.toCharArray()); } /** * Returns a salted PBKDF2 hash of the password. * * @param password the password to hash * @return a salted PBKDF2 hash of the password */ public static String createHash(char[] password) throws NoSuchAlgorithmException, InvalidKeySpecException { // Generate a random salt SecureRandom random = new SecureRandom(); byte[] salt = new byte[SALT_BYTE_SIZE]; random.nextBytes(salt); // Hash the password byte[] hash = pbkdf2(password, salt, PBKDF2_ITERATIONS, HASH_BYTE_SIZE); // format iterations:salt:hash return PBKDF2_ITERATIONS + ":" + toHex(salt) + ":" + toHex(hash); } /** * Validates a password using a hash. * * @param password the password to check * @param correctHash the hash of the valid password * @return true if the password is correct, false if not */ public static boolean validatePassword(String password, String correctHash) throws NoSuchAlgorithmException, InvalidKeySpecException { return validatePassword(password.toCharArray(), correctHash); } /** * Validates a password using a hash. * * @param password the password to check * @param correctHash the hash of the valid password * @return true if the password is correct, false if not */ public static boolean validatePassword(char[] password, String correctHash) throws NoSuchAlgorithmException, InvalidKeySpecException { // Decode the hash into its parameters String[] params = correctHash.split(":"); int iterations = Integer.parseInt(params[ITERATION_INDEX]); byte[] salt = fromHex(params[SALT_INDEX]); byte[] hash = fromHex(params[PBKDF2_INDEX]); // Compute the hash of the provided password, using the same salt, // iteration count, and hash length byte[] testHash = pbkdf2(password, salt, iterations, hash.length); // Compare the hashes in constant time. The password is correct if // both hashes match. return slowEquals(hash, testHash); } /** * Compares two byte arrays in length-constant time. This comparison method * is used so that password hashes cannot be extracted from an on-line * system using a timing attack and then attacked off-line. * * @param a the first byte array * @param b the second byte array * @return true if both byte arrays are the same, false if not */ private static boolean slowEquals(byte[] a, byte[] b) { int diff = a.length ^ b.length; for(int i = 0; i< a.length && i< b.length; i++) diff |= a[i] ^ b[i]; return diff == 0; } /** * Computes the PBKDF2 hash of a password. * * @param password the password to hash. * @param salt the salt * @param iterations the iteration count (slowness factor) * @param bytes the length of the hash to compute in bytes * @return the PBDKF2 hash of the password */ private static byte[] pbkdf2(char[] password, byte[] salt, int iterations, int bytes) throws NoSuchAlgorithmException, InvalidKeySpecException { PBEKeySpec spec = new PBEKeySpec(password, salt, iterations, bytes * 8); SecretKeyFactory skf = SecretKeyFactory.getInstance(PBKDF2_ALGORITHM); return skf.generateSecret(spec).getEncoded(); } /** * Converts a string of hexadecimal characters into a byte array. * * @param hex the hex string * @return the hex string decoded into a byte array */ private static byte[] fromHex(String hex) { byte[] binary = new byte[hex.length() / 2]; for(int i = 0; i< binary.length; i++) { binary[i] = (byte)Integer.parseInt(hex.substring(2*i, 2*i+2), 16); } return binary; } /** * Converts a byte array into a hexadecimal string. * * @param array the byte array to convert * @return a length*2 character string encoding the byte array */ private static String toHex(byte[] array) { BigInteger bi = new BigInteger(1, array); String hex = bi.toString(16); int paddingLength = (array.length * 2) - hex.length(); if(paddingLength >0) return String.format("%0" + paddingLength + "d", 0) + hex; else return hex; } /** * Tests the basic functionality of the PasswordHash class * * @param args ignored */ public static void main(String[] args) { try { // Print out 10 hashes for(int i = 0; i< 10; i++) System.out.println(PasswordHash.createHash("p\r\nassw0Rd!")); // Test password validation boolean failure = false; System.out.println("Running tests..."); for(int i = 0; i< 100; i++) { String password = ""+i; String hash = createHash(password); String secondHash = createHash(password); if(hash.equals(secondHash)) { System.out.println("FAILURE: TWO HASHES ARE EQUAL!"); failure = true; } String wrongPassword = ""+(i+1); if(validatePassword(wrongPassword, hash)) { System.out.println("FAILURE: WRONG PASSWORD ACCEPTED!"); failure = true; } if(!validatePassword(password, hash)) { System.out.println("FAILURE: GOOD PASSWORD NOT ACCEPTED!"); failure = true; } } if(failure) System.out.println("TESTS FAILED!"); else System.out.println("TESTS PASSED!"); } catch(Exception ex) { System.out.println("ERROR: " + ex); } } } /* * Password Hashing With PBKDF2 (http://crackstation.net/hashing-security.htm). * Copyright (c) 2013, Taylor Hornby * All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions are met: * * 1. Redistributions of source code must retain the above copyright notice, * this list of conditions and the following disclaimer. * * 2. Redistributions in binary form must reproduce the above copyright notice, * this list of conditions and the following disclaimer in the documentation * and/or other materials provided with the distribution. * * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE * POSSIBILITY OF SUCH DAMAGE. */ import java.security.SecureRandom;import javax.crypto.spec.PBEKeySpec;import javax.crypto.SecretKeyFactory;import java.math.BigInteger;import java.security.NoSuchAlgorithmException;import java.security.spec.InvalidKeySpecException; /* * PBKDF2 salted password hashing. * Author: havoc AT defuse.ca * www: http://crackstation.net/hashing-security.htm */public class PasswordHash{ public static final String PBKDF2_ALGORITHM = "PBKDF2WithHmacSHA1"; // The following constants may be changed without breaking existing hashes. public static final int SALT_BYTE_SIZE = 24; public static final int HASH_BYTE_SIZE = 24; public static final int PBKDF2_ITERATIONS = 1000; public static final int ITERATION_INDEX = 0; public static final int SALT_INDEX = 1; public static final int PBKDF2_INDEX = 2; /** * Returns a salted PBKDF2 hash of the password. * * @param password the password to hash * @return a salted PBKDF2 hash of the password */ public static String createHash(String password) throws NoSuchAlgorithmException, InvalidKeySpecException { return createHash(password.toCharArray()); } /** * Returns a salted PBKDF2 hash of the password. * * @param password the password to hash * @return a salted PBKDF2 hash of the password */ public static String createHash(char[] password) throws NoSuchAlgorithmException, InvalidKeySpecException { // Generate a random salt SecureRandom random = new SecureRandom(); byte[] salt = new byte[SALT_BYTE_SIZE]; random.nextBytes(salt); // Hash the password byte[] hash = pbkdf2(password, salt, PBKDF2_ITERATIONS, HASH_BYTE_SIZE); // format iterations:salt:hash return PBKDF2_ITERATIONS + ":" + toHex(salt) + ":" + toHex(hash); } /** * Validates a password using a hash. * * @param password the password to check * @param correctHash the hash of the valid password * @return true if the password is correct, false if not */ public static boolean validatePassword(String password, String correctHash) throws NoSuchAlgorithmException, InvalidKeySpecException { return validatePassword(password.toCharArray(), correctHash); } /** * Validates a password using a hash. * * @param password the password to check * @param correctHash the hash of the valid password * @return true if the password is correct, false if not */ public static boolean validatePassword(char[] password, String correctHash) throws NoSuchAlgorithmException, InvalidKeySpecException { // Decode the hash into its parameters String[] params = correctHash.split(":"); int iterations = Integer.parseInt(params[ITERATION_INDEX]); byte[] salt = fromHex(params[SALT_INDEX]); byte[] hash = fromHex(params[PBKDF2_INDEX]); // Compute the hash of the provided password, using the same salt, // iteration count, and hash length byte[] testHash = pbkdf2(password, salt, iterations, hash.length); // Compare the hashes in constant time. The password is correct if // both hashes match. return slowEquals(hash, testHash); } /** * Compares two byte arrays in length-constant time. This comparison method * is used so that password hashes cannot be extracted from an on-line * system using a timing attack and then attacked off-line. * * @param a the first byte array * @param b the second byte array * @return true if both byte arrays are the same, false if not */ private static boolean slowEquals(byte[] a, byte[] b) { int diff = a.length ^ b.length; for(int i = 0; i< a.length && i< b.length; i++) diff |= a[i] ^ b[i]; return diff == 0; } /** * Computes the PBKDF2 hash of a password. * * @param password the password to hash. * @param salt the salt * @param iterations the iteration count (slowness factor) * @param bytes the length of the hash to compute in bytes * @return the PBDKF2 hash of the password */ private static byte[] pbkdf2(char[] password, byte[] salt, int iterations, int bytes) throws NoSuchAlgorithmException, InvalidKeySpecException { PBEKeySpec spec = new PBEKeySpec(password, salt, iterations, bytes * 8); SecretKeyFactory skf = SecretKeyFactory.getInstance(PBKDF2_ALGORITHM); return skf.generateSecret(spec).getEncoded(); } /** * Converts a string of hexadecimal characters into a byte array. * * @param hex the hex string * @return the hex string decoded into a byte array */ private static byte[] fromHex(String hex) { byte[] binary = new byte[hex.length() / 2]; for(int i = 0; i< binary.length; i++) { binary[i] = (byte)Integer.parseInt(hex.substring(2*i, 2*i+2), 16); } return binary; } /** * Converts a byte array into a hexadecimal string. * * @param array the byte array to convert * @return a length*2 character string encoding the byte array */ private static String toHex(byte[] array) { BigInteger bi = new BigInteger(1, array); String hex = bi.toString(16); int paddingLength = (array.length * 2) - hex.length(); if(paddingLength >0) return String.format("%0" + paddingLength + "d", 0) + hex; else return hex; } /** * Tests the basic functionality of the PasswordHash class * * @param args ignored */ public static void main(String[] args) { try { // Print out 10 hashes for(int i = 0; i< 10; i++) System.out.println(PasswordHash.createHash("p\r\nassw0Rd!")); // Test password validation boolean failure = false; System.out.println("Running tests..."); for(int i = 0; i< 100; i++) { String password = ""+i; String hash = createHash(password); String secondHash = createHash(password); if(hash.equals(secondHash)) { System.out.println("FAILURE: TWO HASHES ARE EQUAL!"); failure = true; } String wrongPassword = ""+(i+1); if(validatePassword(wrongPassword, hash)) { System.out.println("FAILURE: WRONG PASSWORD ACCEPTED!"); failure = true; } if(!validatePassword(password, hash)) { System.out.println("FAILURE: GOOD PASSWORD NOT ACCEPTED!"); failure = true; } } if(failure) System.out.println("TESTS FAILED!"); else System.out.println("TESTS PASSED!"); } catch(Exception ex) { System.out.println("ERROR: " + ex); } } }
ASP.NET (C#)密码hash代码
/* * Password Hashing With PBKDF2 (http://crackstation.net/hashing-security.htm). * Copyright (c) 2013, Taylor Hornby * All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions are met: * * 1. Redistributions of source code must retain the above copyright notice, * this list of conditions and the following disclaimer. * * 2. Redistributions in binary form must reproduce the above copyright notice, * this list of conditions and the following disclaimer in the documentation * and/or other materials provided with the distribution. * * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE * POSSIBILITY OF SUCH DAMAGE. */ using System; using System.Text; using System.Security.Cryptography; namespace PasswordHash { ///
Ruby (on Rails) 密码hash代码
# Password Hashing With PBKDF2 (http://crackstation.net/hashing-security.htm). # Copyright (c) 2013, Taylor Hornby # All rights reserved. # # Redistribution and use in source and binary forms, with or without # modification, are permitted provided that the following conditions are met: # # 1. Redistributions of source code must retain the above copyright notice, # this list of conditions and the following disclaimer. # # 2. Redistributions in binary form must reproduce the above copyright notice, # this list of conditions and the following disclaimer in the documentation # and/or other materials provided with the distribution. # # THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" # AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE # IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE # ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE # LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR # CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF # SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS # INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN # CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) # ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE # POSSIBILITY OF SUCH DAMAGE. require 'securerandom' require 'openssl' require 'base64' # Salted password hashing with PBKDF2-SHA1. # Authors: @RedragonX (dicesoft.net), havoc AT defuse.ca # www: http://crackstation.net/hashing-security.htm module PasswordHash # The following constants can be changed without breaking existing hashes. PBKDF2_ITERATIONS = 1000 SALT_BYTE_SIZE = 24 HASH_BYTE_SIZE = 24 HASH_SECTIONS = 4 SECTION_DELIMITER = ':' ITERATIONS_INDEX = 1 SALT_INDEX = 2 HASH_INDEX = 3 # Returns a salted PBKDF2 hash of the password. def self.createHash( password ) salt = SecureRandom.base64( SALT_BYTE_SIZE ) pbkdf2 = OpenSSL::PKCS5::pbkdf2_hmac_sha1( password, salt, PBKDF2_ITERATIONS, HASH_BYTE_SIZE ) return ["sha1", PBKDF2_ITERATIONS, salt, Base64.encode64( pbkdf2 )].join( SECTION_DELIMITER ) end # Checks if a password is correct given a hash of the correct one. # correctHash must be a hash string generated with createHash. def self.validatePassword( password, correctHash ) params = correctHash.split( SECTION_DELIMITER ) return false if params.length != HASH_SECTIONS pbkdf2 = Base64.decode64( params[HASH_INDEX] ) testHash = OpenSSL::PKCS5::pbkdf2_hmac_sha1( password, params[SALT_INDEX], params[ITERATIONS_INDEX].to_i, pbkdf2.length ) return pbkdf2 == testHash end # Run tests to ensure the module is functioning properly. # Returns true if all tests succeed, false if not. def self.runSelfTests puts "Sample hashes:" 3.times { puts createHash("password") } puts "\nRunning self tests..." @@allPass = true correctPassword = 'aaaaaaaaaa' wrongPassword = 'aaaaaaaaab' hash = createHash(correctPassword) assert( validatePassword( correctPassword, hash ) == true, "correct password" ) assert( validatePassword( wrongPassword, hash ) == false, "wrong password" ) h1 = hash.split( SECTION_DELIMITER ) h2 = createHash( correctPassword ).split( SECTION_DELIMITER ) assert( h1[HASH_INDEX] != h2[HASH_INDEX], "different hashes" ) assert( h1[SALT_INDEX] != h2[SALT_INDEX], "different salt" ) if @@allPass puts "*** ALL TESTS PASS ***" else puts "*** FAILURES ***" end return @@allPass end def self.assert( truth, msg ) if truth puts "PASS [#{msg}]" else puts "FAIL [#{msg}]" @@allPass = false end end end PasswordHash.runSelfTests # Password Hashing With PBKDF2 (http://crackstation.net/hashing-security.htm).# Copyright (c) 2013, Taylor Hornby# All rights reserved.# # Redistribution and use in source and binary forms, with or without # modification, are permitted provided that the following conditions are met:# # 1. Redistributions of source code must retain the above copyright notice, # this list of conditions and the following disclaimer.# # 2. Redistributions in binary form must reproduce the above copyright notice,# this list of conditions and the following disclaimer in the documentation # and/or other materials provided with the distribution.# # THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" # AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE # IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE # ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE # LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR # CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF # SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS # INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN # CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) # ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE # POSSIBILITY OF SUCH DAMAGE.require 'securerandom'require 'openssl'require 'base64'# Salted password hashing with PBKDF2-SHA1.# Authors: @RedragonX (dicesoft.net), havoc AT defuse.ca # www: http://crackstation.net/hashing-security.htmmodule PasswordHash # The following constants can be changed without breaking existing hashes. PBKDF2_ITERATIONS = 1000 SALT_BYTE_SIZE = 24 HASH_BYTE_SIZE = 24 HASH_SECTIONS = 4 SECTION_DELIMITER = ':' ITERATIONS_INDEX = 1 SALT_INDEX = 2 HASH_INDEX = 3 # Returns a salted PBKDF2 hash of the password. def self.createHash( password ) salt = SecureRandom.base64( SALT_BYTE_SIZE ) pbkdf2 = OpenSSL::PKCS5::pbkdf2_hmac_sha1( password, salt, PBKDF2_ITERATIONS, HASH_BYTE_SIZE ) return ["sha1", PBKDF2_ITERATIONS, salt, Base64.encode64( pbkdf2 )].join( SECTION_DELIMITER ) end # Checks if a password is correct given a hash of the correct one. # correctHash must be a hash string generated with createHash. def self.validatePassword( password, correctHash ) params = correctHash.split( SECTION_DELIMITER ) return false if params.length != HASH_SECTIONS pbkdf2 = Base64.decode64( params[HASH_INDEX] ) testHash = OpenSSL::PKCS5::pbkdf2_hmac_sha1( password, params[SALT_INDEX], params[ITERATIONS_INDEX].to_i, pbkdf2.length ) return pbkdf2 == testHash end # Run tests to ensure the module is functioning properly. # Returns true if all tests succeed, false if not. def self.runSelfTests puts "Sample hashes:" 3.times { puts createHash("password") } puts "\nRunning self tests..." @@allPass = true correctPassword = 'aaaaaaaaaa' wrongPassword = 'aaaaaaaaab' hash = createHash(correctPassword) assert( validatePassword( correctPassword, hash ) == true, "correct password" ) assert( validatePassword( wrongPassword, hash ) == false, "wrong password" ) h1 = hash.split( SECTION_DELIMITER ) h2 = createHash( correctPassword ).split( SECTION_DELIMITER ) assert( h1[HASH_INDEX] != h2[HASH_INDEX], "different hashes" ) assert( h1[SALT_INDEX] != h2[SALT_INDEX], "different salt" ) if @@allPass puts "*** ALL TESTS PASS ***" else puts "*** FAILURES ***" end return @@allPass end def self.assert( truth, msg ) if truth puts "PASS [#{msg}]" else puts "FAIL [#{msg}]" @@allPass = false end end end PasswordHash.runSelfTests
用户评论
这篇文章讲得很棒！终于有人提到了盐值和哈希函数的重要性，太重要了！我之前还对这些概念一头雾水，现在明白了以后，感觉学习起来更有目标了
有8位网友表示赞同！
文章说的没错，安全的存储用户密码确实很重要。特别是现在网络安全隐患越来越大，需要我们更加重视用户的隐私信息保护。
有17位网友表示赞同！
我是做前端开发的，我觉得这篇文章对我还有一些帮助。我之前处理过密码的场景，但没有那么全面的了解安全性问题，以后我会认真学习一下这些方法
有16位网友表示赞同！
虽然文章说得正确，但对于技术不太了解的用户来说，可能有点难懂吧？能不能换个更容易理解的方式描述那些复杂的安全机制？
有6位网友表示赞同！
这种存储方式好像听过啊，以前在公司培训的时候也聊过，当时感觉很枯燥，现在仔细想起来，确实挺重要的。不过我还有个疑问，加密后的密码还是会被攻击者破解吗？
有11位网友表示赞同！
我觉得这篇文章还是很有价值的，特别是对于那些想自己搭建网站或者应用的人来说，掌握这些安全知识非常重要，可以有效避免数据泄露的风险。
有15位网友表示赞同！
文章里提到使用多因子验证，我想说这确实是个很不错的安全方案！我的银行账户和邮箱都使用了多因子验证，感觉安全性提升了不少。
有16位网友表示赞同！
说的对，用户自己也要注意保护自己的账号和密码，不要随意泄露信息，也不要重复使用同一个密码在不同平台上。
有5位网友表示赞同！
我只想说一句: 永远不要将用户的密码存储为明文！这真是太危险了！真的希望更多开发者都能重视安全问题，做好数据保护工作。
有20位网友表示赞同！
哈希函数和盐值这两个概念听起来很复杂，我不是技术专业的，有点难以理解。能不能用一些通俗的例子解释一下？
有17位网友表示赞同！
感觉这篇文章讲得很有道理，但我觉得对于网站或者应用开发者来说，安全知识是必须掌握的基本技能，应该在学习开发过程中就强调这个重要性。
有16位网友表示赞同！
我个人觉得使用云端存储密码这种方式相对比较安全的，因为云服务商通常会 invests 大量资源在安全保障方面。当然，用户也需要自己做好密码管理工作，选择信誉度高的云服务商，并定期更换密码是必要的。
有6位网友表示赞同！
这篇文章让我意识到数据安全的重要性，现在有很多软件或者网站都会收集用户的个人信息，我们需要谨慎对待这些信息的存储和使用，保护自己的隐私权.
有20位网友表示赞同！
我之前就有过一次因为泄露用户密码被攻击的经历，真是让人心痛。希望更多开发者能够重视安全的存储密码这件事，避免更多用户遭受损失。
有13位网友表示赞同！
如果只是为了满足安全性的需求，那么选择云端存储密码是一个不错的方案. 但是对于一些需要高度安全性的数据来说，还需要考虑其他因素，例如是否要对存储的数据进行脱敏处理。
有10位网友表示赞同！
这篇文章讲得不错，但我个人觉得最重要的一点是培养用户自身的安全意识，不要轻易泄露自己的密码信息，并且要有定期更换密码的习惯
有17位网友表示赞同！
对于普通用户来说，掌握一些基本的网络安全知识已经足够了，比如使用强密码、不要点击可疑链接等等，不必过于担心复杂的网络安全技术，因为那些技术主要是针对专业人员使用的。
有20位网友表示赞同！
我觉得这篇文章对我们每个人都有很重要的意义，无论你是开发者、网站运营商还是普通用户，都需要重视用户的密码安全，做好数据保护工作才能有效防止信息泄露和攻击。
有18位网友表示赞同！