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Table of contents
Key in cryptography
Broadcast encryption 
Tracing Illegally Redistributed Keys
Frequently Asked Questions
Is encrypted information secure?
Is it possible to hack encrypted data?
What is the major drawback of data encryption?
What exactly would be a key distribution concern?
Why is piracy a problem?
Last Updated: Mar 27, 2024

Tracing Illegally Redistributed Keys

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Privacy is a significant worry for everyone in today's environment. In today’s world, messages you transmit are encoded into ciphertext before being transferred across the communication channel. When the other person receives it, it is decrypted to reveal the message you wrote. A cryptosystem is a system that performs this process. In this blog, we will discuss how tracing illegally redistributed keys is processed. We will also be discussing broadcast encryption. Let's get started.

Tracing Illegally Redistributed Keys

Key in cryptography

A key is generally a string of characters used in cryptography to change data so that it seems random. It encrypts data like a physical key, so only someone with the appropriate key can unlock or decrypt it.

Plaintext + key = ciphertext

Plaintext + key = ciphertext

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Broadcast encryption 

Broadcast encryption is used in one-way communication systems to allow two unknown parties to exchange a cryptographic key to protect shared data. 

The primary objective was for a leading broadcast site to be able to broadcast secure communications to an arbitrary group of receivers while reducing key management transfers.

  • Suppose we use the naive method of giving each client device its key and sending an individually encrypted message to all valid client devices. 
  • In that case, we will need a very long transmission, i.e., the number of legitimate devices multiplied by the length of the message. 
  • On the other hand, if we divide legitimate devices into groups and provide each valid device with all of the keys corresponding to the group to which it belongs, each legitimate device must keep many keys.
Broadcast encryption
  • This method is used to deliver encrypted content, like paid TV shows, over a broadcast channel so that only subscribers who have paid their subscription fees can decrypt the content. 
  • The difficulty stems from the necessity that the eligible users' list varies with each broadcast emission. 
  • Hence, revocation of individual users or user groups should be achievable only via broadcast transmissions, with no impact on any remaining users.
  • Broadcast encryption spreads key information that lets qualified users rebuild the content-encryption key rather than directly encrypting the material for qualified users. 
  • In contrast, revoked users need more information to recover the key. 
  • The usual setup under consideration is a unidirectional broadcaster with stateless users, which is very problematic. 
  • In contrast, multicast encryption refers to a scenario in which users are provided with a bi-directional communication link with the broadcaster and, therefore, may more easily preserve their status, and where users are not only dynamically revoked but also added. 

Amos Fiat and Moni Naor explicitly examined the subject of practical broadcast encryption for the first time in 1994.

Tracing Illegally Redistributed Keys

Each decoder box has a unique set of keys. Assume that a group of evil users collaborates to develop a pirate decoder by appropriately mixing keys across their decoder boxes. Because a pirate decoder can decrypt signals, it's possible that it can be sold on the black market. 

  • Each decoder box's set of keys may be regarded as a codeword in a particular code, and the keys in such a pirate decoder could be considered ciphertext within w-descendant code (somewhere in the DOM tree that is nested within it). 
  • If the code fulfills the w-IPP code (establish safeguards against the unauthorized production of copyrighted digital data )property, it is traceable. ​​

A pirate decoder may then be traced to at least any member of such a coalition that developed it. As a result, when a pirate decoder is seized, at least any of the individuals involved can be identified.

Assume an authorized user is suspicious of unlawfully replicating his decoder and now is under vigilance. Whenever the pirate decoder is discovered, it may be checked to see if it matches the user ID. Now, tracing illegally redistributed keys is easy.


  • First, the alleged traitor's identity is converted into a string δID = f(ID). δID is fed into the pirated decoder alongside a valid ciphertext c. 
  • If this decoder correctly decrypts c, the suspicious user is recognized as the traitor. 
  • To track out the traitor, you must understand the derivation function f. If f is made public, anybody may determine if a given decoder corresponds with any identifier ID. Otherwise, only authorized parties have access to the tracing capabilities.
  • The security of such a traitor tracking technique is determined by how secure its decryption key d is divided. 
  • The basic algebraic structure may perform splitting operations with varying features with most public-key cryptosystems.

Frequently Asked Questions

Is encrypted information secure?

Almost. Encryption protects your online privacy by converting personal information into communications only intended for the people that require them - and no one else.

Is it possible to hack encrypted data?

Yes, encrypted data may be hacked.

What is the major drawback of data encryption?

Encrypted data, like human passwords, is simple to crack.

What exactly would be a key distribution concern?

The main issue with employing cryptography is distributing keys only to organizations that require them and not to others.

Why is piracy a problem?

Piracy is the act of copying digital content or software without the consent of the originator. Here the original content is duplicated, shared, and traded, allowing non-privileged users to download or view it.


This article incorporates information about Tracing Illegally Redistributed Keys and explains broadcast encryption.

If you think this blog has helped you enhance your knowledge and you want to explore cryptography more, check out our articles:

  1. Cryptosystem
  2. What Do You Mean by Cryptosystem?
  3. Cryptography
  4. Public Key Cryptography
  5. Monte Carlo Simulation


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