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17h
revised Diffusion in Shamir's secret sharing scheme
inserted questions I'm responding to
19h
comment Diffusion in Shamir's secret sharing scheme
I think "additional security" should be changed to "additional secrecy". $\;$
19h
comment Diffusion in Shamir's secret sharing scheme
"..., then Shamir's secret sharing provides information theoretic security" against passive adversaries. $\;\;\;\;\;\;$ An active adversary can very easily and controllably affect the reconstructed secret. $\;\;\;\;$
20h
comment Diffusion in Shamir's secret sharing scheme
Note that, despite your notation, the exponent does not need to be prime. $\;$
20h
comment XORing a header with SHA512-hash - secure?
In that case, you could encrypt a prefix-free encoding of the plaintext with a stream cipher (such as CTR mode). $\:$ That would be faster than bit padding on the plaintext, although it would be restricted to somewhat larger ciphertexts. $\;\;\;\;$
21h
comment XORing a header with SHA512-hash - secure?
If you "want to add random bytes at the end" of the plaintext or the ciphertext? $\hspace{1.63 in}$
21h
answered Diffusion in Shamir's secret sharing scheme
21h
comment XORing a header with SHA512-hash - secure?
Yes. $\:$ You could skip that header and use bit padding on the plaintext. $\:$ Also, you should $\hspace{.98 in}$ use a MAC or some directly authenticated encryption. $\;\;\;\;$
1d
comment How to calculate Modulo using a standard calculator for a one time pad encryption
@user13120 : $\:$ You need to put in parentheses. $\;\;\;\;$
2d
revised ECDSA verification is too slow
fixed grammar, fixed capitalization, and removed irrelevant tags
Apr
17
revised One time pad: why is it useless in practice?
fixed typo in title
Apr
16
comment Composing hashes and/or MACs
That works for the usual conditions of unforgeability and pseudorandomness. $\:$ On the other hand, it does not work for the intermediate property of being a privacy-preserving mac. $\;\;\;\;$
Apr
16
revised Is anyone aware of Du atallah multiplicative secret sharing scheme for dot products for > 2 party scenario?
fixed link
Apr
16
comment Which commitment scheme is better for malicious models
What is "the one based on digital signatures"? $\;$
Apr
15
revised How can I convert numbers into prime numbers?
fixed grammar and removed irrelevant tag
Apr
15
revised SSL-like protocol with public-key hard-coded in the client
fixed grammar and a typo
Apr
15
comment Security of RSA for paranoids with padding?
One could just apply naked RSAP to something chosen at random and use a random oracle's $\hspace{.68 in}$ value at that thing as a key, although this approach would increase the ciphertext overhead. $\hspace{.96 in}$
Apr
15
comment Sequence of Encrypting RSA like Chaum Blinding scheme
One would check the signature's authenticity by checking whether or not $\:$ pow(claimed_signature,e,n) == digest(message) $\:$ is satisfied. $\;\;\;$ "Will unblinded_signed_msg == pow(message,d,n) satisfy" what condition? $\;\;\;\;\;\;$
Apr
15
comment Sequence of Encrypting RSA like Chaum Blinding scheme
Are you using Python? $\:$ Is "wayyy to long" more than 15 seconds? $\:$ My laptop was able to evaluate that for 25 random 2047-bit triples in under 7 seconds. $\:$ I would tackle this by making sure you're never computing pow(blinded_message,d), and then looking for other bugs you might have. $\:$ As far as I can see, the value of pow(signed_msg,r**-1,n) is completely irrelevant. $\:$ (I don't see a reason for anything involving r to be in the exponent.) $\;\;\;\;$
Apr
14
comment Sequence of Encrypting RSA like Chaum Blinding scheme
Which of the posts in that link are you talking about? $\;\;\;$ One signs on a blinded_message by computing $\:$ (blinded_message)^d % n $\;$. $\;\;\;\;\;\;$