This is the final essay for lecture two (the Byzantine Generals Problem) of the University of Nicosia MOOC, Intro to Digital Currencies. This prompt asked students to describe a centralized asset or transaction ledger and describe advantages or disadvantages of decentralizing the ledger. I must admit, I might have stretched a bit in my example selection. Nonetheless, I’m proud of this one and I think the analogy is interesting and useful, if unlikely or a bit silly. This and all the essays are all tagged: Digital Currency Course Essay Series.
Prompt: Describe a centralized asset or transaction ledger and describe what advantages or disadvantages might exist if it were to be implemented in a decentralized form.
This might be a little out there, but I have to admit I peeked at the everyone else’s responses to avoid picking a popular example of a centralized ledger. The example of a centralized asset ledger I’ve selected is YouTube.com’s database of available videos. Currently, to add an asset to the ledger, a YouTube user must first create or sign in to an existing account with Google. The user uploads the video to YouTube’s servers, and software updates the database with information about the video, such as what account submitted the video, a timestamp, whether the video is marked public (searchable and all may view), private (only viewable by accounts specified by the uploader), or unlisted (not searchable but anyone with the link may view), among other data. Assets may be removed from the ledger by several methods: YouTube staff will delete videos that violate its terms of service or as a result of a successful Copyright Infringement Notification, and the user who submitted a video may also mark it for deletion. Once the deletion is effected, the video may no longer be viewed nor the deletion reversed; however, the YouTube Terms of Service, section 6C, state, “you understand and agree, however, that YouTube may retain, but not display, distribute, or perform, server copies of your videos that have been removed or deleted”, so the content may still exist on the YouTube servers.
In a decentralized model of the database of YouTube videos, users might post content to a self- or decentrally-owned site and submit a link to a blockchain-like ledger of submitted videos. The blockchain software might visit the link to validate that a video exists and trace prior confirmed submissions to ensure the same link is not already included in the ledger. The uploading user may also be required to prove that she has the ability to manage the linked content.
There are several advantages and disadvantages that might arise by converting YouTube’s database of video submissions to the decentralized model described above. Firstly, with a decentralized ledger, it would be impossible to remove the initial link submission, as the ledger must be public and prior additions unalterable in order to function and foster trust in the system. A user could remove or change the content from the linked site; however, the entry of the link in the ledger would still persist in the history of asset additions. This feature has advantages, for example, it would be the individual users’ responsibility to comply with copyright law as opposed to leaving this right in the hands of the central managing authority (i.e. Google). One could also imagine scenarios where the inability to truly remove record of the link could be disadvantageous, such as if the content is viral and politically unpopular. Taking the maintenance of the ledger out of a single entity’s hands does have clear advantages in that searching for content could be vastly improved, and there is no risk that the central manager fraudulently alters data relating to the video, such as timestamp or the submitting user. Furthermore, data about uploaded videos would be visible to all instead of trusted to a single entity, and with multiple nodes maintaining full copies of the ledger, a denial of service attack on the database would be exponentially more difficult.
Although unorthodox, a decentralized asset ledger of uploaded video content might prove advantageous over the centralized model employed by Google’s YouTube.com.
References:
1. YouTube.com, Video Privacy Settings
https://support.google.com/youtube/answer/157177?hl=en
2. YouTube.com, Terms of Service
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