-1
votes
1answer
100 views

Is there a benefit to encrypting a file multiple times? [duplicate]

If I had to store a text file with some confidential information on the cloud, would encrypting the file multiple times (say, 3) with different passwords using WinRAR (AES with a 256 bit key) provide ...
2
votes
1answer
119 views

Given a hash, salt, charset and password length, how do you get the password without brute-forcing it?

I got that question on an exercise and I'm not sure what to answer. Without conventional brute-forcing and without a rainbow table, how could I find out the password? An improved brute-force ...
0
votes
1answer
42 views

Does restarting an encrypted session increase security and deter attacks?

When a user initiates a SSH connection for example, keys are exchanged and a session is established with a new "passphrase" each time. If an attacker were to attempt to brute force this connection, ...
0
votes
1answer
58 views

Is encryption less resistant to brute-forcing compared to hashing?

I understand that a hashing algorithm like bcrypt uses several rounds of hashing to make it computationally expensive for a brute-force attack. How does encryption work against a brute-force attack? I ...
1
vote
2answers
163 views

How do you know if blowfish key is correct?

Encryption novice here so maybe this question makes no sense... Obviously if you know what the clear text is and it decrypts right, you have it. But if someone is running through keys to break the ...
1
vote
1answer
134 views

What is the strength of the key derivation function on Android device encryption?

What is is strength of the key derivation? Specifically, how many milliseconds or microseconds would it take a desktop computer to check a guessed password to see if it is a match? I am aware this ...
4
votes
3answers
200 views

Is there any reason in particular encryption keys aren't arbitrarily large?

It's my understanding that the more bits an encryption key has, the longer it takes to break the encryption. What is the down side of having a larger encryption key or why don't we see keys of size ...
0
votes
1answer
137 views

How can brute force scripts tell once they're found the correct key?

If you have a random block of data and you encrypt it with a key, how can a brute force script tell when it has found the correct key? Is it possible without some sort of reference to the original ...
2
votes
2answers
3k views

How do you bruteforce decrypt data if you don't know what you are looking for?

If I wanted to brute-force decrypt data, I would try decrypting it with a key and see if the decryption returned nonsense. If the decryption returned meaningful data (ex. something that a natural ...
-2
votes
2answers
1k views

Can the U.S. goverment crack encryption? [closed]

Does USA government have the sufficient processing power to crack keys in matter of seconds? Let say 2048-bit RSA, for example. Since the RSA algorithm was developed by USA government (NSA?), I ...
0
votes
0answers
31 views

How can I determine the encryption used by knowing input and result? [duplicate]

Is it possible to determine the encryption or hash used if I know the original input and final output? There is a similar post here: Determine encoding/hashing methods used based on knowing the input ...
2
votes
1answer
3k views

How long it will take to crack a RAR password?

I wonder how long it will take to crack 16 character alphanumeric WinRAR password for a mini supercomputer. As far as I know graphic cards are preferred over CPUs to crack passwords nowadays. If we ...
2
votes
2answers
209 views

Slow down symetric encryption

I'm developing a program in Java. In one step data should be encrypted and exported in a file. As of now we are encrypting in AES-256 I want to slow down a possible brute force attack as much as ...
6
votes
3answers
294 views

How much added security do I really get with a longer key size?

Imagine I have a cipher which supports keys of 128, 192 or 256 bits. Suppose that there are no vulnerabilities in the cipher regardless of key length. I'm going to use it to encrypt something, and ...
3
votes
2answers
17k views

Remove Password Protection from XLS Document

Similar to what is listed here, http://datapigtechnologies.com/blog/index.php/hack-into-a-protected-excel-2007-or-2010-workbook/, is there a way to remove the password from an XLS (Excel 2003) ...
1
vote
2answers
437 views

Hash, encryption of file… key? Need help [closed]

So my previous question was with some help on pcap files as I am doing a security course and we have a challenge to figure out what was going on in our network. Now one of the files I retrieved is an ...
2
votes
2answers
2k views

how long does it take to brute force varying encryption standards?

Let's say I want to encrypt information in a database. What would be the best encryption algorithm to use and why. I was thinking AES, since it's widely used as a government standard, but if the ...
2
votes
1answer
2k views

Brute-force a passphrase, generated by `pwgen 16 -s`, of a GPG CAST5 archive

A sad story: One of our hard drives failed. While it was failing, we managed to take a quick backup. As it is our standard practice, we encrypted the backup using GPG (by however method Duplicity uses ...
3
votes
2answers
585 views

Can key files be brute-forced like passwords?

Let's say you use a program like Truecrypt or Keepass which allows you to have a password + key file. I understand that passwords can be brute-forced/dictionary-attacked but is the same true for key ...
5
votes
3answers
2k views

What are the odds of brute-forcing an archive with 256-bit encryption?

I have a file (a stand-alone archive). I lost the password to it, but it has been encrypted using 256-bit encryption. The password is some 20-odd characters long (including non-alphanumeric ...
7
votes
3answers
627 views

It is possible that brute force attempts are successful before the worst case, correct?

When I read about a password being secure and stating that it would take X amount of week, years, etc. isn't that referring to the worst case? What happens if the brute force method is successul in ...
30
votes
2answers
35k views

How to estimate the time needed to crack RSA encryption?

How to estimate the time needed to crack RSA encryption? I mean the time needed to crack Rsa encryption with key length of 1024, 2048, 3072, 4096, 5120, 6144, 5120, 7168, 8192, 9216, 10240, 11264, ...
3
votes
3answers
374 views

How to optimize compressed file cracking?

I'm currently doing research on cracking encrypted, compressed files (specifically: uif, zip, 7z, dmg). Looking at all the utilities out there, it seems the time it takes to crack something is ...