As per MSDN Create MD5: public static string CreateMD5(string input) { // Use input string to calculate MD5 hash using (System.Security.Cryptography.MD5 md5 = System.Security.Cryptography.MD5.Create()) { byte[] inputBytes = System.Text.Encoding.ASCII.GetBytes(input); byte[] hashBytes = md5.ComputeHash(inputBytes); return Convert.ToHexString(hashBytes); // .NET 5 + // Convert the byte array to hexadecimal string prior to .NET 5 // StringBuilder sb = … Read more
I didn’t verify this myself, but you can look at this JavaScript implementation of Java’s String.hashCode() method. Seems reasonably short. With this prototype you can simply call .hashCode() on any string, e.g. “some string”.hashCode(), and receive a numerical hash code (more specifically, a Java equivalent) such as 1395333309. String.prototype.hashCode = function() { var hash = … Read more
It doesn’t decode an MD5 hash. It uses what’s called a rainbow table… That’s why it’s so important to use salted hashes instead of storing the hash directly…
You’re correct that it cannot guarantee uniqueness, however there are approximately 3.402823669209387e+38 different values in a 32 digit hex value (16^32). That means that, assuming the math behind the algorithm gives a good distribution, your odds are phenomenally small that there will be a duplicate. You do have to keep in mind that it IS … Read more
This is the category I use: NSString+MD5.h @interface NSString (MD5) – (NSString *)MD5String; @end NSString+MD5.m #import <CommonCrypto/CommonDigest.h> @implementation NSString (MD5) – (NSString *)MD5String { const char *cStr = [self UTF8String]; unsigned char result[CC_MD5_DIGEST_LENGTH]; CC_MD5( cStr, (CC_LONG)strlen(cStr), result ); return [NSString stringWithFormat: @”%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X”, result[0], result[1], result[2], result[3], result[4], result[5], result[6], result[7], result[8], result[9], result[10], result[11], result[12], … Read more
For a set of even billions of assets, the chances of random collisions are negligibly small — nothing that you should worry about. Considering the birthday paradox, given a set of 2^64 (or 18,446,744,073,709,551,616) assets, the probability of a single MD5 collision within this set is 50%. At this scale, you’d probably beat Google in … Read more
Here’s an example of how to read a file in chunks of 1KB without loading the entire contents into memory: const int chunkSize = 1024; // read the file by chunks of 1KB using (var file = File.OpenRead(“foo.dat”)) { int bytesRead; var buffer = new byte[chunkSize]; while ((bytesRead = file.Read(buffer, 0, buffer.Length)) > 0) { … Read more
Yes, MD5 is somewhat less CPU-intensive. On my Intel x86 (Core2 Quad Q6600, 2.4 GHz, using one core), I get this in 32-bit mode: MD5 411 SHA-1 218 SHA-256 118 SHA-512 46 and this in 64-bit mode: MD5 407 SHA-1 312 SHA-256 148 SHA-512 189 Figures are in megabytes per second, for a “long” message … Read more
You can use the HMACMD5 class: var hmacMD5 = new HMACMD5(salt); var saltedHash = hmacMD5.ComputeHash(password); Works with SHA-1, SHA256, SHA384, SHA512 and RIPEMD160 as well: var hmacSHA1 = new HMACSHA1(salt); var saltedHash = hmacSHA1.ComputeHash(password); Both salt and password are expected as byte arrays. If you have strings you’ll have to convert them to bytes first: … Read more
You use the TransformBlock and TransformFinalBlock methods to process the data in chunks. // Init MD5 md5 = MD5.Create(); int offset = 0; // For each block: offset += md5.TransformBlock(block, 0, block.Length, block, 0); // For last block: md5.TransformFinalBlock(block, 0, block.Length); // Get the has code byte[] hash = md5.Hash; Note: It works (at least … Read more