Criptografia
Publicado por amim 15/04/2004
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Esse algoritimo é muito bom, o MD5 é um algoritimo unidirecional ou seja você não consegue decriptografar a senha apenas compara-las, ele é usado na maioria das vezes no FreeBSD. É um algoritimo também usado na comparação do tamanho de arquivos, e mesmo assim é mais confiável do que o DES. Todos os direitos reservados (c) COPYRIGHT MIT and INRIA, 1996.
// Md5.java // $Id: Md5.java,v 1.5 2000/08/16 21:37:48 ylafon Exp $ // (c) COPYRIGHT MIT and INRIA, 1996. // Please first read the full copyright statement in file COPYRIGHT.html package org.w3c.tools.crypt ; import java.io.ByteArrayInputStream; import java.io.File; import java.io.FileInputStream; import java.io.IOException; import java.io.InputStream; import java.io.PrintStream; import java.io.UnsupportedEncodingException; public class Md5 { private static final int BUFFER_SIZE = 1024 ; private static final int S11 = 7 ; private static final int S12 = 12 ; private static final int S13 = 17 ; private static final int S14 = 22 ; private static final int S21 = 5 ; private static final int S22 = 9 ; private static final int S23 = 14 ; private static final int S24 = 20 ; private static final int S31 = 4 ; private static final int S32 = 11 ; private static final int S33 = 16 ; private static final int S34 = 23 ; private static final int S41 = 6 ; private static final int S42 = 10 ; private static final int S43 = 15 ; private static final int S44 = 21 ; private static byte padding[] = { (byte) 0x80, (byte) 0, (byte) 0, (byte) 0, (byte) 0, (byte) 0, (byte) 0, (byte) 0, (byte) 0, (byte) 0, (byte) 0, (byte) 0, (byte) 0, (byte) 0, (byte) 0, (byte) 0, (byte) 0, (byte) 0, (byte) 0, (byte) 0, (byte) 0, (byte) 0, (byte) 0, (byte) 0, (byte) 0, (byte) 0, (byte) 0, (byte) 0, (byte) 0, (byte) 0, (byte) 0, (byte) 0, (byte) 0, (byte) 0, (byte) 0, (byte) 0, (byte) 0, (byte) 0, (byte) 0, (byte) 0, (byte) 0, (byte) 0, (byte) 0, (byte) 0, (byte) 0, (byte) 0, (byte) 0, (byte) 0, (byte) 0, (byte) 0, (byte) 0, (byte) 0, (byte) 0, (byte) 0, (byte) 0, (byte) 0, (byte) 0, (byte) 0, (byte) 0, (byte) 0, (byte) 0, (byte) 0, (byte) 0, (byte) 0 } ; private InputStream in = null ; private boolean stringp = false ; private int state[] = null ; private long count = 0 ; private byte buffer[] = null ; private byte digest[] = null ; private static String stringify (byte buf[]) { StringBuffer sb = new StringBuffer(2*buf.length) ; for (int i = 0 ; i < buf.length; i++) { int h = (buf[i] & 0xf0) >> 4 ; int l = (buf[i] & 0x0f) ; sb.append (new Character((char)((h>9) ? 'a'+h-10 : '0'+h))) ; sb.append (new Character((char)((l>9) ? 'a'+l-10 : '0'+l))) ; } return sb.toString() ; } private final int F(int x, int y, int z) { return ((x & y) | ((~x) & z)) ; } private final int G(int x, int y, int z) { return ((x & z) | (y & (~z))) ; } private final int H(int x, int y, int z) { return (x ^ y ^ z) ; } private final int I(int x, int y, int z) { return (y ^ (x | (~z))) ; } private final int rotate_left(int x, int n) { return ((x << n) | (x >>> (32-n))) ; } private final int FF(int a,int b,int c,int d,int x,int s,int ac) { a += (F(b, c, d) + x + ac) ; a = rotate_left(a, s) ; a += b ; return a ; } private final int GG(int a,int b,int c,int d,int x,int s,int ac) { a += (G(b, c, d) + x + ac) ; a = rotate_left(a, s) ; a += b ; return a ; } private final int HH(int a,int b,int c,int d,int x,int s,int ac) { a += (H(b, c, d) + x + ac) ; a = rotate_left(a, s) ; a += b ; return a ; } private final int II(int a,int b,int c,int d,int x,int s,int ac) { a += (I(b, c, d) + x + ac) ; a = rotate_left(a, s) ; a += b ; return a; } private final void decode (int output[], byte input[], int off, int len) { int i = 0 ; int j = 0 ; for ( ; j < len; i++, j += 4) { output[i] = (((int) (input[off+j]&0xff)) | (((int) (input[off+j+1] & 0xff)) << 8) | (((int) (input[off+j+2] & 0xff)) << 16) | (((int) (input[off+j+3] & 0xff)) << 24)) ; } } private final void transform (byte block[], int offset) { int a = state[0] ; int b = state[1] ; int c = state[2] ; int d = state[3] ; int x[] = new int[16] ; decode (x, block, offset, 64); /* Round 1 */ a = FF (a, b, c, d, x[ 0], S11, 0xd76aa478); /* 1 */ d = FF (d, a, b, c, x[ 1], S12, 0xe8c7b756); /* 2 */ c = FF (c, d, a, b, x[ 2], S13, 0x242070db); /* 3 */ b = FF (b, c, d, a, x[ 3], S14, 0xc1bdceee); /* 4 */ a = FF (a, b, c, d, x[ 4], S11, 0xf57c0faf); /* 5 */ d = FF (d, a, b, c, x[ 5], S12, 0x4787c62a); /* 6 */ c = FF (c, d, a, b, x[ 6], S13, 0xa8304613); /* 7 */ b = FF (b, c, d, a, x[ 7], S14, 0xfd469501); /* 8 */ a = FF (a, b, c, d, x[ 8], S11, 0x698098d8); /* 9 */ d = FF (d, a, b, c, x[ 9], S12, 0x8b44f7af); /* 10 */ c = FF (c, d, a, b, x[10], S13, 0xffff5bb1); /* 11 */ b = FF (b, c, d, a, x[11], S14, 0x895cd7be); /* 12 */ a = FF (a, b, c, d, x[12], S11, 0x6b901122); /* 13 */ d = FF (d, a, b, c, x[13], S12, 0xfd987193); /* 14 */ c = FF (c, d, a, b, x[14], S13, 0xa679438e); /* 15 */ b = FF (b, c, d, a, x[15], S14, 0x49b40821); /* 16 */ /* Round 2 */ a = GG (a, b, c, d, x[ 1], S21, 0xf61e2562); /* 17 */ d = GG (d, a, b, c, x[ 6], S22, 0xc040b340); /* 18 */ c = GG (c, d, a, b, x[11], S23, 0x265e5a51); /* 19 */ b = GG (b, c, d, a, x[ 0], S24, 0xe9b6c7aa); /* 20 */ a = GG (a, b, c, d, x[ 5], S21, 0xd62f105d); /* 21 */ d = GG (d, a, b, c, x[10], S22, 0x2441453); /* 22 */ c = GG (c, d, a, b, x[15], S23, 0xd8a1e681); /* 23 */ b = GG (b, c, d, a, x[ 4], S24, 0xe7d3fbc8); /* 24 */ a = GG (a, b, c, d, x[ 9], S21, 0x21e1cde6); /* 25 */ d = GG (d, a, b, c, x[14], S22, 0xc33707d6); /* 26 */ c = GG (c, d, a, b, x[ 3], S23, 0xf4d50d87); /* 27 */ b = GG (b, c, d, a, x[ 8], S24, 0x455a14ed); /* 28 */ a = GG (a, b, c, d, x[13], S21, 0xa9e3e905); /* 29 */ d = GG (d, a, b, c, x[ 2], S22, 0xfcefa3f8); /* 30 */ c = GG (c, d, a, b, x[ 7], S23, 0x676f02d9); /* 31 */ b = GG (b, c, d, a, x[12], S24, 0x8d2a4c8a); /* 32 */ /* Round 3 */ a = HH (a, b, c, d, x[ 5], S31, 0xfffa3942); /* 33 */ d = HH (d, a, b, c, x[ 8], S32, 0x8771f681); /* 34 */ c = HH (c, d, a, b, x[11], S33, 0x6d9d6122); /* 35 */ b = HH (b, c, d, a, x[14], S34, 0xfde5380c); /* 36 */ a = HH (a, b, c, d, x[ 1], S31, 0xa4beea44); /* 37 */ d = HH (d, a, b, c, x[ 4], S32, 0x4bdecfa9); /* 38 */ c = HH (c, d, a, b, x[ 7], S33, 0xf6bb4b60); /* 39 */ b = HH (b, c, d, a, x[10], S34, 0xbebfbc70); /* 40 */ a = HH (a, b, c, d, x[13], S31, 0x289b7ec6); /* 41 */ d = HH (d, a, b, c, x[ 0], S32, 0xeaa127fa); /* 42 */ c = HH (c, d, a, b, x[ 3], S33, 0xd4ef3085); /* 43 */ b = HH (b, c, d, a, x[ 6], S34, 0x4881d05); /* 44 */ a = HH (a, b, c, d, x[ 9], S31, 0xd9d4d039); /* 45 */ d = HH (d, a, b, c, x[12], S32, 0xe6db99e5); /* 46 */ c = HH (c, d, a, b, x[15], S33, 0x1fa27cf8); /* 47 */ b = HH (b, c, d, a, x[ 2], S34, 0xc4ac5665); /* 48 */ /* Round 4 */ a = II (a, b, c, d, x[ 0], S41, 0xf4292244); /* 49 */ d = II (d, a, b, c, x[ 7], S42, 0x432aff97); /* 50 */ c = II (c, d, a, b, x[14], S43, 0xab9423a7); /* 51 */ b = II (b, c, d, a, x[ 5], S44, 0xfc93a039); /* 52 */ a = II (a, b, c, d, x[12], S41, 0x655b59c3); /* 53 */ d = II (d, a, b, c, x[ 3], S42, 0x8f0ccc92); /* 54 */ c = II (c, d, a, b, x[10], S43, 0xffeff47d); /* 55 */ b = II (b, c, d, a, x[ 1], S44, 0x85845dd1); /* 56 */ a = II (a, b, c, d, x[ 8], S41, 0x6fa87e4f); /* 57 */ d = II (d, a, b, c, x[15], S42, 0xfe2ce6e0); /* 58 */ c = II (c, d, a, b, x[ 6], S43, 0xa3014314); /* 59 */ b = II (b, c, d, a, x[13], S44, 0x4e0811a1); /* 60 */ a = II (a, b, c, d, x[ 4], S41, 0xf7537e82); /* 61 */ d = II (d, a, b, c, x[11], S42, 0xbd3af235); /* 62 */ c = II (c, d, a, b, x[ 2], S43, 0x2ad7d2bb); /* 63 */ b = II (b, c, d, a, x[ 9], S44, 0xeb86d391); /* 64 */ state[0] += a; state[1] += b; state[2] += c; state[3] += d; } private final void update (byte input[], int len) { int index = ((int) (count >> 3)) & 0x3f ; count += (len << 3) ; int partLen = 64 - index ; int i = 0 ; if ( len >= partLen ) { System.arraycopy (input, 0, buffer, index, partLen) ; transform (buffer, 0) ; for (i = partLen ; i + 63 < len ; i+= 64) transform (input, i) ; index = 0 ; } else { i = 0 ; } System.arraycopy (input, i, buffer, index, len - i) ; } private byte[] end () { byte bits[] = new byte[8] ; for (int i = 0 ; i < 8 ; i++) bits[i] = (byte) ((count>>>(i*8)) & 0xff) ; int index = ((int) (count >> 3)) & 0x3f ; int padlen = (index < 56) ? (56 - index) : (120 - index) ; update (padding, padlen) ; update (bits, 8) ; return encode(state, 16) ; } // Encode the content.state array into 16 bytes array private byte[] encode (int input[], int len) { byte output[] = new byte[len] ; int i = 0 ; int j = 0 ; for ( ; j < len ; i++, j+= 4) { output[j] = (byte) ((input[i] ) & 0xff) ; output[j+1] = (byte) ((input[i] >> 8 ) & 0xff) ; output[j+2] = (byte) ((input[i] >> 16) & 0xff) ; output[j+3] = (byte) ((input[i] >> 24) & 0xff) ; } return output ; } /** * Get the digest for our input stream. * This method constructs the input stream digest, and return it, as a * a String, following the MD5 (rfc1321) algorithm, * @return An instance of String, giving the message digest. * @exception IOException Thrown if the digestifier was unable to read the * input stream. */ public byte[] getDigest () throws IOException { byte buffer[] = new byte[BUFFER_SIZE] ; int got = -1 ; if ( digest != null ) return digest ; while ((got = in.read(buffer)) > 0 ) update (buffer, got) ; this.digest = end () ; return digest ; } /** * Get the digest, for this string digestifier. * This method doesn't throw any IOException, since it knows that the * underlying stream ws built from a String. */ public byte[] processString () { if ( ! stringp ) throw new RuntimeException (this.getClass().getName() + "[processString]" + " not a string.") ; try { return getDigest() ; } catch (IOException ex) { } throw new RuntimeException (this.getClass().getName() + "[processString]" + ": implementation error.") ; } /** * Get the digest, as a proper string. */ public String getStringDigest() { if ( digest == null ) throw new RuntimeException (this.getClass().getName() + "[getStringDigest]" + ": called before processing.") ; return stringify (digest) ; } /** * Construct a digestifier for the given string. * @param input The string to be digestified. * @param encoding the encoding name used (such as UTF8) */ public Md5 (String input, String enc) { byte bytes [] = null; try { bytes = input.getBytes (enc); } catch(UnsupportedEncodingException e){ throw new RuntimeException("no "+enc+" encoding!!!"); } this.stringp = true ; this.in = new ByteArrayInputStream (bytes) ; this.state = new int[4] ; this.buffer = new byte[64] ; this.count = 0 ; state[0] = 0x67452301; state[1] = 0xefcdab89; state[2] = 0x98badcfe; state[3] = 0x10325476; } /** * Construct a digestifier for the given string. * @param input The string to be digestified. */ public Md5 (String input) { this(input, "UTF8"); } /** * Construct a digestifier for the given input stream. * @param in The input stream to be digestified. */ public Md5 (InputStream in) { this.stringp = false ; this.in = in ; this.state = new int[4] ; this.buffer = new byte[64] ; this.count = 0 ; state[0] = 0x67452301; state[1] = 0xefcdab89; state[2] = 0x98badcfe; state[3] = 0x10325476; } public static void main (String args[]) throws IOException { if ( args.length != 1) { System.out.println ("Md5 <file>") ; System.exit (1) ; } Md5 md5 = new Md5 (new FileInputStream(new File(args[0]))) ; byte b[]= md5.getDigest(); System.out.println (stringify(b)) ; } }
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