a cryptographic hash function with a 128-bit (16-byte) output, now deprecated

learn more… | top users | synonyms

65
votes
3answers
21k views

How can I create a password that says “SALT ME!” when hashed?

How can I create a password, which when directly hashed (without any salt) with md5 will return a string containing the 8 characters "SALT ME!". The hope is that a naive developer browsing through his ...
53
votes
4answers
116k views

Is SHA1 better than md5 only because it generates a hash of 160 bits?

It is well known that SHA1 is recommended more than md5 for hashing since md5 is practically broken as lot of collisions have been found. With the birthday attack, it is possible to get a collision ...
39
votes
7answers
5k views

Exploiting MD5 vulnerability in this PHP form?

I've been practicing in security-related topics and I came upon this problem which I don't understand at all. You receive a form with one input named pass, and this is the code you need to bypass: &...
36
votes
7answers
32k views

Is MD5 considered insecure?

After all these articles circulating online about md5 exploits, I am considering switching to another hash algorithm. As far as I know it's always been the algorithm of choice among numerous DBAs. Is ...
34
votes
4answers
4k views

Does every hash value have an inverse value?

There are many different hash functions, md5, sha, and others. They take a value V and produce a H via transformation Function(V) = H, where Function is md5, sha, etc. My question is: Does every hash ...
28
votes
3answers
5k views

MD5 collision attacks: are they relevant in password hashing?

DISCLAIMER: This is not an endorsement of MD5 as a password hashing function. I know about parallelization, GPUs, and dedicated password hashing functions like bcrypt and scrypt. With that out of ...
26
votes
2answers
2k views

How can the content of a file refer to its own MD5?

So I just saw this picture on Imgur: http://imgur.com/gxRCrCM The intriguing thing about it is that the picture refers to an old Daft Punk song named "Face 2 Face". The image's MD5 is ...
25
votes
8answers
24k views

Why do people still use/recommend MD5 if it is cracked since 1996?

It's still commonly recommended way of hashing passwords, even if it's insecurity had been proven in 1996 Therefore we suggest that in the future MD5 should no longer be implemented in ...
25
votes
4answers
7k views

Why are MD5 and SHA-1 still used for checksums and certificates if they are called broken?

I was just reading about SSL/TLS stuff, and according to this site (which is rated as A by Qualys SSL Labs), MD5 is totally broken, and SHA-1 is cryptographically weak since 2005. And yet, I noticed ...
15
votes
7answers
5k views

Why does some popular software still use md5?

Nowadays no one dares to defend md5 for any use, and of course they should not! However, much popular software still uses md5 in applications such as password hashing (although it's not simple/plain ...
14
votes
2answers
598 views

Password Salts and Randomness

Alright, so I understand that users are the kind of beasts who like to use one password and make it short and easy to remember (like "doggies"). If I understand correctly, that's one reason we use ...
11
votes
3answers
3k views

Is Postgres password-based authentication secure?

According to Postgres's documentation, Postgres's password authentication method uses MD5 hashing to secure the password: The password-based authentication methods are md5 and password. These ...
10
votes
2answers
14k views

How weak is MD5 as a password hashing function ?

A professor told us today, that MD5 is weak. I understand his chain of thought but pointed out, that IMHO MD5 is a good way to go if you would use a long (even really long) dynamic salts and static ...
10
votes
3answers
9k views

How exactly is MD5 vulnerable to collission attacks?

I've often read that MD5 (among other hashing algorithms) is vulnerable to collisions attacks. I understand the collision part: there exist two (or more) inputs such that MD5 will generate the same ...
9
votes
1answer
2k views

Does bcrypt on top of md5 reduce its security?

A GitHub project I recently checked has a flawed security as they're using an unsalted md5() to hash the passwords. I opened a bug and they acknowledged it. However, the transition from md5() to ...
9
votes
1answer
1k views

Checksums do not match when I download file over http

Just for the test I did the following: Downloaded a page from wikipedia via wget on remote server and named the file test.dat. Then I executed md5sum. I download the file via http and check it back ...
8
votes
2answers
4k views

Truncating the output of SHA256 to 128 bits

suppose we need/prefer 128 bit hash output. for example to generate a 128 bit encryption key or, in other applications (e.g. file integrity verifications), to consume less storage space. i don't know ...
7
votes
3answers
803 views

Is Using MD5 Sufficient Reason to Reject This Payment Processor?

I'm evaluating a credit card processor[1], and I noticed they are using MD5 as part of a salted hash algorithm to protect a secret key. Since I know MD5 is generally considered broken, this feels like ...
7
votes
2answers
164 views

Is there any recommended approach for “upgrading” MD5 hashes to something secure? [duplicate]

I'm currently dealing with a couple of user accounts containing MD5 hashed passwords. These accounts got migrated from an old system into our current system which uses PBKDF2 for password hashing. I ...
7
votes
2answers
2k views

Does the md5 (or any hash for that matter) of a string include the null terminator?

Does the md5 (or any hash for that matter) of a string include the null terminator in its calculations? That is does the hash of a string equal the hash of the sequence of bytes that represents the ...
6
votes
3answers
708 views

Are online hash calculators dangerous?

I was about to use an online MD5 checksum calculator when I realized that my result could be added to a database. This is significant because the string I was going to type in was my bank password. ...
6
votes
3answers
4k views

Using MD5 for file integrity checks?

General Always check the MD5 hashes of the .NET Framework assemblies to prevent the possibility of rootkits in the framework. Altered assemblies are possible and simple to produce. Checking the ...
6
votes
2answers
203 views

Migrating password db off MD5 by chaining MD5 and Bcrypt?

I have a legacy system currently storing unsalted MD5 passwords. Unfortunately, some other controls are not in place (like the ability to expire passwords) and I'm trying to upgrade my algorithm to ...
6
votes
3answers
2k views

NTLMv2 resistance to bruteforcing

I have a question regarding NTLMv2 resistance to password bruteforcing. I know that some modern graphic processors (like Radeon 6990) are able to calculate billions hashes per second and crack NTLM ...
6
votes
1answer
1k views

Replacing weak SSH fingerprint algorithms

Even though MD5 has been broken for years and its vulnerabilities have been used to create real-world rogue X.509 CAs and other horrible things, OpenSSH and PuTTY still use MD5 as the default public ...
5
votes
2answers
613 views

Why not slightly modify an existing hashfunction to create your own? [duplicate]

I read this interesting question on why improvising your own Hash function out of existing hash functions is bad. However this is specifically focusing on 'mixing' existing hashfunctions. What if for ...
5
votes
2answers
1k views

openssl enc uses md5 to hash the password and the salt

Wikipedia states that md5's collision resistance is 2^18 (https://en.wikipedia.org/wiki/MD5). I just found out that openssl enc uses md5 to hash the password and the salt. Let's assume that I want ...
5
votes
2answers
2k views

Do Client Nonces enhance the security of HTTP Digest Auth?

As far as I understand the answer at http://security.stackexchange.com/a/3024/13447, client nonces are meant to prevent attackers from amortizing the costs of brute-force hash computations by being ...
5
votes
2answers
1k views

Code signing with MD5 on Windows 8

I discovered that a signed installer package that is reported as correctly signed on Windows 7 and earlier, is reported as "corrupt" in IE10 on Windows 8. Further investigation showed that the ...
4
votes
2answers
4k views

Why do most hashing functions produce hashes that have characters a-f 0-9?

This is something I never understood about hashing functions. I know that algorithms like whirlpool and blowfish both produce outputs that don't follow this pattern, but why is it that most do? Is ...
4
votes
2answers
4k views

Rounds of MD5 and SHA512 Hashing Algorithms

What is the exact number of rounds employed by the MD5 and SHA512 hashing algorithms? According to various sources, the SHA512 hashing algorithm employs a total of 80 rounds (http://en.wikipedia.org/...
4
votes
1answer
323 views

How fast can a MD5 collision be found

If I have a salt of 16bytes and 16bytes of data, how fast can one find another 16bytes of data so that MD5(salt + data) == MD5(salt + other data)? I don't expect an answer accurate to the nanosecond, ...
4
votes
2answers
2k views

What does GUID have, that a Whirlpool, MD5 or SHA-2 hash don't?

I'm trying to understand the use of GUID and what has always left me wondering is what's so special about them that I should consider using them instead of rolling my own type of unique ID. In other ...
4
votes
3answers
204 views

Can a file have the same MD5SUM but different SHA-1 results from different tools?

I have one file. SHA-1 and MD5 have been generated long time back. I do not know which tool has been earlier. Recently I generated SHA-1 & MD5 for the same JAR. Surprisingly I found that MD5 is ...
4
votes
2answers
1k views

Difference between OS X md5 and gnu md5sum

I have installed the "md5sum" utility on my Mac and there was also a "md5" binary pre-installed in /sbin. My problem and question is this: "Isn't MD5 a standard algorithm?" Because I get different ...
4
votes
2answers
733 views

How safe is to secure sensitive content by URL with MD5 hash and no other authorization?

Suppose we have website that use MD5 hash in URL like this: http://somewebsite.com/XXX/ where XXX is MD5 hash. Content of this website may have sensitive information like transaction details with ...
4
votes
2answers
2k views

Is HTTP Digest + MD5 still an alternative to consume my own api?

I'm reading a lot about implementing security constraints to a REST API. There are a lot of methods, some better than others for 3party applications or to consume my own API. HTTP Basic + TLS (with ...
4
votes
1answer
251 views

X.509 Certificate Signature Collision Vulnerability

Customer complained that during security scan performed on our application the following was raised: 172.22.0.19 - xxxxx - IETF X.509 Certificate Signature Collision Vulnerability - https/tcp/172.22....
4
votes
1answer
782 views

Cracking DES(Unix)/MD5 ARP

This is a basic example of an Unix Pass Encryption. I have a little Hash of MD5 ARP: user50:$apr1$w7YNTrjQ$0/71H7ze5o9/jCnKLt0mj0 user60:$apr1$AIw2h09/$Ti0TRlU9mDpCGm5zg.ZDP. I need to find the ...
4
votes
2answers
2k views

What's the purpose of $LoginKey from the Ashley Madison leak?

According to this site Ashley Madison was keeping an insecure hash stored in their database using MD5, in addition to the far more secure bcrypt hash. This group used the MD5 hashes to quickly crack ...
4
votes
2answers
75 views

Is CHAP authentication still secure?

Assuming the use of the default hashing algorithm MD5, is CHAP authentication still secure? I appreciate that MD5 is considered broken in terms of collision resistance, but I also understand that in ...
4
votes
1answer
134 views

Exploiting MD5/Salt Vulnerability in this PHP form?

I've been practicing security-related subjects and this challenge has befuddled me. Note: I can't access any PHP source code, nor can I edit it. I'm only able to view it. The following is given: I ...
4
votes
1answer
244 views

Why is Windows password security designed this way? [duplicate]

Let's start with the LM hash. The LanMan hash had MONUMENTAL security flaws, like the password being case insensitive (converted to upper), which reduced the keyspace for a brute force attack. On top ...
4
votes
1answer
204 views

What's the weakness of keyed-MD5 for message authentication?

I've seen public web API's using keyed-MD5 to generate message authentication code rather than adopting the HMAC algorithm. People wouldn't just invent HMAC for fun, so it must have some advantages ...
4
votes
1answer
158 views

Is the 64-bits length of the original string padded as well in the MD5 hashfunction?

So, for example I have a string which binary value is exactly 512 - 64 bits long, so the binary conversion of the string does not have to be padded. So that means I have a string of 56 chars. The ...
3
votes
4answers
959 views

Convert SHA-256 to SHA-1 and MD5 - Increase bit length/entropy? [duplicate]

I know this is a real dumb question and I am certainly talking complete rubbish, but let me explain: We have a long SHA-256 hash, e.g.: ...
3
votes
3answers
5k views

Client-side hashing of password before sending it from login form [duplicate]

I have just realized, that my web application is sending unencrypted passwords from login form. It's just like that -- I've analysed, that string sent by user from login form is hashed with MD5 (which ...
3
votes
2answers
5k views

Reversible Hash Function?

Is there any reversible hash function? The hash function like SHA and MD5 are not reversible. I would like to know if there exist some reversible hash functions?
3
votes
2answers
2k views

Program binaries or files with same MD5 hash

I'm looking for 2 different program binaries or 2 different files with the same MD5 hash to prove its weakness and the collisions in the algorithm.
3
votes
1answer
6k views

The brute-force resistence of bcrypt versus MD5 for password hashing?

Can anyone give me an idea? Assume the salt(s) is/are known. For example, if I have a $k$-character long password that is hashed in MD5 versus bcrypt, is there a way to estimate how much more time it ...