So each hash can be generated by 2 different inputs. Also, since the goal ends up right there, it is not about cryptography anymore… rendering any further discussion about your idea off-topic. The storage for the non-reversible could be easily shown that it reaches far beyond the preimage attack. Would it be possible to compress the garbage from a reversible SHA circuit into less than bits, so that [SHA hash plus garbage bits] would be enough to reconstruct the preimage? Sign up using Facebook. This implies that its output is entirely dependent on its input. Feedback post: Moderator review and reinstatement processes. Post as a guest Name. Is it possible for [an algorithm] to compress some bit inputs into strings of less than bits while leaving some strings longer.

summarized the optimization methods for the SHA algorithm in Bitcoin mining What follows are the details: Firstly, the theoretical optimal efficiency of the.

no effort has been made in order to optimise the SHA algorithm specific Keywords: Bitcoin, hash, SHA, mining, ASIC, FPGA, algorithm This thesis was more of a theoretical approach towards studying and optimising SHA for. (accessed. MD5; SHA-1; SHA This Algorithms are initialized in static method called getInstance().

After selecting the algorithm it calculate the digest value and return.

Another way of framing this question: How many bits of information about the preimage are stored in a SHA hash? Writing code in comment? Active 12 months ago. This implies that its output is entirely dependent on its input. This is enough to answer your last question: How many bits of information about the preimage are stored in a SHA hash?

Definition: In Cryptography, SHA is cryptographic hash function which takes input as 20 Bytes and rendered the hash value in hexadecimal number, 40 digits long approx.

This representation is converted into hex format to get the MessageDigest.

1. Hash algorithm is sha algorithm instead of SM3 algorithm. Missiles . [5] Xu W.H., Zhou F. Application of the Theory of Blockchain in Finance[J]. Request PDF | Optimizing SHA in Bitcoin Mining | Bitcoin is a "crypto currency", representation transformations, optimal control and related theories.

[5] summarized the optimization methods for the SHA algorithm in Bitcoin mining.

Modifying SHA itself to optimize the space needed for any kind of without any knowledge of the algorithm, only information theory.

It's output is evenly distributed; that is, every output is equally likely to occur. Since hash algorithms are designed to do the opposite, avalanching small changes in input and making all outputs equally probable, it's unlikely that the "garbage bits" would exhibit any patterns that could be usefully compressed.

Video: Sha256 algorithm optimization theory George Levy - What is a SHA-256 Cryptographic Hash Algorithm?

Asked 1 year ago. Active 12 months ago. If you used reversible gates for every step in a SHA circuit, how many garbage bits would be in the output?

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Thanks for your answer! I wasn't sure if it was zero, or a very tiny fraction. Since hash algorithms are designed to do the opposite, avalanching small changes in input and making all outputs equally probable, it's unlikely that the "garbage bits" would exhibit any patterns that could be usefully compressed. For example, see Would it be possible to generate the original data from a SHA checksum? If you like GeeksforGeeks and would like to contribute, you can also write an article using contribute. I believe your question can be answered without any knowledge of the algorithm, only information theory. |

SHA, the Secure Hash Algorithm with bit digests, is not an encryption al- gorithm, but it is The Coq functional program is a million times slower because it simulates the logical theory of binary integers used Towards optimization. optimization process as it is shown in Fig Figure 1: function analysis for SHA- algorithm, performed.

theoretical results of the proposed design and.

If it boils down to a logic gate Q, what OP asks about has no cryptographic value, purpose, or relation. Home Questions Tags Users Unanswered.

TL;DR: Assuming you do not modify SHA and simply rely on your "metadata" for reconstruction, the size of your "metadata" would be equal to the size of the input. Each of those inputs creates a distinct state of your reversible circuit, so there are 2 such states for each hash output.

Would it be possible to compress the garbage from a reversible SHA circuit into less than bits, so that [SHA hash plus garbage bits] would be enough to reconstruct the preimage?

This representation is converted into hex format to get the MessageDigest. But we can go better by knowing two facts about SHA, which are common to all well-designed hash algorithms:.

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Copying code from Stack Overflow? Video: Sha256 algorithm optimization theory SHA-256 The Center Of Bitcoin - Andreas M. Antonopoulos This in turn answers the original question: how many "metadata" bits would be required for reversibility? Sign up or log in Sign up using Google. |

Basically I just wanted to know how many bits of information about the preimage are preserved in the SHA hash output.

See your article appearing on the GeeksforGeeks main page and help other Geeks. Compression is only useful if it exploits patterns in the input, either because the input space is constrained, or because some inputs are more likely than others.

I would restate the question like this: "Is it possible for a reversible SHA algorithm to compress all bit inputs into strings of less than bits, if of those bits are an SHA hash of the input? If we list all the states for a particular hash output, we can label them all uniquely using bits.

What security goal are you targeting?

Linked 6. I realized that it would be possible to write a reversible SHA algorithm if you stored some additional information as "garbage".