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Let's look at the definition in the linked thesis: Definition 2.2.2 (probabilistic one-way function). A probabilistic function, $F$ (with randomness domain $R_n$), with a corresponding deterministic verifier, $V_F$ , is called one-way with respect to a well-spread distribution, $\mathbb{X}$, if for any PPT, $A$: $$\Pr\bigl[x \gets X_n, r \gets R_n, V_F\bigl(...


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Short answer: AEAD is completely the wrong tool for the job. You need a MAC, or perhaps a hash. Here are two important facts about cryptography: Details matter. You can't just take a good, secure construction and modify it and expect it to remain secure. Cryptography is not limited to encryption. from my side because i dont need to decrypt the ciphertext ...


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Your question is unclear and your mathematical expressions are not equivalent. Given a key and a potential ciphertext, is there a corresponding plaintext? In other words, can decryption fail? For authenticated decryption, the answer is an obvious yes: almost all ciphertexts are invalid. You need to know the secret key to produce a valid ciphertext. Without ...


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The problem is that this requires relatively low level access to the cryptographic algorithms. In general the private key can simply be set to a set of bits, although it should actually fit in the field. Setting the highest bit to zero is a dirty trick if the runtime(s) do not accept as many random bits as the key size. This will however let you use any kind ...


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From my understanding of your question, what you want is to hide the name of the file, while enable syncing. You don't actually need encryption per se, since the real name of the file could be encrypted together with the entire file (probabilistically). As such, a potential solution is to just HMAC the file name and use that as the value for syncing. No IV ...


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As I wrote in a comment, the reason your proposed attack does not work is that the random oracle also returns the same result when queried with the same input. The ideal functionality should clearly still be a (random) function, but I agree that the definition in your reference is not as clear as it could be. It would be more precise to say "uniform ...


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