The last week and a half has been filled with news reports that the blockchain absolutely contains child pornography and illegal content within its records. Is this just old news that has been rehashed, or is this based on something real?
It seems the answer is very cloudy and there is no proof positive answer. The news reports stem from a study that was done called by RWTH Aachen University called A Quantitative Analysis of the Impact of Arbitrary Blockchain Content on Bitcoin.
In their study the make the claim of:
our analysis reveals more than 1600 files on the blockchain, over 99 % of which are texts or images. Among these files there is clearly objectionable content such as links to child pornography, which is distributed to all Bitcoin participants.
The problem, their study may not be all its cracked up to be. Despite the claim that their studied examined the blockchain and revealed 1600 files including links to child pornography as well as one instance of child pornography, they reveal this may not actually be the case.
On page 13 of the 18 page document under a section titled “Illegal and Condemned Content“, they claim to have found “at least” 8 files with sexual content. If they did an accurate study, they should know the exact number of files. So that is seemingly suspicious within an of itself. However we will ignore that and keep reading what they say.
They go on to say of those of those 8 files 5 show, describe, or link to mildly pornographic content. This is again highly suspicious. With only 5 files shouldn’t they properly say “2 described”, “1 showed”, and “2 linked to” mildly pornographic content. If they were doing a true study why wouldn’t they be posting exact numbers and exact figures. Again this seems very suspicious for a study done by a university.
Next they talk about the remaining 3 instances saying they consider the remaining three 3 objectionable for almost all jurisdictions.
Two of them are backups of link lists to child pornography, containing 274 links to websites, 142 of which refer to Tor hidden services.
This means 142 of the links are on the clear web, making all main hub DNS servers guilty of also linking to these websites. Further there have been no reports to police agencies that can be found identifying the specific blocks these can be found in – which is very stange for a college to have done such a study and not turned this kind of evidence over to proper authorities.
Finally they claim:
The remaining instance is an image depicting mild nudity of a young woman. In an online forum this image is claimed to show child pornography, albeit this claim cannot be verified (due to ethical concerns we refrain from providing a citation).
This is very odd indeed. It means that they actually didn’t see the image or if they could, that they could not verify the image was in fact child pornography. Instead they were relying on a single claim of someone posting on a web forum.
For anyone who has ever surfed pornography websites to any real extent, they will know right away these kinds of claims are made all the time. Most of the time, these kind of claims are proven to be false and often the claims are made about famous legal pornography superstars with multiple images and videos all over the place.
In other words, people just look at an image and assume it is illegal because a girl “looks young” without any real evidence that she is a minor, and others come along and prove them wrong by identifying the actress in question.
Again this raises a number of questions. Did they really see the image, and if there was any question about it, why not turn this over to authorities instead of relying on rumors of a web forum? This seems incredibly unprofessional of a university and makes one question the entire study.
Now onto the last piece of information which is perhaps the most damaging to the entire study. On page 5 under a section title “CryptoGraffiti” they state the following:
Several services  insert content via slightly varying P2SH input scripts. They store chunks of a file in P2SH input scripts. To ensure file integrity, the P2SH redeem scripts contain and verify hash values of each chunk. Apertus. This service  allows fragmenting content over multiple transactions using an arbitrary number of P2PKH output scripts. Subsequently, these fragments are referenced in an archive stored on the blockchain, which is used to retrieve and reassemble the fragments.
This effectively means, its entirely possible no single piece of information on the blockchain stores any child pornography at all. Rather that information is broken up across an array of various transactions and one would need special types of software to rebuild all the pieces of data into a single file.
If this is the case, then I can not think of any law anywhere that would say hosting the blockchain could be considered hosting child pornography which has been the claim of all the media outlets.
It seems almost as if they wanted to prove that there is illegal content at all costs.
If we go back to the beginning of the document, the entire reason for this study is actually listed within the abstract.
With our analysis, we thus highlight the importance for future blockchain designs to address the possibility of unintended data insertion and protect blockchain users accordingly.
This is basically saying, they think future blockchains need to be made in such a way that if questionable matterial is found, governments can demand the information be removed, which completely violates why blockchain exists in the first place.
If the blockchain can be changed, altered or have data removed by request, then the blockchain itself becomes useless as it is intended to be immutable. If it is not immutable, then no transactions that take place can be trusted.
Overall no one has ever been able to show evidence of any child pornography being contained within bitcoin blockchain. It seems incredibly more likely, even in this study, that they are proposing hypothetical scenario’s that it is possible to do, despite no one having ever actually done so.
We cannot say for sure there is no child pornography on the blockchain, but then, it also seems the studies equally cannot say for sure there is.