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Nov
1
comment How is digital signature different from a message authentication code (MAC)?
Explain the negative vote in order to improve :)
Nov
1
comment How is digital signature different from a message authentication code (MAC)?
no MAC is for message integrity.That is nobody has tampered with your message. Put it simpler an attacker cannot provide valid ciphertexts.
Nov
1
answered How is digital signature different from a message authentication code (MAC)?
Nov
1
comment Hash of multiset of values, which lets me compute the hash of the union
it sounds that you need a homomorphic hash function if exists
Oct
31
revised How to use HMAC-SHA1, HMAC-SHA2 in conjunction with AES
added 8 characters in body
Oct
31
answered How to use HMAC-SHA1, HMAC-SHA2 in conjunction with AES
Oct
30
comment How to develop a public key cryptosystem based on a hard problem?
Why do you need to propose this algorithm?Does it outperforms the existing ones?What you are describing sounds as a pseudorandom generator
Oct
29
comment How does order-preserving encryption work?
let us continue this discussion in chat
Oct
29
comment How does order-preserving encryption work?
Sorry my fault. But in Boldyreva's paper it is stated:"Below, we show that IND- OCPA is unachievable by a practical order-preserving encryption scheme, in that an OPE scheme cannot be IND-OCPA unless its ciphertext-space is extremely large (exponential in the size of the plaintext-space)" So the explanation by somebody would be ok lets make an exponential size of ciphertext space...
Oct
28
comment How does order-preserving encryption work?
So the exponential ciphertext space size is not needed at all with respect to security ?
Oct
28
comment How does order-preserving encryption work?
What are the other conditions for sufficient IND-OCPA?
Oct
28
comment How does order-preserving encryption work?
@pg1989 Also it would great to check your code :)
Oct
28
comment How does order-preserving encryption work?
@pg1989 but at some point in the paper it says that the ciphertext space should be exponential in the plaintext space. How this is put as input to an OPE?How we parametrize OPE with such info?
Oct
28
comment Calculating ciphersize of Paillier, SSE and OPE
@e-sushi Also the question for the OPE is: Should we apriori know and store all the plaintexts we want to encrypt with an OPE or/and the possible ciphertext values before encryption?
Oct
28
comment Calculating ciphersize of Paillier, SSE and OPE
@e-sushi I don't think the ciphertext size is exponential to the plaintext size according to the paper you provided. the ciphertext SPACE size is exponential to the plaintext SPACE size. The actual ciphertext is the output of AES according to the paper.
Oct
28
comment Secure order preserving hash function
@pg1989 if you can sum up the new results of the paper it would be great
Oct
28
comment How does order-preserving encryption work?
@pg1989 Do i have a priori to save all the codomain(possible output values) or just a range can do the work?The same question for the domain. I should know and save a apriori the values i want to encrypt?
Oct
23
comment Open source implementations of Symmetric Searchable Encryption and Order Preserving Encryption
Understand the design of these schemes and implement them :)
Oct
21
comment Security of cloud computational protocols in UC Framework?
@mikeazo so at the end you need a reductionist proof as with game-based proofs...So what's the different? What security definitions conceptually the ideal/real paradigm demonstrates that the game-based proofs does not, if any?To be more specific: Is there any case that even if Paillier is CPA you can end up in an insecure protocol by the security analysis with the ideal/real paradigm?
Oct
21
comment Security of cloud computational protocols in UC Framework?
@mikeazo. Can you give a protocol or a reference where its security is proven under the ideal/real paradigm. I mean to show how this indistinguishability between interaction of real and ideal environments is shown. Like you did but it seems very simplistic. I would expect at some point a reduction to a believed hard problem. For instance how the protocol you provided cannot be secure? Its security doesn't lie whether Paillier is CPA?