Hashcat is a tool for cracking passwords, but using it on someone else's files is illegal
Hashcat is a command-line program that guesses passwords by running millions of combinations per second. It works by taking a password-protected file — like a RAR archive — and testing thousands or millions of candidate passwords against it until one works. The tool itself is legal to own and study. Using it on files you do not own, or without permission, is a federal crime under the Computer Fraud and Abuse Act.
If you have a RAR file that you encrypted yourself and forgot the password, Hashcat can technically recover it. The process is slow, expensive in computing power, and only works if your password was not extremely long or complex. If you are locked out of someone else's file, or if you are considering this to access data without permission, stop here — that path leads to criminal liability.
This guide explains how Hashcat works, what it actually requires, and the real constraints that make password recovery far harder than movies suggest.
Key Takeaways
- Hashcat works by testing millions of password guesses per second against an encrypted file, but only succeeds if the password is weak or you have a good guess about what it might be.
- Using Hashcat on a file you do not own or without explicit permission is illegal under federal computer fraud law, regardless of your reason.
- Even on your own files, recovery time depends entirely on password length and complexity — a 12-character random password could take years to crack.
- RAR files do not store passwords in a way that makes them straightforward to recover; the encryption is intentionally designed to resist exactly this kind of attack.
- If you forgot your own password, contacting the original creator or checking your password manager is faster and legal.
What Hashcat actually does with encrypted files
Hashcat does not "break" encryption in the way people imagine. It does not find a mathematical flaw or bypass the lock. Instead, it makes guesses. For each guess, it encrypts that candidate password using the same method the RAR file used, then compares the result to the encrypted file. If they match, the password is correct.
This process is called a brute-force attack. Modern GPUs (graphics processors) can test billions of combinations per second, which sounds fast until you realize the actual math. A password with 8 characters from the full keyboard has roughly 645 billion possible combinations. A 12-character password has over 475 quadrillion. Even at a billion guesses per second, a truly random 12-character password would take centuries to crack.
The speed advantage Hashcat has is real, but it only matters if the password is short, uses only common characters, or follows a predictable pattern. If you know the password contains your dog's name and a year, Hashcat can test that specific space quickly. If you know nothing, you are betting on luck or on the password being weak.
Why RAR encryption resists password recovery
RAR files use encryption methods that are deliberately slow to test. When you encrypt a RAR archive, the software applies a key derivation function — a process that intentionally takes time and computing power to convert your password into an encryption key. This slows down every single guess Hashcat makes.
Older RAR versions (RAR3) are faster to attack than newer ones (RAR5), but even RAR3 requires significant computation per guess. A tool testing a password against a RAR file might manage only thousands of guesses per second, not billions. That difference between thousands and billions is the entire reason password recovery is practical for weak passwords but impossible for strong ones.
RAR also does not store the password itself anywhere in the file. There is no "password hint" field that could leak information. The only way to know if a guess is correct is to actually decrypt the file and check whether the contents are readable — a process that takes time and cannot be short-circuited.
The actual requirements to run Hashcat on your own file
If you own the RAR file and want to attempt recovery, you need: the RAR file itself, a computer with a modern GPU (graphics card), Hashcat installed, and a password list or a strategy for generating guesses.
The GPU matters because Hashcat is designed to offload the repetitive work to graphics hardware, which is built for parallel computation. A CPU alone will be thousands of times slower. You can run Hashcat on a CPU, but a single password might take weeks to test.
The password list is where most people start. You can read common password dictionaries online — lists of millions of passwords that people actually use. Hashcat can test every word in a dictionary against your file in hours or days. If your password is in that list, you will find it. If it is not, you are stuck.
Some people use rules — patterns that modify dictionary words. A rule might say "capitalize the first letter and add a number at the end," turning "password" into "Password1", "Password2", and so on. This expands the search space but keeps it finite. If your password is "MyDog2024", a rule-based attack might find it. If your password is a random string, rules will not help.
Why password recovery usually fails in practice
Most password recovery attempts fail because people overestimate how weak their own passwords are. You might think your password is random, but humans are bad at randomness. We avoid certain characters, we use patterns, we repeat ourselves. A password that feels random to you might be in the top million most common passwords.
But if your password is genuinely strong — 12 or more characters, mixed case, numbers, and symbols, with no dictionary words or personal information — no amount of Hashcat will recover it in any reasonable timeframe. You would need to remember it or find it written down somewhere.
The second reason recovery fails is that people do not have the computing power they think they do. A gaming GPU is fast, but it is not fast enough to overcome a truly strong password. Cloud computing services exist that could theoretically rent GPU time, but the cost would exceed the value of almost any personal file.
The legal and ethical line you should not cross
Using Hashcat on a file you do not own, or on a file you own but someone else encrypted and did not give you permission to access, is a federal crime. The Computer Fraud and Abuse Act makes it illegal to "access a computer without authorization or exceed authorized access." Attempting to crack someone else's password, even if you think you have a good reason, crosses that line.
This includes files on shared computers, files belonging to a family member or roommate, files you inherited, or files you think you should have access to. The legal owner or the person who encrypted it has to give you permission, and that permission should be explicit and documented.
If you are locked out of your own file and cannot remember the password, your options are: contact the person who created it and ask for the password, check your password manager or browser history for a saved version, or accept that the file is inaccessible. None of those options involve Hashcat.
Alternatives if you are locked out of your own file
Before you consider any password recovery tool, check whether you have the password saved somewhere. Most people store passwords in a browser, a password manager like Bitwarden or 1Password, a notes app, or an email. Search your email for "password" or the filename. Check your browser's saved passwords (in Settings > Passwords on Chrome or Firefox). Check any password manager you use.
If the file was created by someone else — a colleague, a family member, a vendor — contact them directly and ask for the password. Explain why you need access. They can give you the password or decrypt the file for you.
If the file is truly unrecoverable and you no longer need it, delete it and move on. If you need the data inside, see if you have a backup from before the file was encrypted. If you do not, the file is gone, and that is the consequence of a lost password.
Frequently Asked Questions
Can Hashcat crack a RAR password in minutes or hours?
Only if the password is very weak — fewer than 8 characters, or made from a dictionary word with minor modifications. A genuinely random 10-character password would take weeks or months on a high-end GPU. Anything longer or more complex takes exponentially longer. Most people overestimate how weak their passwords are.
Is it legal to read Hashcat and learn how it works?
Yes. Hashcat itself is legal to own, study, and use on files you own. The illegality comes from using it on someone else's files or files you do not have permission to access. Downloading the tool and reading documentation is not a crime.
What if I forgot the password to my own encrypted file?
Check your password manager, browser history, and email first — most people have the password saved somewhere. If you truly cannot find it, contact whoever created the file and ask them to share the password or provide an unencrypted copy. Hashcat is a last resort and only works if your password was weak.
Does Hashcat work faster on newer or older computers?
It depends on the GPU, not the age of the computer. A newer gaming graphics card will crack passwords much faster than an older one, regardless of when the computer was built. A modern mid-range GPU is faster than a high-end GPU from five years ago. CPU speed matters far less than GPU capability.
What happens if someone uses Hashcat on my encrypted files?
If your password is strong, they will not succeed — it will take too long. If your password is weak, they might crack it. The best defense is a password that is long, random, and not based on dictionary words or personal information. A 12-character password with mixed case, numbers, and symbols is effectively uncrackable with current technology.