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I'm an engineer with experience in applied cryptography, in particular in Smart Card systems.


Oct
4
revised Please punch holes in this authentication scheme
Detail the second attack wich was put into doubt; break the extension of the protocol; show no reapir is possible.
Oct
4
comment Hybrid encryption with RSA and AES versus spliting into multiple RSA messages?
@Markus: You write: "The generation of those one time keys took less than a blink of the eye. It was only about the speed afterward." That shows you did no benchmarks. Most if not all "good written standard and open source software" have 2048-bit RSA key generation (e=65537) at least 10 times slower than encryption using that key, often 1000 times.
Oct
4
revised Hybrid encryption with RSA and AES versus spliting into multiple RSA messages?
Remove unsafe
Oct
4
revised Hybrid encryption with RSA and AES versus spliting into multiple RSA messages?
generating an RSA key is _much_ slower than using it
Oct
4
revised Hybrid encryption with RSA and AES versus spliting into multiple RSA messages?
Add e=65537
Oct
4
revised Hybrid encryption with RSA and AES versus spliting into multiple RSA messages?
Pinpoint exatly what steps are wrong in the protocol
Oct
4
comment Hybrid encryption with RSA and AES versus spliting into multiple RSA messages?
@Markus: You write "a one time public key used for enciphering data without any other use is not the weak link nor a design error", and that's right. But sending that key only RSA-enciphered, as in the end of step 4 of your protocol, does not protect the integrity of that key; therefore an adversary can inject a false public key there, and then use the corresponding private key to decipher what's enciphered at step 5.
Oct
4
revised Hybrid encryption with RSA and AES versus spliting into multiple RSA messages?
Revise the equivalence of 2048-bit RSA
Oct
3
comment Decrypting a message without the private key using CRT
Hint: if $x$ is the message that you want to know, what do you know about $y=x^5$? And if you knew $y$, how would you get $x$?
Oct
3
answered Please punch holes in this authentication scheme
Oct
3
comment Please punch holes in this authentication scheme
@sukhvir: what's achieved by your protocol is no different from what's achieved by the simpler protocol (pointed by mikeazo) where your $K_A^-(R_B)$ is replaced by $R_B$, and $K_B^-(R_A)$ by $R_A$. If you think that the simpler protocol does not meet your goal, then your protocol does not meet its goal.
Oct
3
comment Please punch holes in this authentication scheme
@suhhvir: the sentence "Alice (then) encrypts Rb with her private key" is vague. First, a private key typically decrypts or sign, anything else must be defined precisely. Aloo, could it be that you considering the public (resp. private) xxcryption to be just $x\mapsto x^e\bmod N$ (resp. $x\mapsto x^d\bmod N$) where $(N,e)$ and $(N,d)$ are an RSA public/private key pair? That would be a serious (and classical) mistake. See e.g. this on the pitfalls of no or poor padding.
Oct
3
revised Hybrid encryption with RSA and AES versus spliting into multiple RSA messages?
changed more to less
Oct
3
revised Hybrid encryption with RSA and AES versus spliting into multiple RSA messages?
Shorten. Revise gap between RSA and AES key generation
Oct
3
revised Hybrid encryption with RSA and AES versus spliting into multiple RSA messages?
Shorten; lwiden tolerance of the gap between RSA and AES key generation
Oct
3
revised Hybrid encryption with RSA and AES versus spliting into multiple RSA messages?
proofread
Oct
3
revised Hybrid encryption with RSA and AES versus spliting into multiple RSA messages?
Attempt to answer the performance part
Oct
3
revised Hybrid encryption with RSA and AES versus spliting into multiple RSA messages?
Adapt to the revised question
Oct
3
revised Hybrid encryption with RSA and AES versus spliting into multiple RSA messages?
Adapt to the revised question
Oct
3
comment Can an RSA private key have several public keys?
In the second equation above, read $\phi(N)$ or $(p-1)\cdot(q-1)$ where there is $\phi(p-1,q-1)$, sorry.