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10h
comment To what extent is WhatsApp's statement on secure messaging realistic?
Which begs the question, how do they verify it has all the other properties?
2d
comment mode of operation in cryptography
@priyanka, not really. For CBC, if the message is not a multiple of the block size, you can pad. Sure that adds extra bytes, but who cares these days about a couple of extra bytes. I guess if you completely ignore security and define "best" as the most compact, you could argue that a streaming mode would be "best". Ignoring security, however, is not a good idea :)
2d
reviewed Approve mode of operation in cryptography
2d
answered mode of operation in cryptography
2d
comment Question about Cipher Block Chaining(CBC)
Are the 2 bits side by side? Can they cross a block boundary? Can the bits have the same value (in which case there would be effectively no change), or are you guaranteed that the two bits that are interchanged have different values (one is a 0, the other is a 1)? Overall, however, you are not correct. Swapping 2 bits would not make all bits of the plaintext incorrect.
Apr
26
revised How to prove that twice the application of a secure PRF stays secure?
added 141 characters in body
Apr
26
reviewed Approve How to prove that twice the application of a secure PRF stays secure?
Apr
25
comment Why only one secret value with Shamir's secret sharing?
@poncho, definitely. So it is good to have a link to the question.
Apr
25
comment Why only one secret value with Shamir's secret sharing?
@poncho, I'm not sure this is a duplicate. That other question seems to be asking about sharing a single secret but using other coefficients instead of the $x^0$ term of the polynomial. This one is asking about using sharing multiple secrets at once.
Apr
25
comment Searchable Encryption with Substring Search
Let me make sure I understand, you want to be able to encrypt a string, send it to some untrusted 3rd party. That 3rd party should be able to find patterns in the encrypted strings without the decryption key? Are these patterns supplied by the user?
Apr
25
comment Why only one secret value with Shamir's secret sharing?
Finite fields as opposed to what? Shamir's scheme is defined over a finite field.
Apr
25
comment Why only one secret value with Shamir's secret sharing?
What you are looking for is multi-secret sharing. It has been a while since I've read up on it, but there are plenty of papers out there on the topic.
Apr
22
comment Encrypt file using pycrypto RSA from python
Programming topics go on StackOverflow, if you want to ask about the more general security problem, I'd suggest Security.SE.
Apr
22
comment Encrypt file using pycrypto RSA from python
I'm voting to close this question as off-topic because it is a programming question not really a cryptography question.
Apr
22
comment Encrypt file using pycrypto RSA from python
Try this version of the code. As to what else I could do apart from using encryption?, we need to better understand the problem you are dealing with before we can really answer that.
Apr
22
comment Encrypt file using pycrypto RSA from python
I don't see in your code where you are calling rsa_keygen, so the code seems incomplete.
Apr
22
comment Encrypt file using pycrypto RSA from python
I think the following quote applies here: "If you think cryptography is the solution to your problem, then you don't understand cryptography and you don't understand your problem" - Roger Needham and Butler Lampson. If you are worried about the sudoers modifying the config file, so you want to encrypt it with RSA, where is the decryption key stored? It is likely needed, so where is it stored and why can't the sudoers read it?
Apr
21
comment What is the script tranferer in the turn intro?
I'm voting to close this question as off-topic because it is not about cryptography.
Apr
21
comment What is the script tranferer in the turn intro?
My guess is that it is something like this, which has nothing to do with cryptography.
Apr
19
comment How to crack unknown 8-bit encryption algorithm?
@fgrieu, since you don't know the algorithm, you have to assume you can generate (e.g., via an oracle) enough input/output pairs to build that dictionary.