With public key cryptography, why can't someone decrypt a message using the public key?

OmegaMouse@pawb.social to

No Stupid Questions@lemmy.world · 7 months ago

I’ve been trying to get my head around this and I’ve watched a few videos but they don’t seem to specifically answer my question.

According to what I’ve found online, messages encrypted with a public key can only be decrypted with a private key. But in practice, how is that possible?

Surely a public key contains a set of instructions, and anyone could just run those instructions in reverse to decrypt a message? If everything you need to encrypt a message is stored within a public key, then how is it a one-way process?

It’s likely that I’m misunderstanding a core element of this!

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