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Comment by blueflow | Hacker News Reader

... in the same sense that ROT13 or base64 would be a cipher.

Rot 13 is a cipher. It's a substitution cipher, and more specifically a shift cypher or Caesar cipher. It's not a secure cipher but it is one.

Base64 is an encoding. It's an algorithm, no attempt at secrecy, thus not a cipher.

And what do you think is the algorithm from the article? Looks awfully similar to base64 to me, except its lacking the bit-shifts. Both use a lookup table like that.

I think a lot of this depends on if you read the article as the scream cipher being specifically the exact listed substitutions or just any substitution with forms of As. Also depends on how you define encoding, cipher and the overlaps between the two. Plus questions on the relevance of intent, transformation of data, plus changing of meaning and definitions over the years. Some people say morse code is a cipher, but braille isn't - definitions can depend on way more than the black and white logical "but it does this" you're using.

You'd do better debating this with a real life friend over a pint, rather than wasting your time trying to argue with multiple people here.

And thus we arrive at SCREAM64 encoding, base64 in scream cipher.

Sweet Lord Jesus.

such a great idea that we ought to call it based64 encoding

If you use base64 with the intention of hiding the encoded information, surely it’s as much a cipher as rot13 is, right?

The original Caesar cipher supposedly also had a constant offset, yet it's still considered a cipher.

A bad substitution cipher is still a cipher. Just one you shouldn't use for anything important.

Yes https://en.m.wikipedia.org/wiki/Substitution_cipher

First sentence:

> with the help of a key

So, where is the key?

The key is the data table, representing which each character encodes to or from.

In the code in this article, the key is the mapping stored in ‘CIPHER’.

First, second, and third statements of the provided source code.

Like i said, by these measurements, base64 would also be a cipher.

And people are telling you yes, they (rot13 and base64) are indeed ciphers. What's the confusion?

What people in this thread call a "key" is, not like a key, auxiliary input data, but hard-coded into the program. We are looking at encodings.

Maybe this differentiation is not popular or well accepted, but it was surely part of my cryptography curriculum and the following exam. I'd rather believe my prof than strangers on the internet.

Key can mean different things in different contexts. In a substitution cipher, the key is the mapping. In modern ciphers, the key would be some set of secret bytes. Everyone agrees that this cipher would be a bad way to encrypt/encode something. But using the word cipher like this has real historical meaning, and that is the meaning that is being used in the project.

Ha ha ha ha ha ha! You want the key?

https://www.youtube.com/watch?v=vsb9-wPYpxI

… and no, since neither the enciphering nor the deciphering do a 1:1 mapping for all possible input code points.

That's not a requirement. Pigpen is a substitution cipher.

You will find that the pigpen cipher has a 1:1 mapping between its input alphabet and its output alphabet, and that a 1:1 mapping is a necessity for full invertibility.

Ăặȧạaǎẩậā ȧẫạ13, áaǡặ64, aẩắ ạẵǎǡ ẩặả ǡăȧặaầ ăǎäẵặȧ aȧặ aậậ ǎẩǡặăȁȧặ, áȁạ ạẵặā ắẫ ầặặạ ạẵặ ạặăẵẩǎăaậ ắặằǎẩǎạǎẫẩ ẫằ a ăǎäẵặȧ.

Yog-Sothoth has heard your plea, and will be along to help you shortly.

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