You could have a custom object containing the two strings: class StringKey { private String str1; private String str2; } Problem is, you need to determine the equality test and the hash code for two such objects. Equality could be the match on both strings and the hashcode could be the hashcode of the concatenated … Read more
MD5, like other hash functions, does not require two passes. To start: HashAlgorithm hasher = ..; hasher.Initialize(); As each block of data arrives: byte[] buffer = ..; int bytesReceived = ..; hasher.TransformBlock(buffer, 0, bytesReceived, null, 0); To finish and retrieve the hash: hasher.TransformFinalBlock(new byte[0], 0, 0); byte[] hash = hasher.Hash; This pattern works for any … Read more
Yes, not exhibiting any bias is a design requirement for a cryptographic hash. MD5 is broken from a cryptographic point of view however the distribution of the results was never in question. If you still need to be convinced, it’s not a huge undertaking to hash a bunch of files, truncate the output and use … Read more
You need to hash about 2^64 values to get a single collision among them, on average, if you don’t try to deliberately create collisions. Hash collisions are very similar to the Birthday problem. If you look at two arbitrary values, the collision probability is only 2-128. The problem with md5 is that it’s relatively easy … Read more
Unfortunately, this program has undefined behavior. C++11 ยง17.6.4.2.1: A program may add a template specialization for any standard library template to namespace std only if the declaration depends on a user-defined type and the specialization meets the standard library requirements for the original template and is not explicitly prohibited. hash<pair<int,int>> depends on primitive and standard … Read more
First things first: speed is overrated. You should make measures before declaring that a given algorithm is “too slow”. Most of the time, hash function speed makes no noticeable difference anyway. If you have qualms about security, then first select a hash function which is secure enough, and then only worry about performance. Moreover, you … Read more
ActiveSupport adds a to_xml method to Hash, so you can get pretty close to what you are looking for with this: sudo gem install activesupport require “active_support/core_ext” my_hash = { :first_name => ‘Joe’, :last_name => ‘Blow’, :email => ‘joe@example.com’} my_hash.to_xml(:root => ‘customer’) And end up with: <?xml version=”1.0″ encoding=”UTF-8″?> <customer> <last-name>Blow</last-name> <first-name>Joe</first-name> <email>joe@example.com</email> </customer> Note … Read more
You can do it in Swift. Just make sure you add #import <CommonCrypto/CommonHMAC.h> to the bridging Objective-C bridging header. Update: For Swift 4 see a much better solution using the Swift Package Manager here: https://github.com/jernejstrasner/SwiftCrypto enum CryptoAlgorithm { case MD5, SHA1, SHA224, SHA256, SHA384, SHA512 var HMACAlgorithm: CCHmacAlgorithm { var result: Int = 0 switch … Read more
MD5 is designed to be cryptographically irreversible. In this case, the most important property is that it is computationally unfeasible to find the reverse of a hash, but it is easy to find the hash of any data. For example, let’s think about just operating on numbers (binary files after all, could be interpreted as … Read more
This has very little to do with hash functions. A cryptographic hash function may be part of the implementation, but it’s not required. Actually, it generates the digits on a time-based interval, if I press the button for it to generate the digits, it generates the digits and after about 25 seconds, and I press … Read more