Reading assignment: Hashing

Blockchain and Bitcoin 101
#1327

sha256
It’s too hard. You can work backwards through the algorithm but you and your relatives will be dead by then.

#1328

Any input, regardless of size, will hash a 256 bit output when using the SHA 256 function. Keeping in mind the properties outlined in the reading assignment for a cryptographic hash function, if you attempt to use the brute force method to find the original input, in theory you can determine the input.
In reality, one of the following may occur:

  • You obtain the input on your first attempt. You would be extremely lucky if this were to happen.
  • You obtain the input at the very end of all the data. In other words, at the very last possible attempt.
  • You obtain the input anywhere in the middle of the two scenarios described above.
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#1329

My Answers:

  1. SHA- 256
  2. Its hard to brute force because it’s almost impossible to guess and time consuming, Also input and output be the same.
#1330

Basically, you need to brute force the answer, guessing random characters until you get the hash you are looking for.

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#1331

Basically you have 2^256 – 1 different combinations of hashes, and brute forcing this algorithm will take lifetimes!

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#1332

What do you mean by the same?

2 Likes
#1333

What i was trying to say was that each unique input has it’s own output.

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#1334

  1. SHA-256

  2. Because the 256-bit hash is so long, it is infeasible to find an input relating to the output through brute-force. It will take so long that it doesn’t matter.

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#1335

Hi Maoro, then it should be SHA 256, isn´t it?

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#1336

What is the hashing algorithm called used in Bitcoin?

SHA-256

Why is this hashing algorithm really hard (almost impossible) to brute-force?

Because of Pre-image resistance

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#1337

That’s it. Bitcoin uses SHA256 as the hashing algorithm. :smiley:

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#1338

-SHA-256 is the hashing algorithm used in Bitcoin.
-This algorithm is almost impossible to brute force because it is near impossible to find 2 inputs to produce the same output in a hash function.

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#1339

Reading assignment: Hashing

  1. What is the hashing algorithm called used in Bitcoin?

The hashing algorithm used in bitcoin is called SHA-256 (Secure Hashing Algorithm 256). This function in particular can take any string as input and will always produce an output of 256 bits.

  1. Why is this hashing algorithm really hard (almost impossible) to brute-force?

Cryptographic hash functions in general, are not impossible to break (but almost). Any output can be “brute-forced” by guessing the input until you get the same result. This is because they are deterministic. Any input will always create the same output. However, this will take such a long time to do with today’s available technology, that it doesn’t really matter. Small variations in the inputs will create completely different and unique outputs.

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#1340

  1. Sha 256

  2. Sha 256 algorithm is almost impossible to brute force because it is very difficult to find 2 inputs to produce the same output in a hash function.

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#1341

Better answer. Thanks

2 Likes
#1342
  1. SHA256
  2. Brute forcing is infeasible with a 256 hash due to the high number of computational possibilities.
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#1343

1 SHA-256
2) The total number of possibilities is so large that it is unlikely two people get the same result in their whole life time.

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#1344

Hi Maoro. Let me ask a question.How to use a SHA256 in practical life? for instance to word documents or excel sheets? Or e-mail encryption? Is there any guideline on the web?

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#1345

One example are passwords. All modern websites you register to have the password hashed in the database and only those are compared once you try to login.
The reason for this is for security in case the database gets hacked and to prevent developers from knowing what your password actually is. :slight_smile:

4 Likes
#1346

  1. What is the hashing algorithm called used in Bitcoin?
    Bitcoin uses SHA 256 algorithm for hashing.

  2. Why is this hashing algorithm really hard (almost impossible) to brute-force?
    SHA 256 generates hashes that are 256-bit long, and the total number of possible values are 2 to the power 256, which is a 78-digit number. The number of possible values are just too big for a hacker to effective and economically guess a single hash by brute force.

1 Like