edgecase
author: stjohn_piano


Note: This page is subject to change at any time. It is not signed by the author or by Edgecase Datafeed.


Note: All articles published on Edgecase Datafeed are datafeed articles and are signed by Edgecase Datafeed. A datafeed article may contain an article, a signed article, or a checkpoint article. To verify a datafeed article means to check that the GPG digital signature attached to it is mathematically valid and optionally to check its time of publication as measured by block height on the bitcoin blockchain. The most recent articles may not yet have been published on the bitcoin blockchain.


Note: An unsigned article contains no author signature, although it contains the name of the author and is signed by edgecase_datafeed. Authorship of the article is therefore only claimed, not proven. This is useful because someone may only wish to cryptographically sign a limited number of articles, not every article that they ever publish.


1) Install GPG 1.4.x (preferably 1.4.10), if you don't already have it on your system. How to do this is beyond the scope of this recipe.


2) Check that your system has a utility for calculating the SHA256 hash of a file. If it does not, find and install one. How to do this is beyond the scope of this recipe.


3) Browse to the article that you wish to verify. In the Downloads menu, there should be a "Download this article" link to the original datafeed article, which is a text file. Clicking this link should cause your browser to ask you to download this text file.


4) Follow this recipe How to verify a datafeed article to verify the Edgecase Datafeed signature on the article.


5) Open a commandline terminal, change directory to the directory that contains the original datafeed article file, and run the following command to find its SHA256 hash. Replace "sha256" with the appropriate command on your system. Replace "2017-07-12_edgecase_datafeed_article_3_2017-07-12_stjohn_piano_how_i_bought_and_stored_some_bitcoin.txt" with the filename of the datafeed article you are verifying.

$ sha256 2017-07-12_edgecase_datafeed_article_3_2017-07-12_stjohn_piano_how_i_bought_and_stored_some_bitcoin.txt

example output:

7d420e7cd9990a6ed274b0aae0ad22ecd5376d45404ba77c6513bdd7c524eb5e


6) Browse to the article. In the Navigation menu, there should be a link to the next checkpoint in Edgecase Datafeed. Browse to the next checkpoint. Find the article description corresponding to the article. Compare the SHA256 hash in this article description to the SHA256 hash that you generated in the previous step. They should be identical.


7) Follow this recipe How to verify a checkpoint article to confirm that the checkpoint article was published by Edgecase Datafeed at a specific time and has not been changed since that time. Time is measured here as block height on the bitcoin blockchain.


8) Optionally, repeat the previous two steps for the previous checkpoint.


9) You have now confirmed that this article
- was published by Edgecase Datafeed at a time prior to the publication of the next checkpoint.
- (optional) was published by Edgecase Datafeed at a time after the publication of the previous checkpoint.
- has not been changed since the time of its publication.
Time is measured here as block height on the bitcoin blockchain.
An original, unaltered copy of this article is now in your possession.