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Convert a long to HEX value and the other way around

Handy to convert MD5 or SHA-1 hash values.

	public static long hexToLong(byte[] bytes) {

		if (bytes.length > 16) {
			throw new IllegalArgumentException("Byte array too long (max 16 elements)");
		}
		long v = 0;
		for (int i = 0; i < bytes.length; i += 2) {
			byte b1 = (byte) (bytes[i] & 0xFF);

			b1 -= 48;
			if (b1 > 9) b1 -= 39;

			if (b1 < 0 || b1 > 15) {
				throw new IllegalArgumentException("Illegal hex value: " + bytes[i]);
			}

			b1 <<=4;

			byte b2 = (byte) (bytes[i + 1] & 0xFF);
			b2 -= 48;
			if (b2 > 9) b2 -= 39;

			if (b2 < 0 || b2 > 15) {
				throw new IllegalArgumentException("Illegal hex value: " + bytes[i + 1]);
			}

			v |= (((b1 & 0xF0) | (b2 & 0x0F))) & 0x00000000000000FFL ;

			if (i + 2 < bytes.length) v <<= 8;
		}

		return v;
	}

	public static byte[] longToHex(final long l) {
		long v = l & 0xFFFFFFFFFFFFFFFFL;

		byte[] result = new byte[16];
		Arrays.fill(result, 0, result.length, (byte)0);

		for (int i = 0; i < result.length; i += 2) {
			byte b = (byte) ((v & 0xFF00000000000000L) >> 56);

			byte b2 = (byte) (b & 0x0F);
			byte b1 = (byte) ((b >> 4) & 0x0F);

			if (b1 > 9) b1 += 39;
			b1 += 48;

			if (b2 > 9) b2 += 39;
			b2 += 48;

			result[i] = (byte) (b1 & 0xFF);
			result[i + 1] = (byte) (b2 & 0xFF);

			v <<= 8;
		}

		return result;
	}


And tests:

	public void testHexToLong() throws Exception {
		assertEquals(-7057002501900618110L, NumberUtils.hexToLong("9e107d9d372bb682".getBytes()));
		assertEquals(-10908158098650842L, NumberUtils.hexToLong("ffd93f1687604926".getBytes()));
	}

	public void testLongToHex() throws Exception {
		assertEquals("9e107d9d372bb682", new String(NumberUtils.longToHex(-7057002501900618110L)));
		assertEquals("ffd93f1687604926", new String(NumberUtils.longToHex(-10908158098650842L)));
	}
to encryption java md5 shift bit SHA-1 by devijvers on Sep 30, 2007 1 Comments

Calculate MD5 hash

// description of your code here
http://blogs.msdn.com/csharpfaq/archive/2006/10/09/How-do-I-calculate-a-MD5-hash-from-a-string_3F00_.aspx

public string CalculateMD5Hash(string input)
{
    // step 1, calculate MD5 hash from input
    MD5 md5 = System.Security.Cryptography.MD5.Create();
    byte[] inputBytes = System.Text.Encoding.ASCII.GetBytes(input);
    byte[] hash = md5.ComputeHash(inputBytes);
 
    // step 2, convert byte array to hex string
    StringBuilder sb = new StringBuilder();
    for (int i = 0; i < hash.Length; i++)
    {
        sb.Append(hash[i].ToString("X2"));
    }
    return sb.ToString();
}
to md5 csharp by Edgardo on Jun 06, 2007

How to identify files which are identical in a directory

I use this script to find identical files with different names on a folder. It is very usefull to when you want to check your media collection for duplicates items. Basically it scans the directory and its subfolders, computes the md5 sum for each file, and keep them in a hash so they can be compared. The buffer size can be bigger or smaller, regarding the amount of memory you want to use. For large directories it can take a while to run, but it worked fine, at least for my 20+GB pictures collection.
#!/usr/local/bin/ruby
require 'digest/md5'
require 'digest/sha1'

$BUF_SIZE = 1024*1024*1024

class Folder_Md5
	
	def initialize(folder)
		@md5_to_files = Hash.new	
		@folder = folder
	end	
		
	def scan
		@md5_to_files.clear
		compute_md5(@folder)
	end		
	
	def md5_for_file(file_path)
		@md5_to_files[file_path]
	end	
	
	def identical_count
		total = 0
		@md5_to_files.each_value do |value|
				if value.size >= 2
					total+= value.size		
				end 
			end
		return total	
	end	
	
	def list_identical
		total = 0
		identities = 0
		puts 'The List of identical files'
		@md5_to_files.each_value do |value|
				if value.size >= 2
					identities+=1
					total+= value.size
					puts 'Idenitical files:'
					value.each{|file_name| puts file_name}
				end 
			end
		puts "got #{identities} identities impling #{total} files"
	end
	
	private	
		def compute_md5(file_path)
			if File.directory?(file_path)
				crt_dir = Dir.new(file_path)
				crt_dir.each do |file_name|
					if file_name != '.' &&  file_name != '..'				
						compute_md5("#{crt_dir.path}#{file_name}")		
					end
				end	
			else
				md5_val = md5(file_path)
				if @md5_to_files[md5_val] == nil
					@md5_to_files[md5_val]  = [file_path]	
				else					
					 @md5_to_files[md5_val] << file_path
				end		
			end
		end
		
		def md5(file_path)
			hasher = Digest::MD5.new
			open(file_path, "r") do |io|
				counter = 0
				while (!io.eof)
					readBuf = io.readpartial($BUF_SIZE)
					putc '.' if ((counter+=1) % 3 == 0)
					hasher.update(readBuf)
				end
			end			
			return hasher.hexdigest
		end	
end

worker = Folder_Md5.new(ARGV[0])
worker.scan
worker.list_identical
to ruby md5 file checksum by motoras on Apr 23, 2007

Get MD5 hash in a few lines of Java

// MD5 in Java, short and sweet version.

    1 import java.security.*;
    2 import java.math.*;
    3 
    4 public class MD5 {
    5    public static void main(String args[]) throws Exception{
    6       String s="This is a test";
    7       MessageDigest m=MessageDigest.getInstance("MD5");
    8       m.update(s.getBytes(),0,s.length());
    9       System.out.println("MD5: "+new BigInteger(1,m.digest()).toString(16));
   10    }
   11 }
to java md5 by gmiller on Mar 18, 2007

Java - String2MD5

public static byte[] getKeyedDigest(byte[] buffer, byte[] key) {
   try {
      MessageDigest md5 = MessageDigest.getInstance("MD5");
      md5.update(buffer);
      return md5.digest(key);
   } catch (NoSuchAlgorithmException nsae) {}

   return null;
}
to hash java string md5 text by whitetiger on Feb 28, 2007

MD5 and SHA1 in Ruby

// A Simple MD5/SHA1 calculator in Ruby

#!/usr/bin/ruby1.8 -w

#
# A Simple Hash Code Calculator
# Returns SHA1 and MD5 hash for any given file
# Author: Alessio Saltarin
#

require 'digest/md5'
require 'digest/sha1'

$BUFLEN = 1024

class Hasher
	# Constructor
	# method = "SHA1" or "MD5"
	# filepath = Full filepath
	def initialize(method, filepath)
		if (method.upcase == "-SHA1")
			@hashfunc = Digest::SHA1.new
			@hashname = "SHA1"
		else
			@hashfunc = Digest::MD5.new
			@hashname = "MD5"
		end
		@fullfilename = filepath
	end

	def hashname
		@hashname
	end

	# Compute hash code
	def hashsum
		open(@fullfilename, "r") do |io|
			puts "Reading "+@fullfilename
			counter = 0
			while (!io.eof)
				readBuf = io.readpartial($BUFLEN)
				putc '.' if ((counter+=1) % 3 == 0)
				@hashfunc.update(readBuf)
			end
		end
		return @hashfunc.hexdigest
	end
end

def usage
	puts "Usage: Hasher.rb [-SHA1|-MD5] filename"
end

def printresult(filename, method, sum)
	puts "\n" + filename + " ==> "+ method + ": " + sum	
end

#Program starts
if (ARGV.length == 2)
	hashcomp = Hasher.new(ARGV[0], ARGV[1])
	printresult(ARGV[1], hashcomp.hashname, hashcomp.hashsum)
	
elsif (ARGV.length == 1)
	hashcomp = Hasher.new("-MD5", ARGV[0])
	printresult(ARGV[0], hashcomp.hashname, hashcomp.hashsum)
else
	usage
end
to ruby sha1 md5 by axsaxs on Jan 23, 2007

md5 digest hash in newLISP

;;; md5 in newLISP

;;
;; based on RFC 1321
;;


(define (F x y z)
  (| (& x y) (& (& 0xffffffff (~ x)) z)))

(define (G x y z)
  (| (& x z) (& y (& 0xffffffff (~ z)))))

(define (H x y z)
  (^ x y z))

(define (I x y z)
  (^ y (| x (& 0xffffffff (~ z)))))

(define (rotate-left x n)
  (| (& 0xffffffff (<< x n)) (& 0xffffffff (>> x (- 32 n)))))

(define (FF a b c d x s ac)
  (set 'a (& 0xffffffff (+ a (F b c d) x ac)))
  (set 'a (rotate-left a s))
  (set 'a (& 0xffffffff (+ a b))))

(define (GG a b c d x s ac)
  (set 'a (& 0xffffffff (+ a (G b c d) x ac)))
  (set 'a (rotate-left a s))
  (set 'a (& 0xffffffff (+ a b))))

(define (HH a b c d x s ac)
  (set 'a (& 0xffffffff (+ a (H b c d) x ac)))
  (set 'a (rotate-left a s))
  (set 'a (& 0xffffffff (+ a b))))

(define (II a b c d x s ac)
  (set 'a (& 0xffffffff (+ a (I b c d) x ac)))
  (set 'a (rotate-left a s))
  (set 'a (& 0xffffffff (+ a b))))

(define (md5-init )
  (set 'md5-i '(0 0))
  (set 'md5-in (dup 0 64))
  (set 'md5-digest (dup 0 16))
  (set 'md5-buf '(0x67452301 0xefcdab89 0x98badcfe 0x10325476)))

(define (md5-update inbuf inlen)
  ;; compute number of bytes mod 64
  (set 'mdi (& (>> (md5-i 0) 3) 0x3f))

  ;; update number of bits
  (if (< (+ (md5-i 0)  (<< inlen 3)) (md5-i 0))
      (nth-set (md5-i 1) (+ 1 (md5-i 1))))

  (nth-set (md5-i 0) (+ (md5-i 0) (<< inlen 3)))
  (nth-set (md5-i 1) (+ (md5-i 1) (>> inlen 29)))

  (set 'inbuf-index 0)
  (while (> inlen 0)
	 ;; add new character to buffer, increment mdi
	 (nth-set (md5-in mdi) (inbuf inbuf-index))
	 (set 'mdi (+ mdi 1))
	 (set 'inbuf-index (+ inbuf-index 1))

	 ;; transform if necessary
	 (if (= mdi 0x40)
	     (begin
	       (set 'ii 0)
	       (set 'in (dup 0 16))
	       (for (i 0 15 1)
		    (nth-set (in i) (| (<< (char->int (md5-in (+ ii 3))) 24)
				       (<< (char->int (md5-in (+ ii 2))) 16)
				       (<< (char->int (md5-in (+ ii 1))) 8)
				       (char->int (md5-in ii))))
		    (set 'ii (+ ii 4)))
	       (transform  in)
	       (set 'mdi 0)))
	 (set 'inlen (- inlen 1))))

(define (char->int x)
  (if (integer? x) x (char x)))

(define (md5-final)
  (set 'in (dup 0 16))

  ;; save number of bits
  (nth-set (in 14) (md5-i 0))
  (nth-set (in 15) (md5-i 1))

  ;; compute number of bytse mod 64
  (set 'mdi (& (>> (md5-i 0) 3) 0x3f))

  ;; pad out to 56 mod 64
  (if (< mdi 56)
      (set 'padlen (- 56 mdi))
      (set 'padlen (- 120 mdi)))

  (set 'padding (dup 0 64))
  (nth-set (padding 0) 0x80)
  (md5-update padding padlen)

  ;; append lenth in bits and transform
  (set 'ii 0)
  (for (i 0 13 1)
       (nth-set (in i) (| (<< (char->int (md5-in (+ ii 3))) 24)
			  (<< (char->int (md5-in (+ ii 2))) 16)
			  (<< (char->int (md5-in (+ ii 1))) 8) (char->int (md5-in ii))))
       (set 'ii (+ ii 4)))
  (transform in)

  ;; store buffer in digest
  (set 'ii 0)
  (for (i 0 3 1)
       (nth-set (md5-digest ii) (& (md5-buf i) 0xff))
       (nth-set (md5-digest (+ ii 1)) (& (>> (md5-buf i) 8) 0xff))
       (nth-set (md5-digest (+ ii 2)) (& (>> (md5-buf i) 16)  0xff))
       (nth-set (md5-digest (+ ii 3)) (& (>> (md5-buf i) 24)  0xff))
       (set 'ii (+ ii 4))))

(define (transform  in)
  (set 'a (md5-buf 0))
  (set 'b (md5-buf 1))
  (set 'c (md5-buf 2))
  (set 'd (md5-buf 3))

  ;; Round 1
  (set 'S11 7)
  (set 'S12 12)
  (set 'S13 17)
  (set 'S14 22)
  (set 'a (FF a b c d (in 0) S11 3614090360)) 
  (set 'd (FF d a b c (in 1) S12 3905402710)) 
  (set 'c (FF c d a b (in 2) S13  606105819)) 
  (set 'b (FF b c d a (in 3) S14 3250441966)) 
  (set 'a (FF a b c d (in 4) S11 4118548399)) 
  (set 'd (FF d a b c (in 5) S12 1200080426)) 
  (set 'c (FF c d a b (in 6) S13 2821735955)) 
  (set 'b (FF b c d a (in 7) S14 4249261313)) 
  (set 'a (FF a b c d (in 8) S11 1770035416)) 
  (set 'd (FF d a b c (in 9) S12 2336552879)) 
  (set 'c (FF c d a b (in 10) S13 4294925233))
  (set 'b (FF b c d a (in 11) S14 2304563134))
  (set 'a (FF a b c d (in 12) S11 1804603682))
  (set 'd (FF d a b c (in 13) S12 4254626195))
  (set 'c (FF c d a b (in 14) S13 2792965006))
  (set 'b (FF b c d a (in 15) S14 1236535329))

  ;; Round 2 
  (set 'S21 5)
  (set 'S22 9)
  (set 'S23 14)
  (set 'S24 20)
  (set 'a (GG a b c d (in 1) S21 4129170786)) 
  (set 'd (GG d a b c (in 6) S22 3225465664)) 
  (set 'c (GG c d a b (in 11) S23  643717713))
  (set 'b (GG b c d a (in 0) S24 3921069994)) 
  (set 'a (GG a b c d (in 5) S21 3593408605)) 
  (set 'd (GG d a b c (in 10) S22   38016083))
  (set 'c (GG c d a b (in 15) S23 3634488961))
  (set 'b (GG b c d a (in 4) S24 3889429448)) 
  (set 'a (GG a b c d (in 9) S21  568446438)) 
  (set 'd (GG d a b c (in 14) S22 3275163606))
  (set 'c (GG c d a b (in 3) S23 4107603335)) 
  (set 'b (GG b c d a (in 8) S24 1163531501)) 
  (set 'a (GG a b c d (in 13) S21 2850285829))
  (set 'd (GG d a b c (in 2) S22 4243563512)) 
  (set 'c (GG c d a b (in 7) S23 1735328473)) 
  (set 'b (GG b c d a (in 12) S24 2368359562))

  ;; Round 3 
  (set 'S31 4)
  (set 'S32 11)
  (set 'S33 16)
  (set 'S34 23)
  (set 'a (HH a b c d (in 5) S31 4294588738)) 
  (set 'd (HH d a b c (in 8) S32 2272392833)) 
  (set 'c (HH c d a b (in 11) S33 1839030562))
  (set 'b (HH b c d a (in 14) S34 4259657740))
  (set 'a (HH a b c d (in 1) S31 2763975236)) 
  (set 'd (HH d a b c (in 4) S32 1272893353)) 
  (set 'c (HH c d a b (in 7) S33 4139469664)) 
  (set 'b (HH b c d a (in 10) S34 3200236656))
  (set 'a (HH a b c d (in 13) S31  681279174))
  (set 'd (HH d a b c (in 0) S32 3936430074)) 
  (set 'c (HH c d a b (in 3) S33 3572445317)) 
  (set 'b (HH b c d a (in 6) S34   76029189)) 
  (set 'a (HH a b c d (in 9) S31 3654602809)) 
  (set 'd (HH d a b c (in 12) S32 3873151461))
  (set 'c (HH c d a b (in 15) S33  530742520))
  (set 'b (HH b c d a (in 2) S34 3299628645)) 

  ;; Round 4 
  (set 'S41 6)
  (set 'S42 10)
  (set 'S43 15)
  (set 'S44 21)
  (set 'a (II a b c d (in 0) S41 4096336452)) 
  (set 'd (II d a b c (in 7) S42 1126891415)) 
  (set 'c (II c d a b (in 14) S43 2878612391))
  (set 'b (II b c d a (in 5) S44 4237533241)) 
  (set 'a (II a b c d (in 12) S41 1700485571))
  (set 'd (II d a b c (in 3) S42 2399980690)) 
  (set 'c (II c d a b (in 10) S43 4293915773))
  (set 'b (II b c d a (in 1) S44 2240044497)) 
  (set 'a (II a b c d (in 8) S41 1873313359)) 
  (set 'd (II d a b c (in 15) S42 4264355552))
  (set 'c (II c d a b (in 6) S43 2734768916)) 
  (set 'b (II b c d a (in 13) S44 1309151649))
  (set 'a (II a b c d (in 4) S41 4149444226)) 
  (set 'd (II d a b c (in 11) S42 3174756917))
  (set 'c (II c d a b (in 2) S43  718787259)) 
  (set 'b (II b c d a (in 9) S44 3951481745)) 

  (nth-set (md5-buf 0) (+ a (md5-buf 0)))
  (nth-set (md5-buf 1) (+ b (md5-buf 1)))
  (nth-set (md5-buf 2) (+ c (md5-buf 2)))
  (nth-set (md5-buf 3) (+ d (md5-buf 3))))

(define (md5-string str)
  (md5-init)
  (md5-update str (length str))
  (md5-final)
  (set 'result "")
  (for (i 0 15 1)
       (set 'result (append result (format "%02x" (md5-digest i)))))
  result)
to hash md5 lisp newlisp digest by frontera000 on Sep 14, 2006

finding md5 in python

import md5
hash = md5.new("Hello world").digest()

more info here http://docs.python.org/lib/module-md5.html
to python hash md5 by korakot on Apr 12, 2005
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