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Table of contents
1.
Introduction
2.
Why there is a need for Authenticated Encryption in Cryptography?
3.
Confidentiality
4.
Integrity
5.
MAC
6.
Frequently Asked Questions
6.1.
What sort of Encryption is used for authentication?
6.2.
Why is trusted Encryption crucial?
6.3.
What type of cryptography is applied during authentication?
6.4.
How can cryptography achieve authentication?
6.5.
What are the four underlying tenets of Encryption?
7.
Conclusion
Last Updated: Mar 27, 2024

Authenticated Encryption in Cryptography

Author Yashi Agarwal
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Introduction

Cryptography is receiving much attention as our lives become more interconnected thanks to the internet. How can we assure security in a world where hackers are clamoring for your emails, passwords, and bank accounts? 

authenticated encryption in cryptography

Today, we'll focus on the two key factors involved: confidentiality and integrity. Using these as a foundation, we will discuss conceptually how authenticated Encryption in Cryptography can ensure both.

Why there is a need for Authenticated Encryption in Cryptography?

The goal of confidentiality is to protect your data. Let's say you email your pal. You want your pal only read the sent email, right? Confidentiality then becomes essential. Maintaining confidentiality is vital so that only the people you intend to get your information can see it.

why it is needed?

Even if your communications are private, they can still be altered. Integrity has a role in this situation. Let's say you email your pal the identical message. Let's assume that the message is intercepted. They are unable to read it because it is confidential. What if they add to it, though? For instance, they add the phrase "I detest you" to the message they forward to you. Never talk to me. Your friend won't be pleased, but your original communication remains private. Making sure the original message is not altered is integrity. If it is changed, the recipient must be informed immediately, or the message will be impossible to read.

Both of these characteristics can be guaranteed by authenticated Encryption in cryptography. While authentication assures integrity, authenticated Encryption in cryptography ensures confidentiality. How are these high levels of guarantee achieved?

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Confidentiality

How can we send a private message? Authenticated Encryption in cryptography function that accepts your key and message as inputs and often passes them through several procedures that mimic randomness is first required. The ciphertext refers to the output that has been encrypted. Although we skip over some other specifics, like using random initialization vectors and working with padding, this is the fundamental flow. 

We say the authenticated Encryption in the cryptography function is secure if an attacker cannot determine the message from the ciphertext with a non-negligible probability. Usually, to do this, two statements are generally taken; one is encrypted, and the other is returned. Which was encrypted is conjectured by the attacker. The attacker should make the right guess 50% of the time because there are only two possibilities. The function is unsafe if the attacker correctly guesses more frequently than 50% of the time with a non-negligible probability.

Fantastic, we've managed to maintain privacy! Nobody can read your message since we have encrypted it. How can we now guarantee integrity?

Integrity

Returning to integrity, let's ensure our friend is aware that our communication hasn't been tampered with. The encryption method is secure. Thus the message cannot be altered. However, several assaults can be made. We'll talk about two popular ones: replay assaults and bit tweaks.

integrity

The recipient receives the ciphertext again in a replay attack. Let's say you pay for your order through an online retailer. A replay attack allows an attacker to repeatedly charge your account by sending your bank the encrypted ciphertext they have obtained. How can you respond to this? A counter can be added, and authenticated Encryption in cryptography can be done along with your message. In this manner, the counter will not match if the message is sent again. The recipient will know that the message is a replay of an earlier one. Thankfully, we were able to stop replay attacks!

MAC

It can be challenging to stop an attacker from changing the ciphertext's bits. Let's say you message someone saying, "Let's meet at 5" Let's meet at six is what your message says after an attacker intercepts it and modifies the last bit. What can we do to fight this? How can we guarantee that your friend understands that your message hasn't been changed?

Message authentication codes (MACs) are helpful in this situation. Separate from the encrypted message, a MAC is calculated. There are three main methods for calculating a MAC:

  • Parallel MAC and Encryption of the original message (e.g., SSH)
     
  • Afterward, MAC encrypts the initial message (e.g., SSL)
     
  • MAC the original message after Encryption (e.g., IPSec)
     

The key with a MAC is that it depends on an external data point, such as a separate key or random initialization vector. With this additional external data point, it is also computed via a series of randomized functions.

This implies that altering the ciphertext will cause the MAC to no longer match. Text cannot be edited since the MAC verifies that the original message has not been changed. The message can no longer be changed. We have prevented an attacker from using two widespread attacks!

Frequently Asked Questions

What sort of Encryption is used for authentication?

Popular Authenticated Encryption modes include Poly1305, CCM, EAX, and GCM. GCM is the default mode used by Ubiq since it is widely used, faster than other modes, and employs the Encrypt-then-MAC strategy.

Why is trusted Encryption crucial?

By doing this, the conversation's confidentiality is guaranteed. When the data the server returns to the client needs to be secure, like a financial statement or test results, Encryption is frequently utilized. Authentication should always be used when you want to know precisely who is accessing or viewing your site.

What type of cryptography is applied during authentication?

The Wide-Mouth Frog algorithm is a technique that uses symmetric cryptography to carry out key exchange and authentication. It employs an arbitrated protocol in which one party sends the trusted third party a message encrypted with the key on its behalf.

How can cryptography achieve authentication?

The user is verified by giving the authentication server their username and a secret key-encrypted challenge message that is generated randomly. In this case, the user is authenticated if the server matches the received encrypted message using its shared private key.

What are the four underlying tenets of Encryption?

Data Integrity, Authentication, Non-repudiation, and Confidentiality are the central tenets of modern cryptography.

Conclusion

In this blog post In this article, we have studied a critical topic in Cryptography, i.e., Authenticated Encryption in Cryptography. We also went over how to build a confidentiality-ensuring encryption function. Additionally, we considered methods for ensuring integrity and thwarting typical threats. We hope this article forms a base for authenticated Encryption in cryptography and helps you to learn more about the same. 

We hope that this article has provided you with the help to enhance your knowledge regarding Authenticated Encryption in Cryptography and if you would like to learn more, check out our articles.

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