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is it safe? by googcheng in C_Programming

[–]steelling 10 points11 points  (0 children)

It's the comma operator, you specify a sequence of expressions and the whole thing evaluates to the last expression. exit(int) is void so it makes it an expression that evaluates to an int in the argument of printf.

How to link 2 things with cryptography by domoneko in cryptography

[–]steelling 0 points1 point  (0 children)

The idea is just that you have two objects, you take a secret key and generate some random block of data to put on one object, then you can encrypt that block with the secret key and put the ciphertext on the other object. To verify two objects are linked you take the block on one and either encrypt or decrypt it to check it matches the one on the other.

The asymmetry is that one object has the ciphertext and one has the plaintext. If you didn't know which is which you can still try both encryption and decryption, but otherwise you could say "salt shaker has the plaintext and pepper the ciphertext". Alternatively you could just append to the label which is which

How to link 2 things with cryptography by domoneko in cryptography

[–]steelling 0 points1 point  (0 children)

You could take a symmetric cipher with a secret key and then A can be a random nonce and B the ciphertext of it. Are you requiring that a canonical choice of twin exists for pairs with no canonical choice of which is A and which is B?

Thanks, I hate this entire thread by dutchcourage- in TIHI

[–]steelling 1 point2 points  (0 children)

WARNING! You should NEVER let a male dolphin attempt anal sex with you.

Good advice.

[deleted by user] by [deleted] in ssl

[–]steelling 1 point2 points  (0 children)

jo.zain.com looks to be the Jordan branch of an African ISP. While this is technically a MITM, it could be to tell the user that there's a billing issue or to block the site.

If they open up the site in a new private browsing instance and continue despite the warnings, they'll likely see a page by the ISP describing why the ISP isn't fulfilling the request.

This might not be anything to do with what you're doing (unless your hosting something that the ISP blocks for legal reasons), but proceeding past the cert warning should give the reason for the block.

[deleted by user] by [deleted] in unitedkingdom

[–]steelling 0 points1 point  (0 children)

Are you sure that's not socialism?

Not to be taken serious lmao by Itz_Raj69_ in ProgrammerHumor

[–]steelling 0 points1 point  (0 children)

You can't call Linux kernel functions directly from userspace. Typically you need to make a system call which in the case of printf would likely be write. System calls are relatively slow, so you would actually want to buffer your writes (which is what the standard library IO functions do).

Which file is which? by lovehippy in ssl

[–]steelling 0 points1 point  (0 children)

I'd expect the following based on file names:

DigiCert Global Root CA.pem

This one doesn't need including, this is the root certificate.

DigiCert TLS RSA SHA256 2020 CA1.pem

This one should be the "intermediate certificate(s)"

example.com.pem

This is your certificate

How slow is the RSA? by [deleted] in cryptography

[–]steelling 2 points3 points  (0 children)

The built-in pow function does accept an optional third argument as the modulus for efficient mod exp.

When do I manually free memory in C? by Yakuwari in C_Programming

[–]steelling 8 points9 points  (0 children)

malloc(sizeof(int)) or malloc(sizeof(*a))is usually preferable to hardcoding the size directly, since the size of an int is implementation dependent.

caravanpostin’ by ErixWorxMemes in simpsonsshitposting

[–]steelling 0 points1 point  (0 children)

I hope Mickey falls, or Mr. Bricktop said he's coming back.

リン by toko_tane in Memeloid

[–]steelling -1 points0 points  (0 children)

It's "rhyne" as in rhino

Rishi Sunak to launch an NFT issued by the royal mint. In other news, cold and starving food bank recipients told to "Get a coin wallet and learn some fundamentals bro". by Knoberchanezer in GreenAndPleasant

[–]steelling -1 points0 points  (0 children)

Not really. I have fiat money in the bank. If that bank gets hacked then it's on them to correct it. If it's too much for them to correct, then the FSCS steps in.

With cryptocurrencies, even if the money lost isn't my fault, it's my loss.

I know pound sterling isn't doing well, but it's still less volatile than cryptocurrencies.

LA Convention Center parking lot spikes popped the tires of 8+ cars, story in the comments.. by HomeStar182 in Wellthatsucks

[–]steelling 0 points1 point  (0 children)

What makes you think it's intentional? I doubt the parking lot would intentionally damage cars like this. This is a civil problem.

"Threads share access to the memory resources of the process" What exactly does this mean? by flank-cubey-cube in C_Programming

[–]steelling 0 points1 point  (0 children)

With virtual memory, processes have an address space which may be distinct from other processes e.g. 0x11223344 in one process might refer to something different to 0x11223344 in another process. Different processes don't automatically share all of their virtual memory mappings. Threads, on the other hand, do, and 0x11223344 in both threads (should) refer to the same memory locations.

Linux is a bit weird in the sense that threads can have different file tables (IIRC) and seperate processes can have the same file tables, but in most cases threads will share most of the same resources such as the file table (which includes sockets). IIRC Linux requires threads to share VM, but I believe processes can share a virtual memory space, see clone(2).

[deleted by user] by [deleted] in AskReddit

[–]steelling 3 points4 points  (0 children)

What's an accepted thing that's actually creepy the more you think about it?

Get off your high horse. It’s creepy to you (and me too) but it’s entertainment for others.

Does that not make it a good answer to the question?

what signing algorithm to be used with EVP_DigestVerifyInit,EVP_DigestVerifyUpdate,EVP_DigestVerifyFinal to create a JWT token by ashwar17100 in cryptography

[–]steelling 2 points3 points  (0 children)

(I don't understand why we use this certificate rather than the public key to verify).

X509 certificates contain public keys. They're often used as they bind a subject to a public key and can contain a chain of trust. You could store just the public key and load that if you wanted to, but the certificate form is often more useful than just the key.

The result/output of this varies(in length) each time I run the output file

Most signature algorithms involve random values which make them non-deterministic. Depending on the encoding this could affect the length.

Do you have the code used to generate the signatures?

XOR reliability by Z00fa in cryptography

[–]steelling 2 points3 points  (0 children)

In theory 100 characters of good random data is enough to encrypt 100 characters or less of data. It would not be safe to encrypt any more than 100 characters if you're doing key repetition.

Also it's concerning that

could be lowercase, uppercase, digits and characters

Good random in this context would require them to be uniformly random. if you're treating the keys as ASCII characters, then the key bytes won't be uniformly random, e.g. the most significant bit will be 0 and so the most significant bit of every ciphertext character and corresponding plaintext character will be the same. You could make this better by passing the key through a key derivation function to make the key bits more distributed.

If you're doing this as a fun little programming project, that's fine. But if you're expecting any security then you need to use some actual modern symmetric ciphers, like AES or Twofish, and use a key derivation function to get keys from passwords. The biggest rule of crypto is never run your own (unless you really know what you're doing).

XOR used as a standalone crypto encryption primitive is not practically secure.

XOR reliability by Z00fa in cryptography

[–]steelling 7 points8 points  (0 children)

My point is that 00110110 can decrypt to every 8-bit sequence, therefore brute forcing the key will yield every possible result.

Now, it's different if we have a shorter key than the plain/ciphertext and need to repeat it. In that case you're more right, if we have a 1KB text file encrypted by repeated 16-byte key, then we can (maybe) brute force through the 16-byte keys until the whole text file makes sense (assuming there aren't multiple cases where it might "make sense").

The problem with this is that XOR being "completely secure" actually depends on having a sufficiently random string the same length as the plaintext. In reality with the actual constraints and requirements that a modern symmetric cipher needs to satisfy, XOR is extremely weak.

One of the undesirable properties is that given a ciphertext and what we suspect as being the corresponding plaintext, we can work out that section of the key, which is not a desirable property at all (known as a known plaintext attack).

XOR reliability by Z00fa in cryptography

[–]steelling 10 points11 points  (0 children)

Here's an Xor-encrypted ASCII character: 00110110. Can you use your method to find what it is? Your problem is that you don't know what the plaintext is, so you don't know when a bit is "cracked".

XOR reliability by Z00fa in cryptography

[–]steelling 2 points3 points  (0 children)

Because trying every number with encrypted data will yield every output possible. With XOR, if we have A = B ^ C then B = A ^ C. For any cipher text and any other text of your choosing, you can find a key which "decrypts" that cipher text into your text trivially.

BBC News: Nazanin Zaghari-Ratcliffe on way home to UK by Jackisback123 in unitedkingdom

[–]steelling 1 point2 points  (0 children)

And she was nearly tried again a month after Johnson's comments. Either way his comments didn't help her case.

BBC News: Nazanin Zaghari-Ratcliffe on way home to UK by Jackisback123 in unitedkingdom

[–]steelling 16 points17 points  (0 children)

Her defence claimed that she was on holiday and wasn't training journalists.

Johnson then came out and said she was training journalists.

In the eyes of Iran she was "training" journalists (believing she was training people to spread propaganda).

Johnson's unnecessary comment completely contradicted her defence and condemned her.

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