# All Questions

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### Can I discard a specific X509 signature from file?

I'm writing a program to sign files using X.509 certificates and .NET framework classes. My users can sign the same file more than once without any problem (like a revision process). So, a file may ...
23 views

### Meaning of Policy matches when signing SSL certificates

I was going over the process of doing a self-signed SSL certificate. The config file here is one of the inputs to this process (see: https://www.phildev.net/ssl/opensslconf.html) I have a question ...
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### How to design a balanced LFSR with period 1023 and linear span 55?

I am trying various combination of LFSR's to try to design sequence of period 1023. The linear span should be 55 and the output 1023 bits has to be balanced. I have tried with five LFSR's with degree ...
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### How does the openssl TLS implementation select the ciphersuite?

I would like to ask some help in pointing to me how the oopenssl TLS 1.2 server implementation selects the chosen ciphersuite? Does the server selects the first ciphersuite that is in the server's ...
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### What is the logic behind Compress function in iterated hash function

I am working on cryptographic hash functions theorems. In the iterated hash functions part a specific word started appearing constantly: "Compress" for instance within the "compress function". I am ...
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### Why is a known-plaintext attack considered a complete break?

I read somewhere that if a cipher has a known-plaintext attack, then it is considered completely broken. Say there is a cipher that someone uses where the algorithm is understood and a known-...
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### openssl AES, cannot decrypt with java [closed]

i'm using openssl to encrypt some data, which will decrypted with an java serverlet. Server isn't under my control, so i cannot install/modify anything on it. The question is how i can encrypt AES ...
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### Do I need output buffer to be multiple of AES block size for CTR mode? [migrated]

In my C code, I use OpenSSL's AES in CTR mode for encryption via EVP interface, that is I have something like this: ...
32 views

### What are the ways public-key can be distributed? [closed]

What are the ways public-key can be distributed?
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### SEAL Homomorphic multiplication

In SEAL homomorphic encryption library, there is an internal procedure to decompose a polynomial with large coefficients into a vector of polynomials with smaller coefficients. The procedure is ...
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### Least-weak way to authenticate using only AES ECB/CBC

I have an embedded application that needs to occasionally get secure updates from a server. The only crypto library I have available for the chip is an AES-256 cipher (ECB and CBC, encrypt/decrypt). ...
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### Do reversible black box obfuscators exist?

We shall say that an obfuscator $\mathcal{O}$ is a reversible black box obfuscator if for each reversible program $P$ the obfuscated program $\mathcal{O}(P)$ is still reversible but does not reveal ...
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### Why does Paillier have poor performance?

Can anyone explain to me why Paillier crypto system does not provide good performance? I read here (pdf) that RSA and ElGamal provide better performance than Paillier algorithm.
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### Can MGF1 within OAEP and PSS be replaced by a XOF?

Do we still need MGF1 as used in the PKCS#1 v2.x specifications for SHA-3 hash functions? MGF1 is currently used for OAEP and PSS as Mask Generation Function. Now that the SHA-3 specification contains ...
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### Differential privacy with oblivious transfer

I have the following scenario: A has encrypted text, with max length $L$; B wants to know if the decrypted text, which contains one or more words from a closed group of $X$ words; A is not to be ...
473 views

### Difference between a circuit and a normal function

I've seen the word circuit used in many crypto contexts (for example, regarding FHE in this pdf). I've always thought of a circuit as another word for a program or function. But is there a difference -...
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### RC4 Encrypting Plaintext, Key of 3 Bytes [closed]

Good afternoon! I tried to Encrypt a Plaintext of length of 3 Bytes with the Key of length of 3 Bytes, but it gave a wrong Ciphertext as I can't receive same Plaintext during Decryption process. I ...