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Table of contents
Violation of Copyright
Identifiable Parent Property
Frequently Asked Questions
What is copyright?
Is it illegal to copy someone else content?
What are fingerprint bits?
What do we mean by the coalition?
Last Updated: Mar 27, 2024

Identifiable Parent Property

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Ashwin Goyal
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This blog will discuss an essential cryptographic topic, identifiable parent property. Identifiable Parent Property is a concept that comes under Copyright protection. With the identifiable Parent Property, we can trace and identify the culprit responsible for the illegal content publishing.

Identifiable Parent Property

First, let's talk about copyright violation and fingerprinting.

Violation of Copyright

Digital content is what people post on the internet to try to achieve attention or fame through the content they post. But today, it is easy to claim something if you have solid proof of the content.

For example, you can take an example of a music beat. If the producer has copyrighted a musical beat, then only he can claim it belongs to him, or he is the creator of that music. If he does not have proof, anyone on the internet can claim or use it.

Copying is the same thing we need to consider for any digital content. Anyone can copy the digitally available content, claim it as their work, and publish it over the internet. Copyright violation is a crime, and so to ensure clarity for the legal authorities, there is a solution available they can use to trace the rightful owner of the content.

There are algorithms and coding techniques that we can use to enable the tracing of digital content. We will talk about the maths behind these algorithms. But before we talk about the math, we need to know the type of copyright violations.

Pirated Content Distribution

Pirating is an excellent example of illegal content redistribution. When we transmit the content to a network, it is encrypted and but after transmission content will be decrypted, and then it can be easily copied and broadcast over the web.  For example, movie pirating.

This blog will discuss the identifiable parent property used to solve the illegal content redistribution problem. But before we talk about the identifiable parent process, we need to understand the fingerprinting process because IPP (identifiable parent property) process is the inverse of fingerprinting process.

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We can use the fingerprint method to resolve the problem of illegal content redistribution. Suppose there is digital content with n bytes of data; we can avoid illegal content redistribution by adding hidden special bits in the data known as a fingerprint. We can also call this process of identifying confidential data or watermarking.

Let's try to understand fingerprinting with a precise mathematical example. Suppose a content C of X-bits and F fingerprints of size Y-bits; then, we will get D = (C, F). Assuming multiple copies of the content, each with unique fingerprint data D1 = (C,F1), D2 = (C,F2), and so on.

There are two things you should take care of when implementing this technique.

  • First, the fingerprint bits should be well hidden in the data and cannot be easily recognizable by the exploiter.
  • The attacker should not have two copies of different owners because each user will have a unique fingerprint bit and can destroy or erase the fingerprint by comparing both.

With the help of two unique copies, an attacker can create a hybrid fingerprint by comparing the copies and replacing the fingerprint bits with the hybrid fingerprint. Now, whether these hybrid fingerprints can be traced if constructed validly. To answer this, we need to understand the definition of the descendant code.

The set desc(C0) has all the hybrid fingerprints that can be created from the fingerprints in C0; it is known as the descendant code of C0 here desc(C0) consists of all x-tuples f = (f1, . . . , fx ) such that, for all 1 ≤ i ≤ x, there exists a codeword c = (c1, . . . , cx) ∈ C0 such that fi = ci. 

At last, for any c ∈ C0 and f ∈ desc(C0), we claim that c is a parent of f in the code desc(C0).

The w-descendant code of C is denoted as descendant code where w is the number of copies of data and w >=2 consists of the following tuples.

descendant code

All hybrid fingerprints that can be created by attackers of size at most w are included in the w-descendant code.

Identifiable Parent Property

In identifiable parent property, our goal is to determine the attackers who constructed those hybrid fingerprints. We can call this process the inverse of fingerprinting. The main idea behind this process is to determine the coalitions with the help of the tracing methods. 

Let's assume hybrid fingerprints, f ∈  descendant code then suspect coalitions know as the suspect coalitions will be defined as

suspect coalitions

The  suspect coalitions is a set that consists of all coalitions of size at most w that may have created the hybrid fingerprints. Normally  suspect coalitions has only one set, and then we can claim that this subset is responsible for the hybrid fingerprints. There can be possibilities of more than one set in suspect coalitions means there can be more the one group of coalitions. Consider the case where a codeword c ∈ C exists and c ∈ C0 for all C0 ∈  suspect coalitions. Even if we cannot identify the entire guilty subset, any codeword can be identified as guilty.

We can claim that the C is a w-identifiable parent property code if it is for all f ∈ descendant code more in a w-IPP code if 

w-identifiable parent property code

then c is an identifiable parent of f.

Frequently Asked Questions

What is copyright?

Copyright means only the owner who owns a product can make copies of it and publish it.

Is it illegal to copy someone else content?

It is illegal to copy someone else content without their permission and publish it.

What are fingerprint bits?

The hidden bits in the data or content to trace to its rightful owner are known as the fingerprint bits.

What do we mean by the coalition?

A coalition is a group of people to execute or work on a particular subject.


In this blog, we discussed copyright violations and how we can solve them. We have also discussed the fingerprinting method to create a secure copy to trace its rightful owner. The inverse process is the identifiable parent property to identify whether the traced user is valid.

To learn more about cryptography, check out the following articles.


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