md5 | 易学教程

How to easily apply Crypto++ hash functions?

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问题 Can someone help me how can I easily use hash functions from Crypto++ library? I tried used these codes for SHA1 and MD5. I have many errors on line where is StringSink . The errors are like: undefined reference to `CryptoPP::StringSinkTemplate::StringSinkTemplate(std::string&)' Thanks for help. // SHA CryptoPP::SHA1 sha1; std::string source = "Hello"; std::string hash = ""; CryptoPP::StringSource(source, true, new CryptoPP::HashFilter(sha1, new CryptoPP::HexEncoder(new CryptoPP::StringSink

How to XOR md5 hash values and cast them to HEX in postgresql

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问题 What I have tried so far SELECT md5(text) will return text (hex strings) . After that We need to xor them SELECT x'hex_string' # x'hex_string'; But the above results in binary values. How do I again convert them into hex string? Is there anyway to xor md5 values in postgresql and convert this into hexadecimal values again ? 回答1: Those binary values are in fact of type bit varying , which differs significantly from bytea . bit varying comes with built-in support for XOR and such, but

Memcache key generation strategy

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问题 Given function f1 which receives n String arguments, what would be considered better ,in terms of runtime performance, random key generation strategy for memcache? Our Memcache client does internal md5sum hashing on the keys it gets: public class MemcacheClient { public Object get(String key) { String md5 = Md5sum.md5(key) // Talk to memcached to get the Serialization... return memcached(md5); } } My usage scenarios are: First option public static String f1(String s1, String s2, String s3,

Password Recovery: How to decrypt an md5 encrypted password? [duplicate]

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问题 This question already has answers here : Closed 6 years ago . Possible Duplicate: Is it possible to decrypt md5 hashes? In my website, I'm using md5 encryption for the password. So it's saving in the encrypted form in the database. For doing the password recovery, how can I decrypt the encrypted password ?? Please Help :) 回答1: As others described quite well, you cannot easily 'decrypt' an MD5 hash. I guess the best way to do your password recovery is like this: A user can request password

Is the md5sum linux command working right?

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问题 According to Wikipedia, the md5 sum of an empty string is d41d8cd98f00b204e9800998ecf8427e I confirmed this with my md5 library However, when I run echo "" | md5sum in my linux shell, I get 68b329da9893e34099c7d8ad5cb9c940 - In fact, none of my hashes match the output of the md5sum command. Any thoughts on this discrepancy? 回答1: With that command, you are calculating the md5sum of a single newline character. Try instead: echo -n "" | md5sum 回答2: You must eliminate the new line that echo

MD5 hash of a file using javascript

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问题 I have to upload a file from the front end and calculate the md5 hash of the file. I tried to use crypto.js to generate the md5 but for images it is giving me wrong md5. I saw a website called onlinemd5.com and it is exactly what I need. Can anyone help me how to calculate the md5 hash of a file(text file, images, videos etc) using javascript? Is it possible to download the code from http://onlinemd5.com and implement it? Note: I tried some of the suggestions in How to calculate md5 hash of a

Generate a md5 sum from an Android Bitmap object

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问题 I've spent several hours trying to figure out how to do this. I've read post after post here on stackoverflow and the documentation. I have a android.graphics.Bitmap object and I need to get it's md5 sum. At the point that I want to verify the sum it has not been saved to the file system. I've seen several ways of doing this for java.io.File objects. I just need a function that receives a Bitmap object and returns the hex md5 sum as a String. This might have been addressed somewhere but if it

How to mimic computeHash vb function in PHP

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I am having a hell of a time trying to md5 hash this with PHP... The VB code I am trying to port to PHP uses ComputeHash which takes in a byte[] and performs a hash on the whole array. Public Shared Function HashBytesMD5(ByVal strInput As String) As Guid Dim oHasher As Cryptography.MD5 = Cryptography.MD5.Create() Dim oEncoder As New System.Text.UTF8Encoding() Dim csData() As Byte csData = oEncoder.GetBytes(strInput) csData = oHasher.ComputeHash(oEncoder.GetBytes(strInput)) Return New Guid(csData) End Function Right now I have the following which creates an array of ascii values. Now I need to

Optimise updating MD5/SHA1 with streams of zeros

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问题 Is it possible to optimise the function: MD5_Update(&ctx_d, buf, num); if you know that buf contains only zeros? Or is this mathematically impossible? Likewise for SHA1. 回答1: If you control the input of the hash function then you could use a simple count instead of all the zero's, maybe using some kind of escape. E.g. 000020 in hex could mean 32 zero's. A (very) basic compression function may be much faster than MD5 or SHA1. Obviously this solution will only be faster if you save one or more

MD5 in Oracle (DBMS_OBFUSCATION_TOOLKIT.MD5)

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问题 I'm trying to compose a function to obtain MD5 hashes from bits I've gathered here and there. I want to obtain the lower-case hexadecimal representation of the hash. I have this so far: CREATE OR REPLACE FUNCTION MD5 ( CADENA IN VARCHAR2 ) RETURN DBMS_OBFUSCATION_TOOLKIT.VARCHAR2_CHECKSUM AS BEGIN RETURN LOWER( RAWTOHEX( UTL_RAW.CAST_TO_RAW( DBMS_OBFUSCATION_TOOLKIT.MD5(INPUT_STRING => CADENA) ) ) ); END; I'm not sure about the return type of the function. DBMS_OBFUSCATION_TOOLKIT.VARCHAR2