instruction stringlengths 32 27.2k |
|---|
In game-based security definitions, like for example the one defining IND-CPA security, a given cryptosystem is said to be secure if any probabilistic polynomial time adversary has only a negligible advantage of winning the game, where the advantage is defined to be
$|Pr[b^{\prime}=b] - \frac{1}{2}|$,
being $b$ the a... |
Does redundancy in a file or data effect performance and security of encryption? (for example for AES, if not for general case)
Is it easier to encrypt something that has high redundancy or something that has almost no redundancy?
And does redundancy makes security weaker by any means?
|
I am not well versed in the field but I believe I know the basics.
All encryption algorithms that I know of utilize direct data manipulation to encrypt a message (string of bits) such as shifting, cycling, etc. in specific patterns utilizing the encryption key.
Is there any algorithm that instead of touching the data-t... |
I have a file containing 16-bit samples and I want to encrypt it, but the problem is that I need to be able to read any random 16-bit value from the file, and be to able to decrypt it, without reading larger (or surrounding) blocks. Because else it would require huge modifications to the device and driver.
It doesnt ne... |
I'm new to cryptography and have just encountered AES and SPN. I would like to know how the S-box, permutation step and the MixColumn step help improve security. It seems to me (perhaps mistakenly) that the security is provided solely by the key and that the substitution, permutation and MixColumn steps are redundant. ... |
I'm developing an application that will use public key authentication to contact some webservice. So the user has his keypair on his computer, and I want that file to be encrypted using AES with a key derived from a user's password.
I'm wondering if I'm using relatively "safe" parameters and way of writing the file.
He... |
Few block cipher modes has additional parameter , tweaks , especially the ones that are format preserving .
Now the comments section of this blog entry says such tweaks can be used for BIN numbers, expiration dates etc of credit card numbers.
How can tweaks be used to enforce such checks ?
what other ways tweaks can ... |
I am looking for a references for post-quantum threshold secret sharing schemes.
I am especially interested in knowing whether any one based on one-way compressor functions or cryptographic hashes exist.
The trivial secret sharing systems with $t=1$ and $t=n$ give information-theoretic security.
Here are some other alt... |
I'm trying to evaluate the correlation between key length and the number of messages that needs to be send to server during Cache timing Attack.
I read both
D. Bernstein, “Cache-timing attacks on AES,” April 2005. Department of Mathematics, Statistics, and Computer Science University of Illinois at Chicago.
Robert G. S... |
I am currently studying AES algorithm and writing a Code using Python.
I am trying to add 'Salt' into the user input password,
Here is what I am doing,
import hashlib
import os
password = "Sufiyan Ghori"
salt = os.urandom(32) # 32bytes * 8 = 256bits
# Adding the Password into the first 128bits of SALT
# So that the pa... |
Recently, T.Gowers wrote a blog entry called "How not to prove that P is not equal to NP" about the Razborov/Rudich Natural Proofs paper. He has a construction where he talks about compositions of 3-bit scramblers along with a paper on the subject. Boaz Barak replied to that post with the following comment:
Some other... |
I understand that if we have a secure PRG then the Goldreich-Goldwasser-Micali construction gives us a secure PRF.
However, what I've not been able to find much material on is how will the GGM construction fairs when the PRG is less than perfect.
Suppose we used AES-128 in CTR mode as the PRG to generate 256-bits of ou... |
In the BLAKE2 paper, the authors define
Maximal depth (1 byte): an integer in [1, 255] (set to 255 if unlimited, and to 1 only in sequential mode)
Node depth (1 byte): an integer in [0, 255] (set to 0 for the leaves, or in sequential mode)
Node depth is incremented as you approach the root node of the tree.
I was ... |
Are there any realties tests or criterias that prove the security of the PRNG?
What kind of tests or criteria?
|
Currently I am having a doubt, while making a "DES PCBC" encryption on an image I observe a bit of the silhouette of the image (Probably because of the XOR between plaintext blocks and ciphertext ones on the algorithm). That happens if I set IV and Key to 0.
However, if I change just the key (key in HEX values), the s... |
The verification algorithm given in blind signature. Should it work for both
Original message and the signature on it
Blinded message and the signature on it.
If yes, then how can we verify if the verification algorithm takes in a parameter which is computed during unblinding stage??
|
Without taking into account security, which hash function is the fastest one among the following:
MD5, SHA-1, SHA-2 (for various internal size), Keccak, and other… ?
|
Alice has two EC key pairs: $a_1$, $a_2$ are private keys (integers), $A_1$, $A_2$ are the corresponding public keys (points). Alice and Bob want to create a new public key $C$. Alice must prove that this key $C$ was created from exactly $A_1$ and $A_2$, i.e. Alice did not use other key pairs for $C$. The new public ke... |
Assume a website where people log in with their password.
The password is now stored in sql database as:
md5(password + random_salt)
We are adding the possibility for clients to stay logged in and I am trying to find out the best way to do that.
Passwords should stay stored in the DB as hashes using some hash functio... |
If I encrypt a file of a known format that has a lengthy header (e.g. an XML Excel file), does that render the encrypted file susceptible to a "known plain text" attack? In other words, if the first X bytes of the decrypted text are known, does that weaken the encryption for the remaining data?
|
Let $g$ be a generator of a multiplicative group $G$ of order $q$, $x$ be a private key, and $h=g^x$ be a public key of an exponential ElGamal cryptosystem.
Given a ciphertext $c$ produced as the ElGamal encryption of a given plaintext $m$, that is $Enc(m,h,r)=(g^r, g^m h^r)=(R,S)=c$, it is obvious that this ciphertext... |
I asked this question Will our app be FIPS 140-2 compliant if we use our own AES algorithm implementation here before and although there are some different thoughts about this, the general consensus seems to be that our application should be FIPS 140-2 compliant if we use a FIPS certified library.
We are using the AES... |
I wrote a basic function to test the speed of the AES-256-CBC mode of the Node.js built-in crypto functions. These functions use OpenSSL, so they should support AES-NI, but when I correctly enable AES-NI and do a command-line test of OpenSSL the encryption speed is ~350MB/s on OpenSSL and only ~100MB/s on Node.js Cryp... |
I recently discovered the Curve25519 key exchange lib and the Ed25519 signature lib. Due to the speculations about NIST-designed curves, there is a chance that I ditch them and use the curves above instead.
If I take the curve parameters from these two libs and use them in ECDH/ECIES and ECDSA respectively, will it be ... |
Consider the One-Time Pad (OTP). Suppose two parties, A and B, generate a completely random secret key in a real-life meeting, and they keep this secret. Now A wants to send some message to B using the OTP. The point is that in the OTP we can use any key only once. So we have to come up with a system to share a newly c... |
In cryptography, the Fluhrer, Mantin and Shamir attack is a particular stream cipher attack, a dedicated form of cryptanalysis for attacking the widely-used stream cipher RC4. The attack allows an attacker to recover the key in an RC4 encrypted stream from a large number of messages in that stream.
The Fluhrer, Mant... |
I would like to know if there are any security risks/gains from encrypting twice, i.e. $$\text{plaintext}\xrightarrow{encrypt}\text{intermediate text}\xrightarrow{encrypt}\text{ciphertext}.$$
I would like to know if there are known gains/risks to what I'm looking at. Perhaps certain pairs of systems are compatible whil... |
Is there a definied keysize to be used with the "AES_256-CBC" method in PHP, and what is the size?
Some background:
I want to store encrypted text into a PostgreSQL database. The user who posts the data has a key (stored in db) which gets appended to a generic private key hard coded in the library.
$key = $genericKey .... |
Suppose we consider the space of $\lbrace 0,1 \rbrace^{256}$ as the domain and SHA-256 as our hash function. Does SHA-256 become a one way permutation?
Has anyone tried to prove this? Or can it be shown that SHA-256 has more than one cycle under the given constraints?
|
I'm studying McEliece and Multivariate Public Key cryptographic systems. The main problem here is the huge key size.
Is there any restriction in using lossless compression algorithms to fix this problem?
|
Suppose Alice has two primes $p$ and $q$ such that $p\equiv q \equiv 3 \pmod 4$. $n=p\cdot q$ is part of her certificate to identify her. A party say Bob, sends her a random quadratic residue ${}\bmod n$, say $x$. To identify her, Alice computes $y$, a square root of $x$ and send it to Bob. He simply verifies $y^2\equi... |
If you've only got an encrypted data channel can you actively sidestep the encryption and communicate with an outside party who can see the data but cannot decrypt it?
Yes - if you can find some leaky aspect in the process that's still visible after encryption.
Is there a name for this? And is scheme I came across rece... |
If I follow the wikipedia or crypto.stackexchange definition, any simple XOR encryption where the key is as long as the plain text should qualify as a secure block cipher.
Now I thought what would happen if I just use this together with a block cipher mode of operation? After all, they should build a secure scheme wit... |
I'm reading a paper about MACs and I would like to be sure about the meaning of a security beyond the birthday paradox.
Is there a definition?
|
The NaCl web site says this is a requirement of the API, but its seems more than just an API issue. It means the first 32 bytes of the first salsa20 block are effectively ignored. I didn't see anything in the documentation that explains the reason for this.
Does ignoring the first 32 bytes of the first salsa20 block im... |
Help me understand the following. With WBC the question is mainly being stated as can one try to break WBC to identify the key. My question is: Why would one ever want to do that anyways?
If one can locate the WBC itself it should be enough to enc/dec anything she wants with the embedded key. To me it comes to chicken ... |
Evaluate the speed of the algorithm GCM AES-128 and compare it whith speed of one of the stream chipher in eSTREAM. Can someone give such an assessment?
|
I understand that using Grover's algorithm it only requires $2^{64}$ lookups for a 128 bit AES encryption, leading people to say we need to increase to 256 bit keys. But how long would it actually take a quantum computer to do $2^{64}$ lookups?
I can't say I fully understand quantum computers, but aren't people making... |
I'm trying to understand how the AES S-Boxes are calculated. I understand how the multiplicative inverse is calculated over $GF(2^8)$, but I'm confused by the description of the affine transformation. I haven't been able to Google a good explanation of how the S-Box values are calculated. Can someone explain how this w... |
Are any Certificate Authorities using 4096 bit keys for their intermediate and root certificates?
I know you can, of course, use a 4096 bit key for your server certificate, but I usually see 2048 bit keys from the Certification Authorities, and wonder if any are using 4096 bit keys yet?
Thank you.
|
As we can see in the picture we have a multiplication in this algorithm,
we know that two 16 bit inputs should have a 32 bit output, but here we just use 16 bits of the 32 bit output.
For decryption we can reverse the algorithm from bottom of the algorithm to top, but how can we invert the multiplication that produced... |
I'm taking a cryptography class and I come across these terms dense and sparse key space allt he time. What do they mean?
As far as I can I understand, dense key space means that there are more combinations of the keys in that particular space and sparse the opposite. If yes, assuming I use elliptic key cryptography i.... |
I have seen from time to time questions about various OTP schemes and "OTP" (i.e. stream cipher) schemes. The most common OTP troubles appear to be:
How to extend size of previously generated key or how to generate key.
How to get key material securely to the recipient.
In electronic communication or storage encrypti... |
Reading through the DES Specification it says that the keys are permuted with PC-1 initially and then shifted left both $C$ and $D$. However, before it gets permuted again through PC-2 it does not mention how $C$ and $D$ are put together before going through PC-2.
Is it assumed that $C$ is the lower half of the input ... |
I was wondering whether it is safe to use the same DH or ECDH key pair in more than one key agreement, particularly if these public keys are in a public registry. These public keys could be used by your counterparts (who also have their public keys in the same registry) to agree on a secret used to send you a message, ... |
I'm working on a Java authentication subsystem that specs the storage of passwords in the DB as PBKDF2-generated hashes, and I'm now trying to decide whether I should use SHA1 or SHA512 as PFR. I'm under the impression that the consensus is that SHA1 has some theoretical weaknesses, and that SHA512 should be chosen ins... |
I'm using Blowfish in a toy Diffie-Hellman communications scheme. Random session keys are generated for each connection.
In this case I can simply feed a null array to the IV right? The same plaintext would never be encrypted with the same keystream.
|
I have installed a python implementation of scrypt and noticed it has several functions, both an encrypt and hash function. Yet Wikipedia lists it as being used for PBKDF instead of PBKDF2. Is scrypt a hashing function for PBKDF2 or is it on its own an alternative?
|
The 64 bit machine's biggest number can be 2^63 (9,223,372,036,854,775,807). So what kind of a monstrous machine can generate 100-400 digits prime number? I probably don't understand something, so that's why I am asking.
|
So, having read a variety of documentations on AES encryption, I came to the unknowledgeable conclusion that the key schedule applied to the array of chunks, and not just the 14 cycles on a single chunk. Thus I concluded that AES was not a linear hash, such that ciphering sequential equivalent chunks would produce a se... |
I have come up with an encryption algorithm and I am looking for a place to possibly publish it. Any ideas?
|
Given a protocol, if we can reduce breaking the protocol to a hard problem, such as DLP or CDH, we can say that this protocol is secure.
Theoretically speaking, reduction is a good method to prove the security of a protocol. As to key-exchange protocols, if the reduction method uses the adversary as a subroutine, the s... |
I recently began using PGP desktop and found several options for my encryption capabilities. Firstly, which of these (AES, CAST, Triple DES, TwoFish, IDEA) is the most recent? Secondly, may the NSA not have the keys to decrypt? Are there any encryption protocols not listed that are perhaps safer to use?
After reading t... |
I have a lot of objects, all of which need a particular number tagged on them so I can quickly tell the customer accordingly. But the problem is that the customer should not know what these numbers say (I write how much I buy the object for).
Is there any way I can encode them so that i can quickly decode and understan... |
I have to implement a 256*256 bit Montgomery multiplier for pairing computations. The straightforward approach is to use a bit-serial version, but I would like to utilize the built-in 64*64 bits multipliers on soft cores of modern FPGA devices, therefore I need a blockwise implementation (64 bits each). Two choices for... |
I was wondering if I have the key and the encrypted Hill Cipher message(s). I can definitely figure out the charset involved. But the order is missing. Assuming that I use 37 modulo or higher. How would I go about cracking it?
|
Following the recent government hacking (and subsequent news and fallout), I'm wondering what crypto-systems remain strong (and why) and what crypto-systems were exploited too heavily to be reliable. I'm wondering what will remain strong for the foreseeable future and why these systems were not affected (while the othe... |
According to the paper “GQ and Schnorr Identification Schemes: Proofs of Security against Impersonation under Active and Concurrent Attacks” by Mihir Bellare and Adriana Palacio, the Schnorr identification scheme is secure under an active adversary who changes messages. I have been told that Schnorr is actually not sec... |
Shamir's Secret Sharing allows a secret to be split into multiple shares so that it can be reconstructed later.
Is there a way to do the reverse? Can we combine a few secrets first and later split them into their original forms? More clearly: given two strings I want to "pack" them into single secret and later split t... |
I have been reading up on RSA attacks and came across one that could be called a least-significant-bit (LSB) oracle attack.
For the sake of clarity lets define RSA primes $(p, q)$, private key $d$ and the public key $(e, N)$ where $N$ is the modulus.
Now assume an oracle exists that will decrypt a given ciphertext $C$ ... |
I would like to insert a key deriving function into EAX mode, in order to hamper brute-force attacks for a key-size restricted cipher (56 bits). The modification inserts an identical multi-block pattern $S$ behind the corresponding tweaks:
Original: $OMAC(T||...)$ where the 128-bit tweak $T$ is either 0, 1, 2.
Modifica... |
Despite the fact primality test is a mathematical issue, it plays a part on the security of many cryptosystems such as RSA. I was trying to understand how it works until I came to the following congruency:
〖(X+a)〗^p≡X^p+a (mod X^r-1,p)
The above reduces evaluating the initial congruency 〖(X+a)〗^p≡X^p+a (mod p) to hav... |
I have the following A Encrypted file and the same file in its original(not encrypted) form
Now will it be possible to find the encryption/decryption key by comparing the the above two files are there any known programs that can help me.
any help will be highly appreciated
edit: I have uploaded the two files as zip fil... |
I cannot seem to understand the role or goal of Quantum Fourier Transformation in Shor's integer factorization algorithm. Is it used to collapse all quantum states into one, in which it has a factor of a given input $n$?
|
I have a simple question about the use of random variables for encryption schemes, to make sure my intuition is correct.
We say $P(K = k)$ to represent the probability that a particular key $k$ is chosen by the probabilistic algorithm Gen. Formally, $K$ is a random variable that denotes the value of the key.
So the ex... |
I'm trying to generate a signature for DSA with the following parameters:
$p = 23$ , $q = 11$ , $g = 3$ , $H(m) = 8$ , $x = 5$
for the life of me, I cannot choose a random $k$ ($0 > k > q$) that will give me $r$ , $s$ that 'add up' when calculating $w$, $u1$, $u2$, and verifying.
I don't know if I'm just doing my math... |
I'm using "eCryptfs" on several directories on my dedicated Debian server. I mount them manually via
mount -t ecryptfs [dir] [mountpoint]
But after some weeks being mounted it's not easy to remember the exact passwords for each directory. I want to make sure that I got the right passwords before unmounting them or re... |
Consider an outsourced database to an untrusted cloud (think CryptDb), the question is how to compute a function $f(.)$ on the data.
I think I understand how (fully or partially) homomorphic encryption works in this situation:
Encrypt the input.
Outsource both the ciphertexts and the (public) function.
The cloud ... |
If an RSA encryption uses a modulus $n$ of 15000 bits and $e = 3$ or $e = 2^{16} + 1$, how many squarings and multiplications will we need for encryption, and for decryption? Could you please explain the concept of square and multiply as well?
I'm thinking the number of squarings is going to be equal to the number of $... |
I´m trying to follow one of the very detailed RSA Proofs given by di-mgt: "RSA theory", but unfortunately I stuck at the beginning of solution (chapter 3).
I don´t understand where the second part of (8) is coming from:
$RsaPrivate(RsaPublic(m))\ =\ (m^e\ mod\ n)^d\ mod\ n\ =\ m^{ed}\ mod\ n$
How is it reduced? Where ... |
If we encrypt a message twice with symmetric key $k_1$ first and then $k_2$ like $E_{k2}\{E_{k1}\{m\}\}$ , ideally we should decrypt with $k_2$ first and then $k_1$ but is it possible to decrypt with $k_1$ and then with $k_2$ ? Using any of the AES Modes preferably ?
|
I am implementing AES 256-bit Algorithm from the Theory given in the book, "Cryptography and Network Security" by Behrouz A. Forouzan.
The Algorithm described in the Book in relation to Key Expansion, defines AddRoundKey like this:
From the given 32-Bytes Cipher Key, I am supposed to generate 4 * (Nr + 1) words. Nr be... |
This is a multi-layer problem, and I want to take you through the whole thing rather than just asking about IVs. Bear with me. Also, all code below is in Common Lisp because that's what I'm using, but if there are any complaints, I'll edit to put up pseudocode.
I'm trying to put together a procedure which will produce... |
I'm trying to calculate Rijndael key schedule "Rcon" values manually. I know how to calculate each value with the equation rcon(i) = x^(i-1) mod x^8 + x^4 + x^3 + x^1 + 1, for example:
recon(10) = x^(10-1) mod x^8 + x^4 + x^3 + x^1 + 1
x^(9) mod (x^8 + x^4 + x^3 + x^1 + 1)
=> x^5 + x^4 + x^2 + x
=> 0011 0110
=> 0x36 (1... |
When doing cryptanalysis on RSA or something number theory based, there are various attacks that all seem to involve number theory (Wikipedia: RSA_(algorithm) ~ Attacks_against_plain_RSA).
Similarly, attacks on ECC seem to involve something from ECC (Elliptic curve cryptography related key attacks).
What I'm wondering... |
I was just reading the Stick Figure Guide to AES and came across an interesting table explaining how the winner was chosen:
Unfortunately the NIST site is down so I can't gain further information about the approval process so I was hoping someone here would know in more detail.
Who or what decided on the numbers in t... |
I am having trouble understanding the prime number theorem.
As part of some revision for an exam, I am trying to answer the following questions (but seeing as I don't understand the concept of the prime number theorem, I'm not doing too well):
Question 1:
What is the proportion of numbers that are prime up to 1,000,000... |
Are the proofs based on a PRF assumption still valid when using a variable-length input PRF ?
The answer might be obvious, but I have a doubt.
|
Is $mac = enc(hash(x))$ a secure MAC for hash = SHA256 and enc AES in CBC mode or ECB mode. Normally AES-CBC is malleable. But in this case I use a hash function for the one-way property.
For example, an attacker can change the iv vector:
In CBC c[0] = enc(m[0] ^ iv) an attacker chooses m'[0] and computes iv' by m[0]... |
I want to partially encrypt a large block of data using AES. Meaning: given plaintext[0:1100], I would like to encrypt plaintext[0:1023]. The plaintext is generally machine code, but might have snippets of text.
Does this expose what I encrypted to any realistic challenges in the context of my application (for example... |
Ok, I just jumped into crypto and now struggling with some points…
I read lots of resources, most of them mention how important the strength of the encryption key is. However, I could not find much info about that.
What if the encryption key is not generated randomly and somehow is fixed or easy to be guessed? And wha... |
Some time ago, I asked how to encrypt small messages like e.g., four decimal digit numbers (banking PINs). I've got my answer, but also a warning like it makes no sense as it's easy to guess: Even having no information at all and bad luck implies 10000 trials only, which is nothing in crypto.
However, at an ATM you hav... |
I've been looking for a simple which signs a number with some randomly generated key and then verified(decrypts the original number) with the public key, which is generated by the private.
All the examples I've found does not feature an example with real numbers, and all the keys/numbers described with a single letter,... |
AES-128 requires 10 rounds ( AES Description, Wikipedia )
However Bruce Schneier has recommended AES-128 use 16 rounds ( Schneier on Security: New Attack on AES )
Could that be implemented as two full encryptions of AES-128? That is:
AES_128_ENCRYPT(key, data, mode); // 10 rounds of normal AES 128
AES_128(key, AES_128(... |
Alice publishes $(n,e)$ where $n$ is exponential modulus and $e$ is the public key. We have $n=80$ digit number and $e=3$. Bob, in correspondence with Alice, asked Alice to prove she is really Alice, by making her signature on the following five numbers: $m1, m2, m3, m4, m5$. Then Alice sent 6 numbers $y1, y2, y3, y4, ... |
I know that length prepending improves security of CBC-MAC. However, wouldn't inserting the length elsewhere (middle, end or any other part of message) be equally good? After all, even the length is processed by the underlying cipher block.
|
What is the difference between the term cipher (a name like RIJNDAEL) and mode of operation (like ECB)?
Aren't these both terms for the encryption/decryption technique?
|
What's the definition of non-linearity of a boolean function? Roughly saying it is minimum number of times it equals any affine function. But I don't get it mathematically.
For example, if $f = x_1x_2$, then all the affine functions are $g_1 = 0$, $g_2 = x_1$, $g_3 = x_2$ and $g_4 = x_1+x_2$, then the non-linearity of ... |
In the Wikipedia article "Bent functions",
there are some figures representing those Bent functions:
How do these figures represent a boolean function ?
|
I found a theorem that says:
Let $MAC = (S,V)$ be a MAC for short messages over $(K,M,T)$.
Let $H: M^{big} → M$.
Define $MAC^{big} = (S^{big},V^{big})$ over $(K,M^{big},T)$ as:
$S^{big}(k,m) = S(k,H(m))$ and $V^{big}(k,m,t) = V(k,H(m),t)$.
Theorem: If $MAC$ is a secure mac and $H$ is a collision-resistant hash function... |
I am presently implementing the serpent block cipher in C++ following the specifications. It's important to mention that I'm implementing the cipher in bitslice mode. You'll need the The full submission package of Serpent which contains the specification of the algorithm and the source code in C and Java.
Lets start w... |
I have been reading Bleichenbacher's 1998 paper on a forged message attack on RSA. The paper assumes access to an Oracle that takes a ciphertext $c$ and will check the decrypted text for valid PKCS #1 padding and returns the validity of the padding. This side-channel can be used for an attack since we can send a forged... |
The traditional authenticated DH protocol with PFS against active adversaries, ensures that the compromise of both party's long-term private keys after the session is completed will not help the adversary to compute session key, even adversary gets involved in the generation of messages.
An ID-based key-exchange has s... |
In my application, I am generating a big random number and publishing a SHA256 hash of it. After the hash it published (but not the secret), anyone can submit any number, and the system will calculate and present them a SHA256 hash of the number derived by concatenating their number at the end of the secret number from... |
How can someone estimate the number of years needed to factor an RSA key based on the advancement of technology if followed Moore's law?
|
To formulate this question precisely, I will define an idealized hypothetical "perfect" hash function $H(n)$ which has nice scalability properties, and will formulate a problem PERFECT HASHCASH in terms of that, understanding that practical considerations may end up yielding only an approximation of this ideal.
To keep... |
Let's assume Bob and Alice has a secret key for MAC. If MAC is constructed by the key and the message, that means that both Alice and Bob can construct the exact same message and MAC. So, Bob can claim Alice created certain message, not him. What's the point to use MAC then? Why not just use symmetric encryption?
|
I know that this is not the best use case for RSA, but for a customer of mine I have to encode user data on the server in a way so that it can be decoded/downloaded by the customer through a "secure" webpage.
Workflow
Users can register on the page and leave some sensitive data (no credit card data, but age, name, addr... |
Is there an encyption scheme that combines additive homomorphism with ability to proxy re-encrypt? I've tried digging around on the Internet but haven't found anything conclusive on the topic.
|
I'm looking at Secp 256K1 vs UProve's FIPS 186-3 or P-256 implementation. Is there any relationship between the curves such that I can consistently "map" or "project" values from one curve to another?
Is this a good idea? (What faults could crop up when doing so?)
My goal is to allow for two independent crypto system... |
Subsets and Splits
No community queries yet
The top public SQL queries from the community will appear here once available.