CODEWITHSUNDEEP
javaencryptioncryptographysha1
Alex Dowining
Alex Dowining

Reputation: 970

Java using SHA1

I try to implement a SHA1 decoder but i can't find something usefull on internet. Can anyone help me find information on how I can implement an SHA1 decryption. I want to transform the encrypted data to Strings.

Upvotes: 0

Views: 1638

Answers (4)

Marinos An
Marinos An

Reputation: 10818

If you need to find the password behind a SHA1 hash, put the Hash on google. If the password is common, and the hash is not 'SALTED', you have a chance to get the password.

Else read this: https://en.wikipedia.org/wiki/Rainbow_table

Upvotes: 0

CodesInChaos
CodesInChaos

Reputation: 108790

Hash functions are designed to be one-way. So you can't simply calculate the input from the output. Doing this is called a pre-image attack. If the message itself can't be guessed, such an attack requires around 2^159 attempts, which is infeasible.

The best way to reverse SHA-1 is to guess the input. For typical user passwords this attack succeeds quite often, since the password isn't complex enough. For example a typical GPU will be able to try >100mio passwords per second.

This is why we don't use plain SHA-1 for password hashing. We use deliberately slow schemes, such as PBKDF2, bcrypt or scrypt with sufficient work-factor.

Upvotes: 0

Frank Visaggio
Frank Visaggio

Reputation: 3718

If you figure out how to crack sha1 props to you. I think the government may be able to do it but you would be hard pressed to find a public library that has a smart algorithm that doesnt take a great deal of resources to crack.

they claim they can crack it and decrypt it, I doubt it works another source that claims they can decrypt it, i doubt their code is publicly available though

Is there a specific reason you are trying to decrypt it, maybe there is a flaw in your design or another way to solve your problem?

heres a neat diaolog about the progression of sha1

Upvotes: 1

Jon Skeet
Jon Skeet

Reputation: 1499760

I try to implement a SHA1 decoder but i can't find something useful on internet.

SHA-1 is a hash function. It's one-way: you hash the data, and get a hash. If you hash the same data, you'll get the hash; if you hash different data, you'll "almost certainly" get a different hash.

If you could "decrypt" it, it wouldn't be doing its job.

Upvotes: 9

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