On the security of OAEP

liavz123

7/16/24, 10:32 PM

I saw theorems stating that RSA-OAEP (or the similar variant OAEP+) is CCA-secure in the random oracle model.

I wonder about the following:

Is RSA-OAEP (or even OAEP+) CPA-secure in the plain model? If so, what properties does the hash functions need to hold?
Are there any lower bounds for the padding length compared to the plaintext? I remember hearing that one needs to have at least $\Theta(n)$ bits of padding to argue security.
Are there any upper bounds for the plaintext length compared to the modulus (when using a single exponentiation)?

0 + 1

padding

oaep

Maarten Bodewes

7/16/24, 10:51 PM

You can simply put dollar signs around your $\LaTeX$ to get it formatted (SE allows MathJAX on specific sites such as cryptography). Double dollar signs will center a formula and put whitespace around it. No need for all the niceties / fluff, we'll take upvotes, accepts and good responses instead :)

Elon Musk

I sit in a Tesla and translated this thread with Ai:

EN: On the security of OAEP

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