md5 | 易学教程

Generating one MD5/SHA1 checksum of multiple files in Python

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问题 I have looked through several topics about calculating checksums of files in Python but none of them answered the question about one sum from multiple files. I have several files in sub directories and would like to determine if there was any change in one or more of them. Is there a way to generate one sum from multiple files? EDIT: This is the way I do it to get a list of sums: checksums = [(fname, hashlib.md5(open(fname, 'rb').read()).digest()) for fname in flist] 回答1: So I made it :) This

How to include Content-MD5 header in FineUploader Azure request?

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问题 I would like to use the Content-MD5 header to supply Azure with a client-side generated MD5 hash of the files being uploaded. How would I accomplish this task in FineUploader? Target audience: Firefox, Chrome, Safari, Opera and IE10+. Judging by this answer I gather that it should be possible but at least half of our clients will run on very old (slow) computers. Is it feasible to do this client side MD5 hashing approach then? Somewhat related side question: I was also thinking that it might

Most efficient way to change the hash type of a password (md5 to sha1)

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问题 I have a system using MD5 to hash passwords from my users and store it into my database. Now, I'm changing to another system that uses SHA1 (and a unique system SALT, not user-unique) to hash the passwords. How do I manage to get the user old MD5 password turned into my new SHA1 password with PHP? 回答1: You can not convert md5 to sha but really your users only use password when they are about to login so you can modify your script a little to do the update automatically // The user is not

How does comparing images through md5 work?

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问题 Does this method compare the pixel values of the images? I'm guessing it won't work because they are different sizes from each other but what if they are identical, but in different formats? For example, I took a screenshot and saved as a .jpg and another and saved as a .gif . 回答1: An MD5 hash is of the actual binary data, so different formats will have completely different binary data. so for MD5 hashes to match, they must be identical files. (There are exceptions in fringe cases.) This is

Should security question answers be hashed?

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问题 I'm working to a security system for a web application - admin section. If one admin want to make some important changes in application he will need to a answer to a security question. My question is: the answer to this question should be hashed in database? Also, I'm thinking to give to the administrators posibility to change their question/answer but admin could do this just if he confirm his identity using password. Is this a good approach? 回答1: Hashing it is a great idea, in my opinion.

微博URL短网址生成算法原理及（java版、php版实现实例）

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短网址（Short URL），顾名思义就是在形式上比较短的网址。通常用的是asp或者php转向，在Web 2.0的今天，不得不说，这是一个潮流。目前已经有许多类似服务，借助短网址您可以用简短的网址替代原来冗长的网址，让使用者可以更容易的分享链接。例如： http://t.cn/SzjPjA 短网址服务，可能很多朋友都已经不再陌生，现在大部分微博、手机邮件提醒等地方已经有很多应用模式了，并占据了一定的市场。估计很多朋友现在也正在使用。看过新浪的短连接服务，发现后面主要有6个字符串组成，于是第一个想到的就是原来公司写的一个游戏激活码规则，也就是下面的算法2， 26个大写字母 26小写字母，10个数字，随机生成6个然后插入数据库对应一个id，短连接跳转的时候，根据字符串查询到对应id，即可实现相应的跳转！不过2的62次方，不知道有没有重复的，小概率可以，但是对应不是很大的网站应该足够了自从twitter推出短网址(shorturl),继之国内各大微博跟风,google公开goo.gl使用API,短网址之风愈演愈烈.不得不说这是一个新兴又一大热门web2.0服务.现整理一下,包括完整短网址网站,短网址生成原理,算法举例,以及优劣比较,同时还介绍几个phper个人实现的。短链接的好处： 1、内容需要；2、用户友好；3、便于管理。为什么要这样做的，原因我想有这样几点：

Calculate MD5 of a string in C++

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问题 I have a nice example of memory mapped files that calculates the MD5 hash of a file. That works fine with no problems. I would like to change it to calculate the MD5 hash of a string. So the example is: (include #include <openssl/md5.h> to run this code, and also boost stuff if you want to run the one with the file) unsigned char result[MD5_DIGEST_LENGTH]; boost::iostreams::mapped_file_source src(path); MD5((unsigned char*)src.data(), src.size(), result); std::ostringstream sout; sout<<std:

MD5 using Groovy in SoapUI

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问题 I created a test case which contains parameters that consist of key and value. I need to take all those parameters in an alphabetic order, and then create a MD5 hash value which i will pass to one of the parameters of this test. Any suggestions? i looked in google and cannot find anything helpful. Thanks ahead! 回答1: You can retrieve the SoapUI's test case properties using a Groovy Script test step as given below. def map = context.testCase.properties.keySet().inject([:]){map, key -> map[key]

Hash algorithm with alphanumeric output of 20 characters max

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问题 I need an hash algorithm that outputs an alphanumeric string that is max 20 characters long. For "alphanumeric" I mean [a-zA-Z0-9] . Inputs are UUIDs in canonical form (example 550e8400-e29b-41d4-a716-446655440000 ) In alternative is there a way to convert a SHA1 or MD5 hash to a string with these limitations? Thanks. EDIT Doesn't need to be cryptographically secure. Collisions make data inaccurate, but if they happen sporadically I can live with it. EDIT 2 I don't know if truncating MD5 or

Calculating MD5 of string from Microsoft Access

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问题 How do I calculate an MD5 of a string client side in Microsoft Access? 回答1: If you are implementing MD5 through a VBA module then there are several options. I haven't tried this, but a quick search for "md5 vba" returned this basMD5.bas file. It is not one of the common open source licenses though. From the "MD5 Homepage (unofficial)" in the Visual Basic section: Francisco Carlos Piragibe de Almeida has created a DLL with a BAS wrapper module for use in VB projects (19K download) and an