Specific to the security of passwords: hashing, entropy, cracking, resets, lockouts, etc.

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16
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2answers
4k views

What's wrong with storing private keys in the cloud?

I know this sounds like a dumb question, but whats wrong with it? Assuming that all private data is encrypted (by the client) using PBE AES256, then is this scheme more vulerable than storing keys on ...
6
votes
2answers
1k views

Is it better to hash n*x times in sha1 or n times in sha512 on the client side?

I already know I"m going to hash the user's password n times in either sha512 or n*x in sha1 before it is sent to the server. Once at the server, I'm going to use bcrypt set to use ~1/100th of a ...
7
votes
2answers
8k views

Help understanding basic user authentication with salts and hashing

I for some reason am not understanding how to execute a secure authentication between client and server for a user. I've read many resources, and I understand how to use the hashing and salting tools, ...
4
votes
4answers
2k views

SMS Authentication: random OTP or a cryptographic one

I'm adding two-factor authentication using SMS to enhance an existing login process. Since I'm not working with physical tokens, I was wondering what is considered the safest: Sending random 8 ...
7
votes
2answers
444 views

PKCS#5 Salt privacy? [duplicate]

Possible Duplicate: Password Hashing add salt + pepper or is salt enough? In the official documentation of the PKCS5 V2.0 standard, we can read "The salt can be viewed as an index into a large ...
11
votes
2answers
1k views

Requiring regular password change but storing previous paswords?

My bank requires me to change my password regularly but then they can detect if my password was used before. They probably store the old password (possibly hashed) in order to detect it. I think this ...
4
votes
2answers
189 views

Did I miss anything when checking for passwords?

I was provided with a "challenge" forensics image of 2MB in size (floppy); they provide the disk image and want you to uncover as many passwords as you can find. I downloaded the image and dd'd it to ...
3
votes
1answer
462 views

How strong are google's Application-specific passwords? [duplicate]

Possible Duplicate: Google Account: implications of using application-specific passwords In 2-step verification of google accounts, we need to use the Application-specific passwords generated ...
0
votes
1answer
140 views

What is a preferred method of security-conscious creation of login cookies [duplicate]

Possible Duplicate: Is it safe to store the password hash in a cookie and use it for “remember-me” login? I am working on a webapp that uses localStorage alone (http://...
3
votes
1answer
144 views

Password hashing on a load balancing setup

I've been doing some research into password hashing implementations and would like to know if it's feasible to have two servers hash passwords to the same database? I've come across the Bcrypt.net ...
22
votes
6answers
2k views

Hash function change

I have user account passwords stored in a database using an unsafe (old) cryptographic hash function. What is the best/usual approach to changing password hash function? Only two ideas come to my ...
16
votes
5answers
1k views

Is it legal to log passwords from failed logins?

Is it legal to store/log mistyped passwords? How many of you have seen this happen in a log file or DB?
6
votes
1answer
615 views

Should password hashes be encrypted or HMACed?

Assume I am hashing user passwords with PBKDF2, bcrypt, scrypt, or some other secure key derivation function. Are there: tangible security benefits, precedents, and respected research for ...
19
votes
7answers
944 views

Are common passwords at particular risk?

The question Should we disallow common passwords like “password” and “12345”? on User Experience immediately made me think that these common passwords were extremely dangerous not because they are ...
4
votes
2answers
397 views

How to prove a password guessing theory from Matt Bishop's book “Introduction to Computer Security”

First, this is not a homework problem. This is a problem from Matt Bishop's book "Introduction to Computer Security" which was used as one of the textbooks for a Computer Security class I took last ...
2
votes
3answers
147 views

How to make an outbound request to users to update their passwords?

Clearly it works best if the request to update a password happens as a response to an inbound request to access a known system, but how do you make an outbound request to users to update their ...
2
votes
1answer
15k views

Why it does not matter whether you type HEX or ASCII as WEP WiFi password?

I know that I can pass password in HEX as a keyphrase to WiFi network using WEP encryption as well as ASCII. But somehow you cannot get the ASCII when you only know HEX value. Can anyone explain the ...
2
votes
0answers
97 views

How can a service shorten a password if it is not stored in plaintext? [duplicate]

Possible Duplicate: How can Microsoft validate a shorter password on Microsoft accounts (MSDN)? My Microsoft password was 18 characters long and when I updated to Outlook.com it started to ask ...
6
votes
3answers
637 views

How can Microsoft validate a shorter password on Microsoft accounts (MSDN)?

I recently ran across this when logging into MSDN. (I saw this screen after typing my initial credentials.) I have a 20+ digit password, however there's apparently a new requirement for Microsoft ...
2
votes
1answer
211 views

IKEv2 in remote access scenarios

Can someone explain why, in remote access scenarios, IKEv2 EAP password-based user auth combined with IKEv2 PUBKEY gateway auth is preferable over mixed IKEv2 PSK/PUBKEY auth using the same password ...
2
votes
2answers
163 views

Bad planning causing weak passwords

The athletic department at my university has a facebook page and on it they said "the first 500 people to register for this event will get free t-shirts". When registering one has to create an account ...
3
votes
1answer
1k views

Why do some large companies still store passwords in plain text/decrypt-able format? [closed]

In the last couple of weeks I've come across two fairly large companies who seem to not have stringent password security: Tesco - they store passwords in an "encrypted" format, yet they can decrypt ...
8
votes
4answers
1k views

Is storing answers to security questions in plain text bad form?

If the input for the security question is completely digital, should the answer to a security question be hashed (or at least encrypted) on the authentication server?
6
votes
6answers
4k views

Does having a minimum number of digits improve password security?

Some password systems will enforce at least X of a type of character - a common one I see is 'minimum 3 numeric characters'. As far as I understand, simply allowing certain character classes, like ...
12
votes
3answers
4k views

How can I prevent someone from accessing a Windows XP system via boot disk?

Apparently a computer system protected by a a login password, e.g. Windows XP, can be easily hacked by someone with physical access to it using methods like this one: http://www.raymond.cc/blog/...
2
votes
6answers
765 views

Why does the password field not show the entered text?

Why does the password field not show the entered text? When we enter password it shows ... or '*'. What are the security advantages of this?
0
votes
1answer
206 views

How can I prevent my son accessing my PC? [duplicate]

Possible Duplicate: How can I prevent my kids from bypassing my computer restrictions based on Windows Vista? My 14 year-old son is using a Ctrl+Alt+Del procedure to get into my computer even ...
4
votes
3answers
678 views

How can I determine whether a website somehow protects against brute force attacks on my password? (assume I can't create an anonymous account)

After the hack of Mat Honan I studied my own laundry list of accounts I have at the numerous web sites I use. There is one fact that stands out: Many of the websites severely restrict the size and ...
15
votes
2answers
2k views

Are there some good papers (or discussions) on using Markov chains or Hidden Markov Models for password auditing/cracking?

As a programmer and language enthusiast I've been very interested in Markov chains for some time. Considering the influence of natural language on password and passphrase selection (by humans of ...
4
votes
4answers
1k views

Can public keys be a security risk when performing password-less SSH logins?

Some companies use monitoring software such as nagios or icinga. In order to perform checks on the servers, they often need password-less SSH logins. The servers being checked put the public key of ...
5
votes
3answers
449 views

Are there any regulations against financial companies storing passwords in plaintext?

A bank that I use stores my password in cleartext or perhaps using reverisible encryption, which is just as bad. I know this because when you click "Forgot your password?" (or similar) link, it ...
1
vote
1answer
630 views

Securely tell the user his password in new WHM/Cpanel account creation?

I understand it's not safe to send passwords via email but when accounts are created via WHM/Cpanel, I have to let the user know what password I created for them. How can I relay the password safely?
1
vote
3answers
438 views

Logic for generating Strong Password?

I try to encrypt password using MD5 but there are decoders for MD5. So I'm worried about encryption of password for big website. Is there any logical suggestion or step function to generate strong ...
2
votes
1answer
678 views

How can passwords be stolen from Yahoo?

I always understood that servers don't actually store user passwords. Instead, they store hashes of passwords and then they validate the user input by applying the hash function, then compare the ...
4
votes
4answers
568 views

Is there any explanation (other than storing plaintext) for case-insensitive passwords?

I've come across a few organisations stating that passwords are case-insensitive. Obviously this is ridiculous, and a gigantic red flag from a security point of view. Is there any explanation for why ...
5
votes
7answers
3k views

What is the best way to securely keep clear passwords?

I'm working on a web project that will connect to a database. For that, I will have to store the login/password of that database user in clear (encrypted in a symmetrical way) in order to be able to ...
9
votes
1answer
1k views

Bcrypt as a key derivation function?

I read a lot of entries at stack exchange about bcrypt and why it is supposed to be better than PBKDF2 in terms of password storage. I'm asking now if bcrypt is better than PBKDF2 in terms of key ...
33
votes
7answers
13k views

How can crackers reconstruct 200k salted password hashes so fast?

I'm researching for a small talk about websecurity and I found one article about the formspring hack, which made me curious. They claim to have used SHA-256 + salt We were able to immediately fix ...
4
votes
4answers
555 views

Is it secure to use similar password over different accounts?

I have a strong password which is a long, unfamiliar word phrase. I would like make other account use a password with similar level of complexity but I don't like to remember so many password over ...
1
vote
2answers
434 views

Seeking advice on how to build a box to brute force hashes? [closed]

I work in a startup security firm, and I need to build a GPU-based to brute force password/hashes, which can be used to validate password strength and test hashing algorithms. I expect some high ...
3
votes
3answers
300 views

When changing a password, does it have to be completely different?

When changing a password how important is it to have a significantly different one? For example is it bad to reverse the sequencing of the old password to make a new one or change a few numbers?
1
vote
2answers
177 views

is it appropriate to set restrictions on a user's password? [duplicate]

Possible Duplicate: XKCD #936: Short complex password, or long dictionary passphrase? Im developing a website and am curious as to the current trends in the nature of passwords. Is it good to ...
5
votes
3answers
749 views

Trying to understand password hashing

I am trying to get a grasp of password hashing. Back in the days it seemed so simple, just MD5(password + salt) and you are done. Then md5 was proven to have collisions so people started moving to ...
2
votes
4answers
547 views

If the attacker knows part of the password but not the length, does that help him in any way?

The idea behind this is that if knowing part of the password and not the length is useless, "passwords" can be easily stored in cleartext or paper since you would just add your own n characters ...
0
votes
0answers
244 views

What is the most secure way to recover password online? [duplicate]

Possible Duplicate: Can anyone provide references for implementing web application self password reset mechanisms properly? I have website which sends generated password to any person who ...
28
votes
4answers
7k views

Why is using salt more secure?

Storing the hash of users' passwords, e.g. in a database, is insecure since human passwords are vulnerable to dictionary attacks. Everyone suggests that this is mitigated via the use of salts, but the ...
40
votes
7answers
3k views

“Real” Salt and “Fake” Salt

During a Q&A period at DEFCON this year, one member of the audience mentioned that we're using "fake salt" when concatenating a random value and a password before hashing. He defined "real salt" ...
9
votes
1answer
1k views

Would it make sense to use Bcrypt and PBKDF2 together?

I've read various opinions about whether Bcrypt or PDBKF2 is a better key derivation hashing method. The answer seems to depend on a lot of complicated factors that are not easy to analyze. Would ...
15
votes
3answers
2k views

What is a good enough salt for a SaltedHash?

Since I'm hashing all passwords with each their own salt, is there a benefit to the salt being really random, or would an incremental counter or a guid be good enough? Also, is there a benefit of ...
0
votes
1answer
668 views

website hacked and all its content erased despite the protections

i was hacked by a guy who erased everything. I spent the day to put everything in order, and i would like to find a solution for this : he erased all the files, and also changed the title for "www" in ...