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How do I generate decryption keys for the IDEA algorithm from the 128 bit key?

I am trying to implement IDEA algorithm in C#, just to learn how it works. I have taken a 128 bit binary key and generated the 52 encryption keys using the following code: ...
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How secure is this perl script to use an AES encryption on files? [closed]

I am not entierly sure if it is appropriate to ask such a question here, but then again, I don't know a better place. If it is the wrong place, let me know, and I will remove it. Could someone share ...
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PBKDF2 when dkLen and hLen have the same size

I was reading RFC 2898 and something is not clear to me. When I use PBKDF2 with SHA-256 and I want a derived key with length 32 bytes (the same length as my hash function output), your derived key ...
1answer
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I could imagine that, if the encrypted data is stored to a file, the IV is preppended at the ... 2answers 64 views Case insensitive verification of HMAC / Base64 signature I am signing a short message using the base64 of an HMAC, like this (python): ... 0answers 54 views How fast can a wrong decryption key be detected using ECC? When can a decryption function detect that the ECC key I use for decryption is incorrect? Is it possible to do that during initialization, or does the complete message have to be decrypted to do that? ... 1answer 53 views Why constrain the message lengths in indistinguishability in the presence of an eavesdropper? I need your help with a very basic concept in cryptography which I can't understand/prove on my own. I'm trying to prove and understand why, under "indistinguishability in the presence of an ... 1answer 42 views How is ElGamal not secure under chosen ciphertext attack, but semantically secure in some cases? I know that you can create a ciphertext c' using c and then find the corresponding m' for c' which you can use to find m for c. So, doesn't this mean that it is not semantically secure? But I also ... 1answer 50 views Chosen ciphertext insecurity in an ElGamal variant I'm trying to prove something and if I can show that there is a simple way to calculate$(g^a \bmod p)^k$if I know both$g^k \bmod p$and$g^a \bmod p$, then (I think) it will help me prove it, but ... 0answers 39 views Efficient decoding of irreducible binary Goppa codes and the role of matrix P in McEliece cryptosystem If we assume that the support for an irreducible binary Goppa code$\gamma_1, ..., \gamma_n$is publicly known, when is it possible to efficiently decode the code? I know it's possible if one knows ... 2answers 78 views DSA signatures with related k and unknown payloads Suppose that we are given DSA parameters$p$,$q$,$g$, a public key$y = g^x$, and two signatures$(r_1,s_1)$and$(r_2,s_2)$. We are told that$(r_1,s_1)$and$(r_2,s_2)$were produced by related ... 1answer 110 views Attack on DSA with signatures made with k, k+1, k+2 For homework, I'm asked to find the private key,$x$, in a DSA digital signature scheme. In the particular instance, we are given the parameters$p$,$q$and$g$, the public key$g^x$, 3 messages ... 1answer 153 views Understanding one-way hash functions construction I understand the needs that lead to the development of cryptography and I am quite familiar with the uses we make of the cryptographic tools. But, as a programmer, I am conditioned to see them as ... 2answers 133 views How can mega store my login details and still be secure? I understand how Mega's encryption works. For a quick summary of all those in the future looking for an answer on this... here is how it works: Upon first signing up for an account you make a ... 1answer 73 views What's the difference between “HashX-512” and “HashX-1024”? I need to make a Skein hash's, specifically, Skein-1024; however, I only have access currently to Skein-512. Is there any way to utilize a Skein-512 function to get the result of a Skein-1024 hash? ... 3answers 294 views “Weaknesses” in SHA-256d? According to this answer, "SHA-256d" was proposed in one of the Ferguson/Schneier books like so: SHA-256d(x) = SHA-256(SHA-256(x)) Apparently, the motivation for ... 2answers 122 views RSA digital signature vs authenticated cipher I want to provide both confidentiality and integrity for data at rest (many large files stored on disk). I plan to encrypt the data using AES, which will cover the confidentiality requirement. So ... 2answers 66 views Voice Call Safety [closed] When i was dealing with an assistant of my bank through mobile call, she asked me to insert my bank login code after a beep. I was wondering if this procedure is secure against a Man In the Middle ... 1answer 91 views What's the difference between Trapdoor Functions and Encryption Functions? From Wikipedia: A trapdoor function is a function that is easy to compute in one direction, yet believed to be difficult to compute in the opposite direction (finding its inverse) without ... 0answers 47 views Predicate Encryption supporting disjunctions I am not sure if I missed some subtlety in the definition of Attribute Hiding found in this paper on Predicate Encryption, but isn't it possible to construct a scheme for Predicate Encryption ... 1answer 55 views How to make a message into a polynomial on NTRU encryption? How to make a message into a polynomial on NTRU encryption? for example how we can conver 'hello world' to polynomial... i have read the converting operation on IEEE Std 1363.1- 2008, but i can't ... 1answer 98 views Client and server using same SSL certificate - any issues? I'm working on software where multiple components will communicate with each other using SSL. There would be one central component acting as a server, which would also require the clients to present ... 1answer 98 views Using encryption schemes for identification I've been researching how to implement a post-quantum SSL-like connection authentication, especially correct identification&authentization of the server/client. Because good post-quantum digital ... 0answers 97 views Single-purpose symmetric encryption scheme for single files I'm writing a simple password manager program that will encrypt/decrypt a single file (it's size will most likely stay under a few K). This is my initial file format design: ... 1answer 103 views Which MAC scheme is quantum resistant? will HMAC survive Grover algorithm ? if not then which MAC scheme provide post-quantum security ? 2answers 77 views Can two rc4 encoded messages be XORed and decrypted if encrypted with the same key? If I have the following: E1 = RC4(M1, K); E2 = RC4(M2, K); If two different messages M1 and M2 are encrypted with the same key, K, can the key be recovered by ... 2answers 92 views It is reasonably safe to leave a SSH private key with a 30+ character passphrase public? I'm curious about exploring uses for a distributing a single RSA private key with a passphrase instead of trying to secure the private key and distribute the public key. With the private key (and ... 1answer 200 views What does the expression$1^n$mean as a function argument? In a paper about predicate encryption or attribute based encryption, the setup function is mentioned with the$setup(1^n)$or$setup(1^l)$. I want to know what is meant here. Is it multiples of ones ... 2answers 150 views Why are RSA key sizes almost always a power of two? I know that other bit sizes are possible, e.g. this HTTPS server seems to have a 9000 bit key https://www.ssllabs.com/ssltest/analyze.html?d=qqq.gg, but it's very rare that one sees a key not of size ... 2answers 113 views one-time pad key related attack [duplicate] In one-time pads we always say do not use same key twice to encrypt ASCII messages, but if we use a random key to XOR a random ... 2answers 51 views How can two UProve token holders prove to a 3rd party that they aren't the same user? Suppose I have two users who are issued two different UProve IDs. The Issuer has guaranteed that one UProve token bearer will never have more than one UProve token ID. How can I use UProve to ... 2answers 85 views How do I unpack the x and y values from the BITSTRING in a DER ECDSA public key? In ASN.1, the X and Y values for a 256-bit elliptic curve key are stored as a single 66-byte ASN.1 BITSTRING. Are the values just the first and second half of this bitstring? The private key is an ... 0answers 78 views How to choose between AES-CCM and AES-GCM for storage volume encryption We are using the encryption built into Solaris 11 ZFS, which offers the choice between CCM (CBC counter mode) and GCM (Galois counter mode). What are the pros and cons of choosing each of these cipher ... 1answer 70 views Potential vulnerability in DH key selection - am I understanding this right? I'm reading through a DH implementation, and I think I found a potential hole. Public$p$and$g$values are properly selected. A candidate secret value$\bar a$is pseudo-randomly selected such ... 1answer 100 views How to design a practical and secure MAC scheme? I am sorry, but I need to introduce some concepts which are not directly related to cryptography to make myself clear, I hope I won't stun you with this ... (I'd rather explain it here than redirect ... 1answer 104 views Is SpookyHash vulnerable to HashDoS? Aumasson, Bernstein and Bosslet did an excellent job demonstrating fatal weaknesses in MurmurHash and CityHash, but what about SpookyHash? My first uneducated guess is that it would be much harder to ... 1answer 190 views Alice trusts Bob only when Bob trusts Alice some story first: Alice and Bob both have public/private key pairs. Now Bob wants Alice to sign his public key id. Alice agrees but only when Bob signs the public key id of her. Is this something ... 2answers 146 views Assymetric password encryption - Viable? Which algorithm? We have an application that requires cleartext passwords for user authentication because of the authentication mechanism in use (RADIUS/CHAP), which unfortunately we cannot change. Since we don't want ... 1answer 84 views Is it feasible to break Diffie-Hellman key exchange when the implementation uses a poor-quality PRNG? I've come across an implementation of DH in Java that uses the Random class to generate the secret integer value$a$, as shown in in Wikipedia's description of the ... 1answer 109 views Is this hand cipher any more secure than the Vigenère cipher? I know that inventing one's one crypto always sucks, but the problem is that hand ciphers are usually 1. very insecure 2. very slow. This is an attempt to make a relatively secure, keyable, and ... 1answer 39 views AES ENCRYPTION ALGORITHM [closed] What is the amount of decrease in the probability of decrypting a data encrypted using an AES algorithm? (That is by introducing each round out of ten whole rounds, how the probability of decryption ... 1answer 156 views What is the probability of breaking the AES algorithm? I am doing a project which requires the encryption to be done using AES. Is it really possible (technically) to crack AES? If yes, please tell me: What is the probability of breaking AES? How ... 1answer 75 views How to use HMAC for large ciphertexts over TLS HMAC used to secure chosen cipher-text attacks. if we are encrypting a large file (video) and sending it over TLS for decryption, how server can check MAC for ciphertext when we didn't sent whole of ... 1answer 94 views which asymmetric cipher provide highest performance? to get highest performance Which asymmetric cipher provide fastest encryption/decryption ? ECC or DH ? what key size is recommended today ? 1answer 129 views Solving hard problems in$\mathbb Z_{p}^{*}$when$\mathbb p$is close to$\mathbb 2^{n}$Suppose, for some security parameter$n$you choose a prime$p$such that$p = 2^n+c$for some relatively small$|c| < 2^m << 2^n$. I have seen such primes being called Pseudo-Mersenne Primes ... 6answers 304 views Where can I begin to study the math behind modern cryptography? I've been studying (more like breathing and eating) crypto for almost a year now, implementing algorithms, reading books, studying code, etc. The deeper I go in, the more I realize there is; I feel ... 0answers 80 views Secure modulus length for Diffie-Hellman What is secure modulus length for modular exponentiation so that finding discrete log is computationaly impossible? 1answer 36 views reduces the coefficients of a modulo 3 on NTRU i'm still don't understand about 'reduces the coefficients of a modulo 3' on NTRU tutorial$a = f*e = 3 - 7X - 10X^2 - 11X^3 + 10X^4 + 7X^5 + 6X^6 + 7X^7 + 5X^8 - 3X^9 -7X^{10} \pmod{32}.\$ Note ...

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