[+] MD5 adalah sebuah fungsi hash yang digunakan secara luas dengan ukuran hash value 128-bit
[+] Pertama kali ditemukan oleh professor Ronald Rivest dari Artificial Intelligence Lab Massachussets Institute of Technology
[+] Algoritma dikutip dari wikipedia
[+] Implementasi dalam bahasa-C
[+] Pertama kali ditemukan oleh professor Ronald Rivest dari Artificial Intelligence Lab Massachussets Institute of Technology
[+] Algoritma dikutip dari wikipedia
- Code:
- Seluruh variable pada unsigned integer 32-bit dan dan wrap modulo 2^32 saat melakukan perhitungan
Mendefinisikan r sebagai berikut
var int[64] r, k
r[ 0..15] := {7, 12, 17, 22, 7, 12, 17, 22, 7, 12, 17, 22, 7, 12, 17, 22}
r[16..31] := {5, 9, 14, 20, 5, 9, 14, 20, 5, 9, 14, 20, 5, 9, 14, 20}
r[32..47] := {4, 11, 16, 23, 4, 11, 16, 23, 4, 11, 16, 23, 4, 11, 16, 23}
r[48..63] := {6, 10, 15, 21, 6, 10, 15, 21, 6, 10, 15, 21, 6, 10, 15, 21}
Menggunakan bagian fraksional biner dari integral sinus sebagai konstanta:
for i from 0 to 63
k[i] := floor(abs(sin(i + 1)) × 2^32)
Inisialisasi variabel:
var int h0 := 0x67452301
var int h1 := 0xEFCDAB89
var int h2 := 0x98BADCFE
var int h3 := 0x10325476
Pemrosesan awal:
append "1" bit to message
append "0" bits until message length in bits ≡ 448 (mod 512)
append bit length of message as 64-bit little-endian integer to message
Pengolahan pesan paada kondisi gumpalan 512-bit:
for each 512-bit chunk of message
break chunk into sixteen 32-bit little-endian words w(i), 0 ≤ i ≤ 15
Inisialisasi nilai hash pada gumpalan ini:
var int a := h0
var int b := h1
var int c := h2
var int d := h3
Kalang utama:
for i from 0 to 63
if 0 ≤ i ≤ 15 then
f := (b and c) or ((not b) and d)
g := i
else if 16 ≤ i ≤ 31
f := (d and b) or ((not d) and c)
g := (5×i + 1) mod 16
else if 32 ≤ i ≤ 47
f := b xor c xor d
g := (3×i + 5) mod 16
else if 48 ≤ i ≤ 63
f := c xor (b or (not d))
g := (7×i) mod 16
temp := d
d := c
c := b
b := ((a + f + k(i) + w(g)) leftrotate r(i)) + b
a := temp
Tambahkan hash dari gumpalan sebagai hasil:
h0 := h0 + a
h1 := h1 + b
h2 := h2 + c
h3 := h3 + d
var int digest := h0 append h1 append h2 append h3 (diwujudkan dalam little-endian)
[+] Implementasi dalam bahasa-C
- Code:
/* md5_hashing_computation.c
* Real Algorithm by : Prof. Ronald Rivest (csail.mit.edu)
* Implementation By : Paulus Gandung Prakosa_ (0x1337day)
*/
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <conio.h>
typedef unsigned long int u_int32;
typedef unsigned int u_int;
/* struktur data untuk komputasi MD5 */
struct md5_global_requirements
{
// bit angka, hasil sisa bagi (2 pangkat 64)
u_int32 mod[2];
// penyangga gesekan (scratch buffer)
u_int32 buffer[4];
// penyangga masukan (input buffer)
unsigned char input[64];
// "digest" sesudah fungsi md5_hashing dipanggil
unsigned char hash_digest[16];
};
static void md5_initialization(struct md5_global_requirements *);
static void md5_update(struct md5_global_requirements *, unsigned char *, unsigned int);
static void md5_hashing(struct md5_global_requirements *);
static void transform(u_int32 *, u_int32 *);
static unsigned char hash_padding[64] =
{
0x80, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00
};
#define hashing_func1(x, y, z) (((x) & (y)) | ((~x) & (z)))
#define hashing_func2(x, y, z) (((x) & (z)) | ((y) & (~z)))
#define hashing_func3(x, y, z) ((x) ^ (y) ^(z))
#define hashing_func4(x, y, z) ((y) ^ ((x) | (~z)))
// fungsi "rotate_left" memutar variabel x sebanyak n bits
#define rotate_left(x, nbytes) (((x) << (nbytes)) | ((x) >> (32 - (nbytes))))
/* transform_1, transform_2, transform_3, transform_4 adalah fungsi
* untuk ronde 1, 2, 3, 4
* perputaran bit dipisahkan dari penambahan bit untuk mencegah
* komputasi ulang
*/
#define transform_1(a, b, c, d, x, s, fraction) \
{(a) += hashing_func1((b), (c), (d)) + (x) + (u_int32)(fraction); \
(a) = rotate_left ((a), (s)); \
(a) += (b); \
}
#define transform_2(a, b, c, d, x, s, fraction) \
{(a) += hashing_func2((b), (c), (d)) + (x) + (u_int32)(fraction); \
(a) = rotate_left ((a), (s)); \
(a) += (b); \
}
#define transform_3(a, b, c, d, x, s, fraction) \
{(a) += hashing_func3 ((b), (c), (d)) + (x) + (u_int32)(fraction); \
(a) = rotate_left ((a), (s)); \
(a) += (b); \
}
#define transform_4(a, b, c, d, x, s, fraction) \
{(a) += hashing_func4 ((b), (c), (d)) + (x) + (u_int32)(fraction); \
(a) = rotate_left ((a), (s)); \
(a) += (b); \
}
/* waktunya untuk penginisialiasian fungsi-fungsi berikut :
* - static void md5_initialization();
* - static void md5_update();
* - static void md5_hashing();
* - static void transform();
*/
static void md5_initialization(hash_req)
struct md5_global_requirements *hash_req;
{
/* set mod[0] dan mod[1] dengan nilai 0 */
hash_req->mod[0] = (u_int32)0;
hash_req->mod[1] = (u_int32)0;
/* inisialisasi angka ajaib yang bersifat konstan */
hash_req->buffer[0] = (u_int32)0x67452301;
hash_req->buffer[1] = (u_int32)0xefcdab89;
hash_req->buffer[2] = (u_int32)0x98badcfe;
hash_req->buffer[3] = (u_int32)0x10325476;
}
static void md5_update(hash_req, input_buffer, buffer_length)
struct md5_global_requirements *hash_req;
unsigned char *input_buffer;
unsigned int buffer_length;
{
u_int32 num[16];
int mod_64;
unsigned int loop1, loop2;
/* hitung sisa bagi (modulus) bytes dengan 64 */
mod_64 = (int)((hash_req->mod[0] >> 3) & 0x3f);
/* update number dari bit */
if ((hash_req->mod[0] + ((u_int32)buffer_length << 3)) < hash_req->mod[0])
{
hash_req->mod[1]++;
}
hash_req->mod[0] += ((u_int32)buffer_length << 3);
hash_req->mod[1] += ((u_int32)buffer_length >> 29);
while (buffer_length--)
{
/* tambahkan character baru ke dalam input_buffer dan naikkan nilai
* mod_64
*/
hash_req->input[mod_64++] = *input_buffer++;
/* ubah jika dibutuhkan */
if (mod_64 == 0x40)
{
for (loop1 = 0, loop2 = 0; loop1 < 16; loop1++, loop2 += 4)
{
num[loop1] = (((u_int32)hash_req->input[loop2 + 3]) << 24) |
(((u_int32)hash_req->input[loop2 + 2]) << 16) |
(((u_int32)hash_req->input[loop2 + 1]) << 8) |
((u_int32)hash_req->input[loop2]);
}
transform (hash_req->buffer, num);
mod_64 = 0;
}
}
}
static void md5_hashing(hash_req)
struct md5_global_requirements *hash_req;
{
u_int32 num[16];
int mod_64;
unsigned int loop1, loop2;
unsigned int padding_length;
/* simpan bit dari number */
num[14] = hash_req->mod[0];
num[15] = hash_req->mod[1];
/* hitung sisa bagi (modulus) bytes dengan 64 */
mod_64 = (int)((hash_req->mod[0] >> 3) & 0x3f);
/* tambahkan ke 56 yang disisabagikan dengan 64 */
padding_length = (mod_64 < 56) ? (56 - mod_64) : (120 - mod_64);
md5_update (hash_req, hash_padding, padding_length);
/* tambahkan panjang padding dengan bits dan ubah */
for (loop1 = 0, loop2 = 0; loop1 < 14; loop1++, loop2 += 4)
{
num[loop1] = (((u_int32)hash_req->input[loop2 + 3]) << 24) |
(((u_int32)hash_req->input[loop2 + 2]) << 16) |
(((u_int32)hash_req->input[loop2 + 1]) << 8) |
((u_int32)hash_req->input[loop2]);
}
transform (hash_req->buffer, num);
/* pindahkan buffer di "digest" */
for (loop1 = 0, loop2 = 0; loop1 < 4; loop1++, loop2 += 4)
{
hash_req->hash_digest[loop2] =
(unsigned char)(hash_req->buffer[loop1] & 0xff);
hash_req->hash_digest[loop2 + 1] =
(unsigned char)((hash_req->buffer[loop1] >> 8) & 0xff);
hash_req->hash_digest[loop2 + 2] =
(unsigned char)((hash_req->buffer[loop1] >> 16) & 0xff);
hash_req->hash_digest[loop2 + 3] =
(unsigned char)((hash_req->buffer[loop1] >> 24) & 0xff);
}
}
/* dasar langkah md5, mentransformasikan buffer yang ada
* di dalamnya
*/
static void transform(buffer, input)
u_int32 *buffer;
u_int32 *input;
{
u_int32 var1 = buffer[0];
u_int32 var2 = buffer[1];
u_int32 var3 = buffer[2];
u_int32 var4 = buffer[3];
/* variabel "fraction" yang ada dalam fungsi transform_1, transform_2,
* transform_3, dan transform_4 didapatkan dari fungsi berikut :
*
* hasil fraksional biner dari integral sinus sebagai konstanta
* for "i" from "0" to "63"
* k[i] = floor(abs(sin(i + 1)) * pow(2, 32);
*/
/* putaran 1 */
#define s11 7
#define s12 12
#define s13 17
#define s14 22
transform_1(var1, var2, var3, var4, input[0], s11, (u_int)3614090360);
transform_1(var4, var1, var2, var3, input[1], s12, (u_int)3905402710);
transform_1(var3, var4, var1, var2, input[2], s13, (u_int)606105819);
transform_1(var2, var3, var4, var1, input[3], s14, (u_int)3250441966);
transform_1(var1, var2, var3, var4, input[4], s11, (u_int)4118548399);
transform_1(var4, var1, var2, var3, input[5], s12, (u_int)1200080426);
transform_1(var3, var4, var1, var2, input[6], s13, (u_int)2821735955);
transform_1(var2, var3, var4, var1, input[7], s14, (u_int)4249261313);
transform_1(var1, var2, var3, var4, input[8], s11, (u_int)1770035416);
transform_1(var4, var1, var2, var3, input[9], s12, (u_int)2336552879);
transform_1(var3, var4, var1, var2, input[10], s13, (u_int)4294925233);
transform_1(var2, var3, var4, var1, input[11], s14, (u_int)2304563134);
transform_1(var1, var2, var3, var4, input[12], s11, (u_int)1804603682);
transform_1(var4, var1, var2, var3, input[13], s12, (u_int)4254626195);
transform_1(var3, var4, var1, var2, input[14], s13, (u_int)2792965006);
transform_1(var2, var3, var4, var1, input[15], s14, (u_int)1236535329);
/* putaran 2 */
#define s21 5
#define s22 9
#define s23 14
#define s24 20
transform_2(var1, var2, var3, var4, input[1], s21, (u_int)4129170786);
transform_2(var4, var1, var2, var3, input[6], s22, (u_int)3225465664);
transform_2(var3, var4, var1, var2, input[11], s23, (u_int)643717713);
transform_2(var2, var3, var4, var1, input[0], s24, (u_int)3921069994);
transform_2(var1, var2, var3, var4, input[5], s21, (u_int)3593408605);
transform_2(var4, var1, var2, var3, input[10], s22, (u_int)38016083);
transform_2(var3, var4, var1, var2, input[15], s23, (u_int)3634488961);
transform_2(var2, var3, var4, var1, input[4], s24, (u_int)3889429448);
transform_2(var1, var2, var3, var4, input[9], s21, (u_int)568446438);
transform_2(var4, var1, var2, var3, input[14], s22, (u_int)3275163606);
transform_2(var3, var4, var1, var2, input[3], s23, (u_int)4107603335);
transform_2(var2, var3, var4, var1, input[8], s24, (u_int)1163531501);
transform_2(var1, var2, var3, var4, input[13], s21, (u_int)2850285829);
transform_2(var4, var1, var2, var3, input[2], s22, (u_int)4243563512);
transform_2(var3, var4, var1, var2, input[7], s23, (u_int)1735328473);
transform_2(var2, var3, var4, var1, input[12], s24, (u_int)2368359562);
/* putaran 3 */
#define s31 4
#define s32 11
#define s33 16
#define s34 23
transform_3(var1, var2, var3, var4, input[5], s31, (u_int)4294588738);
transform_3(var4, var1, var2, var3, input[8], s32, (u_int)2272392833);
transform_3(var3, var4, var1, var2, input[11], s33, (u_int)1839030562);
transform_3(var2, var3, var4, var1, input[14], s34, (u_int)4259657740);
transform_3(var1, var2, var3, var4, input[1], s31, (u_int)2763975236);
transform_3(var4, var1, var2, var3, input[4], s32, (u_int)1272893353);
transform_3(var3, var4, var1, var2, input[7], s33, (u_int)4139469664);
transform_3(var2, var3, var4, var1, input[10], s34, (u_int)3200236656);
transform_3(var1, var2, var3, var4, input[13], s31, (u_int)681279174);
transform_3(var4, var1, var2, var3, input[0], s32, (u_int)3936430074);
transform_3(var3, var4, var1, var2, input[3], s33, (u_int)3572445317);
transform_3(var2, var3, var4, var1, input[6], s34, (u_int)76029189);
transform_3(var1, var2, var3, var4, input[9], s31, (u_int)3654602809);
transform_3(var4, var1, var2, var3, input[12], s32, (u_int)3873151461);
transform_3(var3, var4, var1, var2, input[15], s33, (u_int)530742520);
transform_3(var2, var3, var4, var1, input[2], s34, (u_int)3299628645);
/* putaran 4 */
#define s41 6
#define s42 10
#define s43 15
#define s44 21
transform_4(var1, var2, var3, var4, input[0], s41, (u_int)4096336452);
transform_4(var4, var1, var2, var3, input[7], s42, (u_int)1126891415);
transform_4(var3, var4, var1, var2, input[14], s43, (u_int)2878612391);
transform_4(var2, var3, var4, var1, input[5], s44, (u_int)4237533241);
transform_4(var1, var2, var3, var4, input[12], s41, (u_int)1700485571);
transform_4(var4, var1, var2, var3, input[3], s42, (u_int)2399980690);
transform_4(var3, var4, var1, var2, input[10], s43, (u_int)4293915773);
transform_4(var2, var3, var4, var1, input[1], s44, (u_int)2240044497);
transform_4(var1, var2, var3, var4, input[8], s41, (u_int)1873313359);
transform_4(var4, var1, var2, var3, input[15], s42, (u_int)4264355552);
transform_4(var3, var4, var1, var2, input[6], s43, (u_int)2734768916);
transform_4(var2, var3, var4, var1, input[13], s44, (u_int)1309151649);
transform_4(var1, var2, var3, var4, input[4], s41, (u_int)4149444226);
transform_4(var4, var1, var2, var3, input[11], s42, (u_int)3174756917);
transform_4(var3, var4, var1, var2, input[2], s43, (u_int)718787259);
transform_4(var2, var3, var4, var1, input[9], s44, (u_int)3951481745);
buffer[0] += var1;
buffer[1] += var2;
buffer[2] += var3;
buffer[3] += var4;
}
static void md5_print (struct md5_global_requirements *hash_req)
{
int loop;
printf("[+] MD5 Hash : ");
for (loop = 0; loop < 16; loop++)
{
printf ("%02x", hash_req->hash_digest[loop]);
}
printf("\n");
}
static void string_to_digest (unsigned char *user_string)
{
struct md5_global_requirements hash_req;
unsigned int user_string_len = (unsigned int)strlen(user_string);
md5_initialization(&hash_req);
md5_update(&hash_req, user_string, user_string_len);
md5_hashing(&hash_req);
md5_print(&hash_req);
}
void main(void)
{
unsigned char my_string[150];
printf("[+] MD5 Hash Generator\n");
printf("[+] Programmer : Paulus Gandung Prakosa_ (0x1337day)\n\n");
printf("[+] enter normal text(plaintext) : ");
gets(my_string);
printf("[+] Plaintext : %s\n", my_string);
string_to_digest(my_string);
getch();
}