Скачать или смотреть Understanding the Hash Algorithm Used in Digital Signatures

A deep dive into how hash algorithms are determined in digital signatures, their importance, and best practices. Explore the selection of hashing algorithms and their security features.
---
This video is based on the question https://stackoverflow.com/q/62394544/ asked by the user 'KingsNeverDie' ( https://stackoverflow.com/u/7235848/ ) and on the answer https://stackoverflow.com/a/62397774/ provided by the user 'Woodstock' ( https://stackoverflow.com/u/1784011/ ) at 'Stack Overflow' website. Thanks to these great users and Stackexchange community for their contributions.

Visit these links for original content and any more details, such as alternate solutions, latest updates/developments on topic, comments, revision history etc. For example, the original title of the Question was: How Hash Algorithm is determined in Digital Signature?

Also, Content (except music) licensed under CC BY-SA https://meta.stackexchange.com/help/l...
The original Question post is licensed under the 'CC BY-SA 4.0' ( https://creativecommons.org/licenses/... ) license, and the original Answer post is licensed under the 'CC BY-SA 4.0' ( https://creativecommons.org/licenses/... ) license.

If anything seems off to you, please feel free to write me at vlogize [AT] gmail [DOT] com.
---
Understanding the Hash Algorithm Used in Digital Signatures

In the world of digital communications, security is paramount. One of the key components ensuring this security is the digital signature. This technology allows individuals to verify the authenticity and integrity of a message or document. But have you ever wondered how the hash algorithm used in digital signatures is determined? In this guide, we'll break down this critical aspect of digital signatures and explore what makes a hashing algorithm suitable for this purpose.

What Is a Hash Algorithm?

A hash algorithm is a function that transforms input data (known as a message) into a fixed-size string of characters, which is typically a sequence of numbers and letters. This string is known as a message digest. In the context of digital signatures, hash algorithms play a vital role in condensing data to be signed without exposing the complete information.

Why Is Hashing Important in Digital Signatures?

Hashing serves several important functions in the digital signature process:

It reduces the size of the data to be signed, making the process more efficient.

It ensures data integrity, revealing any alterations made after the signature has been applied.

It enables the comparison of signatures to ensure that the original message and the signed message align.

Selecting a Hash Algorithm for Digital Signatures

As we consider how Alice might sign a message to Bob, we arrive at a fundamental question: Which hashing algorithm should she use? Here’s how to approach this choice:

Required Characteristics of Strong Hashing Algorithms

For a hashing algorithm to be deemed suitable for digital signatures, it should be:

Pre-image resistant: It should be computationally infeasible to reverse the hash to obtain the original data.

Second pre-image resistant: It should be unlikely that a different input will produce the same output hash.

Collision resistant: It should be challenging to find two different inputs that produce the same hash output.

Deterministic: The same input should always produce the same hash output.

Fast: It should quickly generate a hash from the input data.

Uniform in output: The output should appear random with an even distribution.

Common Hash Algorithms Used

While Alice has several options, not all hashing algorithms are suitable. Here are some common choices:

SHA3-512: A part of the SHA-3 family that provides a strong level of security.

SHA3-384: A more compact version of SHA3-512, good for scenarios needing less output size.

MD5: Though once popular, it is now considered weak and not ideal for secure applications due to vulnerabilities.

Why Avoid Weak Algorithms?

Older algorithms, such as SHA1 and MD5, should be avoided because they do not sufficiently satisfy the security properties mentioned above. Their weaknesses can expose digital signatures to attacks, making them vulnerable and unreliable.

Conclusion: Finding the Right Document

If you're looking for documentation on the protocols that determine the hashing algorithm to be used, keep in mind that this choice varies significantly from one protocol to another. Most protocols aim to select a hash function known for its strength and resistance to vulnerabilities. You can refer to cryptography standards from organizations such as the National Institute of Standards and Technology (NIST) for more information on recommended practices.

In summary, the determination of a hashing algorithm in digital signatures is a critical decision rooted in security best practices. By selecting robust algorithms, we can ensure the integrity of digital communications and protect sensitive data from unauthorized acc