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Comment by netsharc | Hacker News Reader

Good knowledge, now explain why it's like that.

{" is ASCII 01111011, 00100010

Base64 takes 3 bytes x 8 bits = 24 bits, groups that 24 bit-sequence into four parts of 6 bits each, and then converts each to a number between 0-63. If there aren't enough bits (we only have 2 bytes = 16 bits, we need 18 bits), pad them with 0. Of course in reality the last 2 bits would be taken from the 3rd character of the JSON string, which is variable.

The first 6 bits are 011110, which in decimal is 30.

The second 6 bits are 110010, which in decimal is 50.

The last 4 bits are 0010. Pad it with 00 and you get 001000, which is 8.

Using an encoding table (https://base64.guru/learn/base64-characters), 30 is e, 50 is y and 8 is I. There's your "ey".

Funny how CS people are so incurious now, this blog post touches the surface but didn't get into the explanation.

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That’s really a leap about the writer’s interest.

They could just as easily have felt the underlying reason was so obvious it wasn’t worth mentioning.

I know how base64 encoding works but had never noticed the pattern the author pointed out. As soon as read it, I ubderstood why. It didn’t occur to me that the author should have explained it at a deeper level.

Is it? In the first paragraph the author clearly shows his ignorance of base64. When told that it "looks like base64 encoded JSON" he

    was incredulous but gave it a go, and it worked!!

Even if you don't notice the ey specifically the string itself just screams base64 encoding, regardless of what's actually inside.

TBC I was addressing the parents suggestion that the writer was incurious.

One blog post is hardly enough to just someone as ignorant but after quick look at the author's writing/coding/job history, I doubt he is that either.

I think it's fantastic that you can look at a string and feel it's base64 essence come through without a decoder. Thinking about it for a minute, I suspect I could train myself to do the same. If someone who already knew how to do it well wrote a how-to, I bet it would hit the front page and inspire many people, just like this article did.

I just don't get the urge to dump on the original author for sharing a new-to-him insight.

They were probably expecting base64 encoded binary data. Base64-encoded-binary-inside-Base64-encoded-JSON-inside-JSON is a really strange construction if you haven't encountered it before, because of how much space it's wasting playing a game of Russian nesting dolls.

Just add a layer of compression periodically to reclaim the wasted space and it will all work out.

If you have a compression that works on encrypted data, you can avoid wasting your time on the "encryption".

Base64 isn't encryption. The overhead added follows an extremely predictable pattern. That said I've no idea what the performance of common compression algorithms might be in such a use case. The comment was entirely tongue in cheek.

I apologise for my mistake. Either the comment got edited or I misread encryption somewhere in there.

I think the audience already understands why it works, it's more the knowing there's a relatively small set of mnemonics for these things that's interesting. "eyJ" for JSON, "LS0" for dashes (PEM encoding), "MII" for the DER payload inside a PEM, and so on.

I've been doing this a long time but until today the only one I'd noticed was "MII".

The audience yes, but the author clearly seems to not understand it when they wrote this the first time.

> I did a few tests in my terminal, and he was right!

He clearly had no clue how base64 worked. You don’t need a test, if you know it.

> As pointed out by gnabgib and athorax on Hacker News, this actually detects the leading dashes of the PEM format

They needed help for this. I’m not sure that they opened Wikipedia at last to understand how base64 works even now. The whole article has an “it’s magic!” vibe.

I'd be very hesitant to consider this as some runaway symbol of "CS people being incurious now" over the author simply not being this deeply invested in this at the time of writing in the context of their discovery, especially since it almost certainly doesn't actually matter for them beyond the pattern existing, if even that does.

> it almost certainly doesn't actually matter for them beyond the pattern existing, if even that does.

https://web.cs.ucdavis.edu/~rogaway/classes/188/materials/th...

And there goes my limit of curiosity now regarding this. I'm interested in what you have to say, but not 25 page mini-novel PDF from someone else interested. I'm glad you enjoyed that piece, but I have no interest in reading it, nor do I think it's reasonable for you to expect me to be interested. Much like with the author and the specifics of this encoding.

Wow, that's an amazing story. I'd never read anything by E. M. Forster before, and I certainly wasn't expecting 1920s sci-fi like that.

The author also doesn't explain what JSON is. Because it's obvious to the target audience. There's simply no explanation necessary

I think CS grads often skip the part of how something actually works and are happy with abstractions.

CS post covid is in the worst state it has ever been, vibe coding and AI has enabled a category of grifters beyond the wet dreams of blockchain hacks.

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