SHA hash doesn't match [duplicate]

Can SHA1 be duplicated?

Yes it is possible because of the pigeon hole principle. Most hashes (also sha1) have a fixed output length, while the input is of arbitrary size.

Is sha256 always the same?

A hash function just converts a large amount of information into a smaller random number. It's the SHA-256 algorithm that generates a smaller random number from the large number that was given. But the smaller number will always be the same when the same large number is passed through the hashing function.

Can two files have the same SHA1?

If two files have the same contents then it's probable they will have the same SHA-1 hash value. However, please note that it is possible to create two completely different files that have the same SHA-1 hash value. To be sure you should use SHA-3 or SHA-2 hashing.

Can two different values have the same hash?

A hash collision occurs when a hash algorithm produces the same hash value for two different input values. For instance, a collision would occur in the above example if the hashing algorithm produced a hash value of “01” when a user logged into the computer with the “Pass1234” password or a random value such as “pass.”

Is SHA-1 hash always the same?

SHA1 is a message hashing or digest algorithm where it generates a 160-bit unique value from the input. The size of the input does not matter, because SHA1 always generates a message hash of the same size, which is 160 bits. This may seem very confusing, but the algorithm is just for that.

Can hashes be duplicated?

Indeed it is simply not possible to write duplicate key values into an undamaged hashed file. The hashing algorithm relies upon unique keys, and prohibits duplicates (though it does allow destructive overwrites).

Can two things have the same SHA256 hash?

Almost certainly not. If we were encrypting 256-bit blocks, then yes, they would, because by definition encryption has to be reversible, so encryption algorithms do map things one-to-one. But secure hash algorithms are not designed in this way.

Can 2 files have the same SHA256 hash?

If you have 10^38 files, there is an even chance that two will have the same SHA256. That is more than 10^28 files per person on earth.

Is SHA256 guaranteed to be unique?

Hashes are not unique. This is easy to prove: a SHA256 hash is only 256 bits long, so if you hash all the possible inputs that are 264 bits long, some of them will have to have the same hash because there aren't enough possible hashes for them to all be different. However, for all practical purposes they are unique.

Can SHA-1 be broken?

SHA-1 has been broken since 2004, but it is still used in many security systems; we strongly advise users to remove SHA-1 support to avoid downgrade attacks.”

What is the weakness of SHA-1?

That's because SHA-1 is weak to collision attacks, so an attacker has to be able to produce two messages (which, with current attacks, are of a certain form) that hash to the same value, and it would be hard to do that in an online manner without the assistance of the server.

How common are SHA-1 collisions?

It should take 2^160 operations to find a collision with SHA1, however using the Birthday Paradox, we can have a probability of 50% of finding a SHA1 collision in about 2^80 operations.

What does it mean if hash values do not match?

Verifying a Hash

If the hash values match, the data has not been altered. If the values do not match, the data has been corrupted. For this system to work, the protected hash must be encrypted or kept secret from all untrusted parties.

Can 2 keys have same Hashcode?

1) If two objects are equal (i.e. the equals() method returns true), they must have the same hashcode. 2) If the hashCode() method is called multiple times on the same object, it must return the same result every time. 3) Two different objects can have the same hash code.

Is hash always unique?

A hash of data is always unique. No two distinct data sets are able to produce the same hash. If it does happen, it's called a collision.

Is SHA1 guaranteed unique?

A hash function such as SHA-1 is used to calculate an alphanumeric string that serves as the cryptographic representation of a file or a piece of data. This is called a digest and can serve as a digital signature. It is supposed to be unique and non-reversible.

Is SHA-1 unique?

SHA1 generates an almost-unique 160-bit (20-byte) signature for a text. There is a good description on Wikipedia; see below for the source code. A hash is not 'encryption' – it cannot be decrypted back to the original text (it is a 'one-way' cryptographic function, and is a fixed size for any size of source text).

Can SHA1 be broken?

SHA-1 has been broken since 2004, but it is still used in many security systems; we strongly advise users to remove SHA-1 support to avoid downgrade attacks.”

Is SHA hash reversible?

Irreversible: By design, all hash functions such as the SHA 256 are irreversible.

What is the problem with SHA-1 hash?

What's the problem with SHA-1? The way SHA-1 is supposed to work is no two pieces that run through the process should ever equal the same hash. SHA-1's hash is a 160-bit long—a string of 160 ones and zeros. This means that there are 2160, or 1.4 quindecillion (a number followed by 48 zeros) different combinations.

Does SHA-1 have collisions?

“We note that classical collisions and chosen-prefix collisions do not threaten all usages of SHA-1." There are several potential scenarios in which the new collision could be implemented in an attack, the most likely of which is someone impersonating another user by creating an identical PGP key.

What is the weakness of SHA-1?

Is SHA-2 and SHA256 the same?

If you see “SHA-2,” “SHA-256” or “SHA-256 bit,” those names are referring to the same thing. If you see “SHA-224,” “SHA-384,” or “SHA-512,” those are referring to the alternate bit-lengths of SHA-2.

Is SHA-1 the same result?

Yes it will be. The output of SHA1(x) will always be the same, no matter what OS or what library you use.

Is SHA-1 the same as SHA-256?

(These are sometimes written as SHA-256, SHA-384 and SHA-512. The dash in the middle makes no difference; SHA-512 and SHA512 are the same standard.) SHA2 was designed to replace SHA1, and is considered much more secure. Most companies are using SHA256 now to replace SHA1.

Is SHA-1 no longer secure?

Since 2005, SHA-1 has not been considered secure against well-funded opponents; as of 2010 many organizations have recommended its replacement. NIST formally deprecated use of SHA-1 in 2011 and disallowed its use for digital signatures in 2013, and declared that it should be phased out by 2030.

How fast can SHA-1 be cracked?

Google publicly broke one of the major algorithms in web encryption, called SHA-1. The company's researchers showed that with enough computing power — roughly 110 years of computing from a single GPU for just one of the phases — you can produce a collision, effectively breaking the algorithm.

Can SHA-1 be decrypted?

Absolutely not. SHA-1 (Secure Hash) is a one-way hash function so it's basically impossible to decrypt that String (it's a message digest not a cipher so you shouldn't call that decryption...).