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1d
comment Looking for C++/Python Open Source code library for cryptanalysis of classical ciphers
In my experience, pycrypto is not about the kinds of things you are talking about. Here is a related question on IT Security site.
2d
comment Why don’t all AES encryption tools produce the same key from the same password?
For a tool, use GPG.
2d
comment One-time-pad with multiplication
If there is no decryption routine, is it really encryption? I think more context would be helpful? What security do you need? Just confidentiality?
2d
comment One-time-pad with multiplication
This question is somewhat related.
2d
comment One-time-pad with multiplication
How do you do the inverse operation?
2d
comment Looking for C++/Python Open Source code library for cryptanalysis of classical ciphers
@MosheRubin not sure what "email to the moderator" you are talking about. Care to explain?
May
26
comment One time pad in CBC mode?
@Stefan: to add to what poncho says about impossibility. Correctly implemented OTP has a new pad every time. So, if I know the plaintext, I can get the pad, but that pad is never used again, so who cares. Same with CPA.
May
26
comment One time pad in CBC mode?
But how do you do CBC (which is for fixed length block ciphers) with OTP (which is an infinite length stream cipher)?
May
26
comment One time pad in CBC mode?
Is that what you are proposing doing?
May
26
comment One time pad in CBC mode?
It is unclear from your question how that would even work. CBC mode is used to take a fixed length block cipher and turn it into something that can encrypt larger messages. OTP is infinite length. Are you suggesting dividing up the plaintext into chunks and propagating cipher text somehow? Perhaps some equations would be helpful. For example, say you divide the plaintext and the key stream into 128 bit chunks. Let $p_0$ be the first 128 bits of plaintext and $k_0$ be the first 128 bits of key stream. Then $c_0=p_0\oplus k_0$. Then for all $i>0$, $c_i=p_i\oplus k_i\oplus c_{i-1}$.
May
26
comment Building a combined encryption scheme from two encryption schemes that's secure if at least on of them is secure
@gordon, the answer is, you can't delete this question. StackExchange is not a site to come to looking for answer and then delete them so that no one else can find them.
May
26
accepted Is HMAC-MD5 still secure for commitment or other common uses?
May
24
comment Executing encrypted code?
crypto.stackexchange.com/questions/1710/…
May
24
comment Common Modulus Attack in RSA
@rex don't forget to mark this as the answer by clicking the green check.
May
22
comment When to use RSA and when ElGamal asymmetric encryption
@Ragnagord also, if someone found a way to show that P=NP, that would not necessarily be a nail in the crypto coffin. See cases 2 & 3 of this answer.
May
22
comment When to use RSA and when ElGamal asymmetric encryption
@Ragnagord, right, but a break in RSA does not imply that P=NP. In other words, you could break RSA and still not know if P=NP. Your first comment says that breaking RSA involves proving that P=NP. That is not true.
May
22
comment When to use RSA and when ElGamal asymmetric encryption
@Ragnagord, Factoring is not known to be np-complete. So breaking RSA does not involve proving P=NP. This section of wikipedia is pretty good.
May
15
awarded  cryptanalysis
May
15
revised How do we guarantee plaintext is coprime in RSA?
added 283 characters in body
May
15
answered How do we guarantee plaintext is coprime in RSA?