# Tag Info

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The closest notion used in the literature seems to be “proof / argument of knowledge” (PoK / AoK). See [GMR, BG] as well as Wikipedia for its definition. Indeed, giving out the key would be a proof of knowledge (but it's not of much interest to cryptography). The part about “not sending the value to the other party” seems to be related to zero-knowledge (ZK)....

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Solution: N parties have N private keys. One party generates a new private key called the master private key, and it encrypts that for each of the other parties. The other parties store that encrypted payload. Each one can verifies that the public matches the private, and can sign that verification. A new master key can be rolled at any time, if, for ...

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Yes, and Key-Encryption Keys often are symmetric. When they are, they do not bring the benefits of asymmetric cryptography; in particular, anyone with the KEK and passively eavesdropped ciphertext can decrypt the distributed keys. That does not make use of symmetric KEK pointless: KEK would typically be distributed, stored and used with more precautions (...

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The question's formula $\text{Dec}(k_i,\text{Enc}(K_i,p))=p$ is for both encryption and decryption. Encryption is $p\mapsto\text{Enc}(K_i,p)=c$. Decryption is $c\mapsto\text{Dec}(k_i,c)=p$. Note that $\text{Dec}$ can be a true function, but $\text{Enc}$ likely has a hidden random argument. Otherwise encryption would be deterministic, and deterministic ...

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Since the private key belongs to person $i$ only they can perform the decryption. It will turn out signature, hey, wait there. This expression is commonly used to express the RSA operations public key encryption and decryption, digital signatures, and verification of the digital signature. This created the confusion that still remains over the net and even ...

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The "public address" is not a standard cryptographic notion (except perhaps in some subfield like cryptocurrency), and no context is given. That makes the most sensible way to rephrase the question: Can a public key be found from its SHA-256 or RIPEMD-160 hash? No, for any public-key cryptosystem, and absent other information (e.g. a list of ...

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What you need to do is find some document that associates you with the virtual or hardware wallet. The most obvious way is the receipt you used to purchase the physical wallet. If you didn't keep the receipt, the company you bought it from may be willing and able to help you.

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The answer of @poncho was not an exact solution to my question so as StackExchange rules suggest I add my answer it might be helpful to someone. We construct attacker as follow. Attacker gives $m_0 = 0$ and $m_1$ which have been chosen uniformly from $\mathbb{Z}_q$ to the challenger and get challenge ciphertext $c$. If $c$ is the quadratic residue then ...

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So this is a solution I came up with based on this chat with @Maeher. We use proof by reduction to show if there exists an attacker $A$ with non-negligible advantage for $S_2$ we can use it to construct an attacker $B$ for $S$ with non-negligible advantage. If $$\Pr[vrfy(pk_0,m,\sigma_0) \;\; and \;\; vrfy(pk_1,m,\sigma_1)]$$ be non-negligible then easily ...

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This has indeed been answered previously and I'd be comfortable with it being closed as a redirect to prior answers. But just in case: No, but yes. These are signature schemes, they cannot be used like RSA. The specific thing you're proposing (directly encrypting a tiny amount of data without a hybrid encryption scheme) is not done. Notice that because key ...

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Indeed the text quoted is wrong; at the very least, by using incorrect vocabulary. That should be: if you sign a message with your private key, the paired public key can be used to verify the signed message's integrity and origin. What small amount of truth there is in the original statement boils down to: in some asymmetric cryptosystems, including RSA¹ (...

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@kelalaka's comment answers this very succinctly, but in the event that a slightly more in-depth explanation helps, here's my stab at it. The initialization vector is to encryption as a salt is to salted-hashing/key-derivation. It ensures that if in a given protocol the same values are used multiple times, a different initialization vector can allow the ...

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