##project## MD5 analysis... 3.4028236692093846346337460743177e+38 numbers

[jimson]

half of the 16³² is md5 values of another 16^32.

i mean (16^32)/2 md5 values = (16^32)/2 md5 values.
since the pair occupies 2 md5 values.

[jimson]

i don't think there is time for us to run all 16³²
but who know where the "892433944a24f19bb32b34516874a6ff" is located
in the 16^32?
maybe it is in the front part of 16^32.(so we don't spend years to get the result)
ok, this come to another problem,

can we check a md5 chars whether it is in the front, middle or back of series of 16^32?
starting with md5('')?

i know the intended usage of md5 is for message digest
but u see many peeps use it to hash real password and store it in database.
comparing them when user log on.

ok.. just get another thought

if 16³² is the limit, and half of them = md5 of another half of them, then
every pair is basically a knot that tie them together to create a pole of 16³² numbers.
so, it means there is relationship there.(since it is circle like).

buzzLY...

You understand what jimson is talking about.

am i so hard to understand?

anyway, i admit, i preffer if i am 4 years old kid. no bother, no worries...
if everything can start again.

[Weedpacket]

I don't see what you're trying to achieve there. What's so special about the sequence

d41d8cd98f00b204e9800998ecf8427e
74be16979710d4c4e7c6647856088456
acf7ef943fdeb3cbfed8dd0d8f584731
5a8dccb220de5c6775c873ead6ff2e43
76682f743ae018364a082b2e87f2d2f5
0f62265227df1b6d6deec36ab4bc5e76
670df58df5a2ec63b0a33e054418105a
6a0d8f756dfa9c1cd69fed28423ec8ca
628f7643f52b6d6c34accad8a8dc2867
1f16a6c017f12c1539c4947e234de78a
...

That you hope to find

892433944a24f19bb32b34516874a6ff

in it? And what would it prove if you did?

[Weedpacket]

Of course there are periodic sequences - this is inevitable, since every MD5 hash itself has an MD5 hash, and there are only a finite number of MD5 hashes. So? I fail to see (a) where you get this "first half second half" idea from, (b), what's so special about the sequence you're generating that makes it easier to search (and search for what?) than just starting with 00000000000000000000000000000000, and then going on to 00000000000000000000000000000001, 00000000000000000000000000000002, ... (that's easier to search: look there's 892433944a24f19bb32b34516874a6ff! Right after 892433944a24f19bb32b34516874a6fe!)
and (c) what this has to do with finding passwords.

[Weedpacket]

If you were going to look for passwords, a more suitable sequence of generated md5's would be

d41d8cd98f00b204e9800998ecf8427e
93b885adfe0da089cdf634904fd59f71
55a54008ad1ba589aa210d2629c1df41
9e688c58a5487b8eaf69c9e1005ad0bf
8666683506aacd900bbd5a74ac4edf68
ec7f7e7bb43742ce868145f71d37b53c
8bb6c17838643f9691cc6a4de6c51709
06eca1b437c7904cc3ce6546c8110110
89e74e640b8c46257a29de0616794d5d
e2ba905bf306f46faca223d3cb20e2cf
5e732a1878be2342dbfeff5fe3ca5aa3
...

Along with of course strings that hash to them.

[jimson]

i got another thought... thanks God...

okay,
let say
md5('1') = c4ca4238a0b923820dcc509a6f75849b
md5('01') = 96a3be3cf272e017046d1b2674a52bd3
md5('001') = dc5c7986daef50c1e02ab09b442ee34f
...
md5('00000000000000000000000000000001') = e629f196dc612509ea9a61df552423a0

so, just only 1 number can generated 32 md5 numbers.
decrease to 31 when reaching 10

16 ^ 1 = 16
16 ^ 2 = 256
16 ^ 3 = 4096
16 ^ 4 = 65536
16 ^ 5 = 1048576
16 ^ 6 = 16777216
16 ^ 7 = 268435456
16 ^ 8 = 4294967296
16 ^ 9 = 68719476736
16 ^ 10 = 1099511627776
16 ^ 11 = 17592186044416
16 ^ 12 = 2.8147497671066E+014
16 ^ 13 = 4.5035996273705E+015
16 ^ 14 = 7.2057594037928E+016
16 ^ 15 = 1.1529215046068E+018
16 ^ 16 = 1.844674407371E+019
16 ^ 17 = 2.9514790517935E+020
16 ^ 18 = 4.7223664828696E+021
16 ^ 19 = 7.5557863725914E+022
16 ^ 20 = 1.2089258196146E+024
16 ^ 21 = 1.9342813113834E+025
16 ^ 22 = 3.0948500982135E+026
16 ^ 23 = 4.9517601571415E+027
16 ^ 24 = 7.9228162514264E+028
16 ^ 25 = 1.2676506002282E+030
16 ^ 26 = 2.0282409603652E+031
16 ^ 27 = 3.2451855365843E+032
16 ^ 28 = 5.1922968585348E+033
16 ^ 29 = 8.3076749736557E+034
16 ^ 30 = 1.3292279957849E+036
16 ^ 31 = 2.1267647932559E+037
16 ^ 32 = 3.4028236692094E+038

the limit is 16^32,
so, the total from 16¹ to 16³¹ = 3.62967858049E+038
which is obviously larger than 16³² limitation.
and we just use only hex values which is 16 chars only.

okay, right now, i got one question...

WHO HAVE ALREADY FOUND THE FIRST CLASH VALUE.

which means who are the person who have 2 strings or more which can generate the same md5 hash ?

if u got info, please post here.

the first half, second half idea is... i thought
if we just concentrate on the checksum that contained
16 chars first half is = c4ca4238a0b92382
so we need to find what numbers that generated
the 16¹⁶ pairs<=second half. // maybe this thought fail to stand.

[BuzzLY]

jimson, I apologize -- I did not mean to offend you with my post. The way you word things, I find difficult to understand -- perhaps because of your translation from your language to English. I did not mean any disrespect.

And the comment about 4 year olds was not meant to insinuate that YOU were 4 -- only that Weedpacket sometimes seems to have the patience of Job, and would probably spend forever answering a 4-year-old's questions.

Hope that clears things up -- I did not mean any disrespect to you. You seem like a VERY intelligent person -- probably way beyond my intellect! My comments to Weedpacket were intended as a compliment to you.

[goldbug]

Am I the only one that finds it extremely silly to create/run a brute-force style method using PHP (or any other "scripting" language)??

[Mordecai]

Originally posted by jimson
hi, can u please give me a summary what ur crack() function will do...

Umm, look at the code. It tests passwords against another password.

I built an addon (basically just added md5()) to test 1200 words against and MD5'd word.

[jimson]

Buzzly, thank u...
looks like i have to study english... grammar or vocabulary ?
for the VERY intelligent person... well, i dare not take it.
i know only little very little. anyway... goldbug just prove that i am silly... 🙂

Am I the only one that finds it extremely silly to create/run a brute-force style method using PHP (or any other "scripting" language)??

actually, the reason i use php is just to present the concept, if i gonna run for a long-long time, then i will fireup the VB or C, C++ and do some small app to make it runs.
and we are talking about the 16³² numbers... extremely huge
what i know is, we can't run all of them.

since, i believe there is some kinda relationship between each md5 checksum value (increment of 1h, 0x31 0 to 0x31 1), i am thinking a way to predict a range where possible 32 chars will generate the specified md5 checksum.

[stolzyboy]

looks like i have to study english... grammar or vocabulary ?

personally from reading some of your posts, i think the grammar work is needed more often than not, since it sounds like you are literally translating, and more often that not, it makes you sound somewhat like Yoda

Understand me, you do?

[goldbug]

Originally posted by stolzyboy
Understand me, u do?

Edited to match existing standards. 🙂

[jimson]

maybe i should write a book,
How to code in Jimson's Grammar... 🙂

lukily ur guys point me out...

stol, who is Yoda... <= is it creature? in the stars wars

[stolzyboy]

yep that is yoda

[Weedpacket]

Originally posted by jimson
WHO HAVE ALREADY FOUND THE FIRST CLASH VALUE.

No one, yet. But there are fewer strings with fewer than 32 hex characters than there are strings with exactly 32 hex characters, so there is no guarantee there that a clash would be found in the first 31 characters.

Of course, the strings being hashed ought to span the whole character set ASCII 0 - ASCII 255, not just 0-9a-f.

How to code in Jimson's Grammar...

See? He does know how to use capital letters!

[jimson]

513,980 kb

large.. but he is cool...
anyway, i am 170+ cm...

[jimson]

modercai... ur bot must be able to check grammar. especially my grammar...

first person to produce 2 string that have same hash will be insert into Book of world record... 🙂 how about that..🙂

[jstarkey]

Sorry, I haven't read the whole thread, but for MD5 cracking:

http://www.phpbuilder.com/columns/tim20000505.php3

See the comments.

[jimson]

i just read almost all the messages..
this one worth visit : http://membres.lycos.fr/mdcrack/nsindex2.html

MD5 is a one way hash algorithm providing a final 128 bits length hash whatever was the original text length. The resulting hash is often used to sign a document thus giving a way to certify that the original content wasn't altered neither by a software/hardware error nor by a third party.
Today many applications (most of them are network oriented) use MD5 for authentication purpose avoiding any plain text password on the wire.
In such a case, clients typically send a password hash over the network to the server wich in turn, make its own client password hash to compare the two hashes. If they match together, the server considere the client know the good password and the authentication process is ended althought the server may be totaly wrong! MD5 can not theoricaly be reversed that is to say nobody can guess the original text from its hash (even with little strings like passwords) but since the number of resulting hash is fixed (2^128), many strings will give the same hash.
Surveys about the predictibility of such collisions have never, till now, prooved that somebody could arbitrary choose another text giving the same MD5 signature.
In the worse case, a third party may change the original text with something that has no signification at all and the well known birthday attack is easily defeated with some few precautions. Nevertheless if a random collision is not really a problem for a letter that needs to get sense, it may be a valuable threat for a MD5 based password authentication scheme.

Now, imagine that an innocent user A authenticate himself sending his hash on the wire to the server B while being sniffed by an attacker X who easily catch the hash.
X, in most cases, doesn't only want the hash but need an original plain text password.
He doesn't actually need the same password but any collision that can be typed from the client (At least one char). If chances are few for A password to own a collision in the first hashes generation, the probability is not null and X will still be able to bruteforce the original password during hours/day/weeks.
In some cases, B will first give A a "somewhat randomly" generated string to harden the hash generation but if this technic will protect against replay style attack, it won't change anything against bruteforce since randomize strings are clearly sent over the network. By the way, X will generate clear passwords accordingly with the right randomizing scheme.

This password attack is the purpose of MDcrack, it will bring you back any found MD5 collision in the range previously defined (default is 1-8) giving you a good idea of your password hash strongness. Because MD5 will always give the same result for a given input, you can easily precompute every hashes of a fixed password length to do further effective collision searches.
Dictionnary attack/clustering modes will give others possibly reliable way to crack passwords hashes. This matter is really serious since nowadays a lot of web based application are using this authentication protocol, exposing customers to a complete identity robbery.

The problem is not at all in the MD5 algorithm in itself but in the manner application are using it. MD5 was not defined for authentication purpose and give no real security against data compromision.

[jimson]

md5 crack analysis

total md5 checksum hash = 16³² = 3.4028236692093846346337460743177e+38
from the statement, 4,560,830 md5 brute force attempts per second on a 1.2Ghz athlon
(God forbid they actually have a 2.4)....
so, (16^32)/4560830 = 74609745796475304596613907431711 seconds to run all md5 checksum
74609745796475304596613907431711 / 60 seconds
= 1243495763274588409943565123862 minutes / 60
= 20724929387909806832392752065 hours / 24
= 863538724496241951349698003 days / 365
= 2365859519167786168081365 years. // still a big years... 🙁 only God knows where am i by then...

so, one day, the cracker can run
1 minute = 273649800
1 hour = 16418988000
1 day = 394055712000

x
--- * (16³²⁾ = 394055712000
100

= 1.1580256584131357235533153747888e-25 %
or
= 0.0000000000000000000000001158025658413135723553315374888 %
oh God... only God knows.

but...
if we can target the possible range of the resulted hash.. then maybe we can work faster.
well, i need coffee... and cigarettes..