That SEO slop article is simply wrong on the math of cryptography, and relies on an example of the one time pad not being used only one time. Either way, the interesting thing about the OTP is that you cannot prove that any particular plaintext exists, so the nonsense about trying to infer any particular plaintext from the encrypted text. Frequency analysis doesn't help when there is no correlation between different bits of the key, the same way that flipping a fair coin 10 times reveals nothing about what it will likely be on the 11th flip.

40 and 56 bit encryption keys are obsolete as they are now easily broken. 128, 192, and 256 are the standard now. 512 bit encryption is being played around with.

You might be tricked into believing that a 512 bit key is twice as hard to crack as a 256 bit key. No, a 257 bit key is twice as hard to crack, and a 512 but key is 2^256 (1.5 x 10^77 ) times harder to crack. So if you can crack a 256 bit key in 1 second, a 512 bit key would take 3,672,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000 years to crack using that same technique. Or, if you can crack 1 million 256-bit keys in a second, go ahead and take 6 zeroes off the number I just listed.

Throw in developments in quantum computing

Good luck with that. Quantum computers aren't anywhere close, and more importantly, have nothing to do with AI.

AI isn't going to make cryptography obsolete.