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Using AES-128 with only 64-bit uniform random is not secure. There are many entities around that can break this easily by searching the $2^{64}$- space. See the details here;
- [How reassuring is 64-bit (in)security?](https://crypto.stackexchange.com/a/63537/18298)
Only possible additional complexity that you can... |
ChaCha has clear delineations between key, nonce, counter and constants.
What is the reason for not using a XEX approach such that the ChaCha key is 512 bits and all the other things are XOR'ed with the key, and only the key is XOR'ed with the ChaCha permutation output?
ChaCha already has some similarity to Even-... |
ChaCha has clear delineations between key, nonce, counter and constants.
What is the reason for not using a XEX approach such that the ChaCha key is 512 bits and all the other things are XOR'ed with the key, and only the key is XOR'ed with the ChaCha permutation output?
ChaCha already has some similarity to Even-... |
ChaCha has clear delineations between key, nonce, counter and constants.
What is the reason for not using a XEX approach such that the ChaCha key is 512 bits and all the other things are XOR'ed with the key, and only the key is XOR'ed with the ChaCha permutation output?
ChaCha already has some similarity to Even-... |
ChaCha has clear delineations between key, nonce, counter and constants.
What is the reason for not using a XEX approach such that the ChaCha key is 512 bits and all the other things are XOR'ed with the key, and only the key is XOR'ed with the ChaCha permutation output?
ChaCha already has some similarity to Even-... |
ChaCha has clear delineations between key, nonce, counter and constants.
What is the reason for not using a XEX approach such that the ChaCha key is 512 bits and all the other things are XOR'ed with the key, and only the key is XOR'ed with the ChaCha permutation output?
ChaCha already has some similarity to Even-... |
ChaCha has clear delineations between key, nonce, counter and constants.
What is the reason for not using a XEX approach such that the ChaCha key is 512 bits and all the other things are XOR'ed with the key, and only the key is XOR'ed with the ChaCha permutation output?
ChaCha already has some similarity to Even-... |
ChaCha has clear delineations between key, nonce, counter and constants.
What is the reason for not using a XEX approach such that the ChaCha key is 512 bits and all the other things are XOR'ed with the key, and only the key is XOR'ed with the ChaCha permutation output?
ChaCha already has some similarity to Even-... |
Using AES-128 with only 64-bit uniform random is not secure. There are many entities around that can break this easily by searching the $2^{64}$- space.
| Machines | in a second| in an hour| in a day| in a year|
|:----|---:|----:|----:|----:|
|Summit on SHA-1 | $\approx 2^{49.7} $ | $ \approx 2^{61.5}$ | $\approx ... |
We will continue our [previous topic](https://crypto.stackexchange.com/questions/108051/can-i-move-elements-from-cyclic-subgroup-to-its-cyclic-parent-group?noredirect=1#comment231108_108051) here⬇️ for clarity...
***The following context is based on elliptic curves in short-weierstrass form y^2 = x^3 + b.***
**pl... |
We are working in the elliptic curve group named [secp256k1][1] over prime field $\mathbb F_p$. The group law is noted $+$, known as point addition (point doubling in the special case of adding a point/element to itself). The group's unity (aka neutral, aka point at infinity) is noted $\mathcal O$. Other elements of th... |
We are working in the elliptic curve group named [secp256k1][1] over prime field $\mathbb F_p$. The group law is noted $+$, known as point addition (point doubling in the special case of adding a point/element to itself). The group's unity (aka neutral, aka point at infinity) is noted $\mathcal O$. Other elements of th... |
We are working in the elliptic curve group named [secp256k1][1] over prime field $\mathbb F_p$. The group law is noted $+$, known as point addition (point doubling in the special case of adding a point/element to itself). The group's unity (aka neutral, aka point at infinity) is noted $\mathcal O$. Other elements of th... |
Using AES-128 with only 64-bit uniform random is not secure. There are many entities around that can break this easily by searching the $2^{64}$- space.
| Machines | in a second| in an hour| in a day| in a year|
|:----|---:|----:|----:|----:|
|Summit on SHA-1 | $\approx 2^{49.7} $ | $ \approx 2^{61.5}$ | $\approx ... |
I recently came across the theorem about $n$-way nesting. It states that if $\mathcal{E}=(E, D)$ is semantically secure, then $\mathcal{E}$ is secure for $n$-way nesting. I'm trying to prove the specific case of $n=2$. <br>For the encryption $c\leftarrow E(k_1, E(k_0, m))$, the adversary provides $(m_0, m_1)$ to the ch... |
Why doesn't ChaCha use a 512bit key and xor parameters into it? |
ChaCha has clear delineations between key, nonce, counter and constants.
What is the reason for not using a XEX-like (k=0) approach such that the ChaCha key is 512 bits and all the other things are XOR'ed with the key, and only the key is XOR'ed with the ChaCha permutation output?
ChaCha already has some similari... |
ChaCha has clear delineations between key, nonce, counter and constants.
What is the reason for not using a XEX-like (k=0) approach such that the ChaCha key is 512 bits and all the other things are XOR'ed with the key, and only the key is XOR'ed with the ChaCha permutation output?
ChaCha already has some similari... |
I have been reading about lattice attack on ECDSA when partial bits of nonce are known for amount of signatures, So i went through some source code trying to understand how it works.
First of all, Here are the formulas i know.
pk = d*G
r => (k*G).x mod n
s = (k^-1*(z+r*d)) mod n
k = s^-1*(z+r*d... |
Can lattice attack work MSB or LSB are unkown but 16 bytes of private key are known? |
ChaCha has clear delineations between key, nonce, counter and constants.
What is the reason for not using a XEX-like ($k=0$) approach such that the ChaCha key is 512 bits and all the other things are XOR'ed with the key, and only the key is XOR'ed with the ChaCha permutation output?
ChaCha already has some simila... |
As is well known, a sigma protocol can be transformed into a NIZK protocol through fiat-shamir transform.
But can the sigma protocol be transformed into a signature of knowledge in a similar manner？
Intuitively, it seems possible, but which research studies have directly proven this issue? |
In secp256k1 elliptic curve if a point is given let's say __Q__ and the slope is calculated from the given point using point doubling formula which will be use to derive a new point on the curve let's call it __R__, using only the calculated slope(__s__) and the new point __R__ how can I validate if the slope is corr... |
# Context
- An unknown modulus N with 8 unknown prime factors $p_1, p_2, p_3, p_4, p_5, p_6, p_7, p_8$
- a plaintext $m$ is encrypted with the formula $c = 2^m \mod N$
- the only things the attacker know are $c$ and $\sum_{i=1}^{8}(a|p_i)$ for any real number $a$ with $(a|p)$ being the Legendre Symbol of $a$ and $p$... |
# Context
- An unknown modulus N with 8 unknown prime factors $p_1, p_2, p_3, p_4, p_5, p_6, p_7, p_8$
- a plaintext $m$ is encrypted with the formula $c = 2^m \mod N$
- the only things the attacker know are $c$ and $\sum_{i=1}^{8}(a|p_i)$ for any integer $a$ with $(a|p)$ being the Legendre Symbol of $a$ and $p$
... |
This paper[1] defines the *simulatability* and *extractability* of the signature of knowledge (SoK).
As is widely known, a secure signature scheme should be both unforgeable and non-malleable. Can we derive unforgeability and non-malleability from extractability? （Intuitively, non-malleability seems like it can be ... |
If a SoK satisfies simulatability and extractability, is this signature unforgeable and non-malleable? |
Consider how a [cheque](https://en.wikipedia.org/wiki/Cheque)-book works: Alice goes to the Bank, and gets some incomplete messages, like `Alice would like the Bank to give _____ (or the bearer of this paper) the following: _____`. This message is verifiably from the Bank, because it's written on a special paper, howev... |
Signature algorithm/protocol with fillable gaps? |
I read the question as: knowing the coordinates of $R$ of secp256k1 and an integer $s$, how do we validate that $s$ is the slope at the point $Q$ of secp256k1 such that $R=2Q$ ?
One way would be computing $Q=((n+1)/2)R$ by point multiplication as in [this answer][1], then computing the slope at $Q$ and comparing to ... |
I read the question as: knowing the coordinates of $R$ of secp256k1 and an integer $s$, how do we validate that $s$ is the slope at the point $Q$ of secp256k1 such that $R=2Q$ ?
One way would be computing $Q=((n+1)/2)R$ by point multiplication as in [this answer][1], then computing the slope at $Q$ and comparing to ... |
I read the question as: knowing the coordinates of $R$ on [secp256k1][1] and an integer $s$, how do we validate that $s$ is the slope at the point $Q$ on secp256k1 such that $R=2Q$ ?
One way would be computing $Q=((n+1)/2)R$ by point multiplication as in [this answer][2], then computing the slope at $Q$ and comparin... |
knowing the coordinates of $R$ on secp256k1 and an integer $s$, how do we validate that $s$ is the slope at the point $Q$ on secp256k1 such that $R=2Q$ ?
Below is a python3 script implementation of the calculation I have tried, which works correctly for only points derived using point doubling formula.
```python3... |
I read the question as: knowing the coordinates of $R$ on [secp256k1][1] and an integer $s$, how do we validate that $s$ is the slope at the point $Q$ on secp256k1 such that $R=2Q$ ?
One way would be computing $Q=((n+1)/2)R$ by point multiplication as in [this answer][2], then computing the slope at $Q$ and comparin... |
I read the question as: knowing the coordinates of $R$ on [secp256k1][1] and an integer $s$, how do we validate that $s$ is the slope at the point $Q$ on secp256k1 such that $R=2Q$ ?
One way would be computing $Q=((n+1)/2)R$ by point multiplication as in [this answer][2], then computing the slope at $Q$ and comparin... |
Is there any formula for deriving the $y$-coordinate using the $x$-coordinate and the slope in the secp256k1 elliptic curve?
For example:
Calculate the slope:
```
slope = 75359724952757581356787150982223137069297282952438962440225639443485944634025
```
Calculate the new $x$-coordinates:
```
x = 11271166... |
> Knowing the coordinates of $R$ on [secp256k1][1] and an integer $s$, how do we validate that $s$ is the slope at the point $Q$ on secp256k1 such that $R=2Q$ ?
One way would be computing $Q=((n+1)/2)R$ by point multiplication as in [this answer][2], then computing the slope at $Q$ and comparing to $s$.
But there... |
I am currently leaning about LFSRs.
I was told that a binary LFSR with length m has a form of **sm = a0s0 + a1s1 + ... + am-1 sm-1** where **a0 ... am-1** are binary numbers.
**a0 ... am-1** are hidden and we are given the output stream of bits **(01101010....)**
How can I determine the coefficients from the g... |
This [article][1] provides the security role of key blinding in Ascon. Key blind in Ascon is the key xored with capacity part after the permutation in initialization and finalizations stage.
[![enter image description here][2]][2]
quoting from the paper:
> we demonstrate that Ascon without key blinding (i.e... |
I'm trying to show that the PRG $G$ defined as below is insecure for any binary matrix $A$.
\begin{align}
A&: m\times n& (n < m)\\
s&: n\times 1\\
G&: \{0, 1\}^n\rightarrow\{0, 1\}^{m} \\
&G(s)= (A\cdot s) \bmod{2}
\end{align}
As far as I know, I need to provide an adversary with non-negligible advantage, or p... |
I guess $s_m=a_0s_0+a_1s_1+\ldots+a_{m-1}s_{m-1}$ is the equation giving the next bit shifted in a [Fibonacci LFSR][1].
If we care to write the first $2m$ bits of the output of the LFSR as a function of the $a_i$ and initial state $s_i$, we'll get a system of equations with $2m$ unknowns. Solving that system of equa... |
I am currently leaning about LFSRs.
I was told that a binary LFSR with length m has a form of $s_m=a_0s_0+a_1s_1+\ldots+a_{m-1}s_{m-1}$ are binary numbers.
$a_0\ldots a_{m-1}$ are hidden and we are given the output stream of bits $(01101010\ldots)$
How can I determine the coefficients from the given output str... |
I guess $s_m=a_0s_0+a_1s_1+\ldots+a_{m-1}s_{m-1}$ is the equation giving the next bit shifted into the state of a [Fibonacci LFSR][1].
If we care to write the first $2m$ bits of the output of the LFSR as a function of the $a_i$ and initial state $s_i$, we'll get a system of equations with $2m$ unknowns (the $a_i$ an... |
I guess $s_m=a_0s_0+a_1s_1+\ldots+a_{m-1}s_{m-1}$ is the equation giving the next bit shifted into the state of a [Fibonacci LFSR][1].
If we care to write the first $2m$ bits of the output of the LFSR as a function of the $a_i$ and initial state $s_i$, we'll get a system of equations with $2m$ unknowns (the $a_i$ an... |
> Knowing the coordinates of $R$ on [secp256k1][1] and an integer $s$, how do we validate that $s$ is the slope at the point $Q$ on secp256k1 such that $R=2Q$ ?
One way would be computing $Q=((n+1)/2)R$ by point multiplication as in [this answer][2], then computing the slope at $Q$ and comparing to $s$.
But there... |
I guess $s_m=a_0s_0+a_1s_1+\ldots+a_{m-1}s_{m-1}$ is the equation giving the next bit shifted into the state of a [Fibonacci LFSR][1].
If we care to write the first $k$ bits of the output of the LFSR as a function of the $a_i$ and initial state $s_i$, we'll get a system of $k$ equations with $2m$ unknowns (the $a_i$... |
I guess $s_m=a_0s_0+a_1s_1+\ldots+a_{m-1}s_{m-1}$ is the equation giving the next bit shifted into the state of a [Fibonacci LFSR][1].
If we care to write the first $k$ bits of the output of the LFSR as a function of the $a_i$ and initial state $s_i$, we'll get a system of $k$ equations with $2m$ unknowns (the $a_i$... |
I am studying a little bit about one-way functions from Dr Goyal's notes.
He constructs the following OWF:
Let $D=\Bbb Z_2^{n^3}$ and $R=\Bbb Z_2^{2 n}$. Given $x \in D$, $f$ interprets $x$ as a set $S$ of $n^2$ numbers, each of $n$ bits and uses deterministic PT primality test to find the first two 2 primes in ... |
This [article][1] explains the role of key blinding in Ascon. Key blinding in Ascon involves XORing the key with the capacity part after the permutation in both the initialization and finalization stages.
[![enter image description here][2]][2]
Quoting from the paper:
> we demonstrate that Ascon without key ... |
As is well known, a sigma protocol can be transformed into a NIZK protocol through a Fiat-Shamir transform.
But can the Sigma protocol be transformed into a signature of knowledge in a similar manner?
Intuitively, it seems possible, but which research studies have directly proven this issue? |
We know that A function $f:\Bbb Z_2^n \longrightarrow\Bbb Z_2^m$ is a **(strong) one-way function (OWF)**, if:
- $f$ can be computed by a PT algorithm. Equivalently, there exists a PPT algorithm that on input $x$ outputs $f(x)$, for all $x\in \Bbb Z_2^n$.
- For all PPT adversaries $A$, there exists a negligible... |
What is a non-OWF? |
As suggested by the title, I'm working on an exercise where I'm given a hash function $H$ that takes in an input string $x$. I'm supposed to construct a distinguisher that proves $H$ isn't collision-resistant. I'm given a block cipher $F$, $F^{-1}$ as well. $F$ generates outputs of length $\lambda$. The hash function $... |
In the Full-State Keyed duplex[1] (sponge construction AEAD), plaintext is absorbed into the entire state of the sponge permutation but only a portion of the output can be used else the scheme breaks (permutation state leaks, key leaks).
How is this data asymmetry in any way useful? You cannot encrypt the block of p... |
How is the Full-State Keyed duplex useful? |
The definition of a OWF involves a distribution over $x$. So the negation also involves a distribution.
"$f$ is not a OWF" means: [either $f$ is not polynomial-time, or]
there is a PPT adversary such that $\Pr[ \text{OWF}^{A}_f \Rightarrow \text{true} ]$ is nonnegligible function of the security parameter.
> My ... |
Take secp256r1 as an example, the parameter of the curve is
```
p = 0xffffffff00000001000000000000000000000000ffffffffffffffffffffffff
a = 0xffffffff00000001000000000000000000000000fffffffffffffffffffffffc
b = 0x5ac635d8aa3a93e7b3ebbd55769886bc651d06b0cc53b0f63bce3c3e27d2604b
G = (0x6b17d1f2e12c4247f8bce6e563a440... |
Could a EC public key have zero coordinate? |
> 1. Assuming that the nonce values are unique and generated according to some fixed public counter sequence that is not under the attacker's control, is the encryption scheme described above (i.e. pad the nonce to a full cipher block, prepend it to the plaintext, and encrypt the result using CBC mode with an all-zero ... |
In the [Full-State Keyed duplex][1] (sponge construction AEAD), plaintext is absorbed into the entire state of the sponge permutation but only a portion of the output can be used else the scheme breaks (permutation state leaks, key leaks).
How is this data asymmetry in any way useful? You cannot encrypt the block of... |
Let $X = \{0, 1\}^n$. Given a PRF $F : X \times X \rightarrow X$, define
$$H(k, x) = F(k,x) \oplus F(k,x \oplus 1^n).$$
I *think* this is insecure, since $H(k, x) = H(k, \bar{x})$ for all $x \in X$, where the bar notation denotes the bitwise not.
However, I was able to come up with the following innocent-looki... |
I'm designing a hash function which uses a double-tree construction and a compression function $c(s,A,B,C,a)$ ($s$ and $a$ may be omitted when there's only one of them) where
- $s$ is a set of three key-dependent 8×8 S-boxes
- $A$, $B$, and $C$ are 32-byte blocks; $C$ may be empty, in which case it is omitted
-... |
We know that A function $f:\Bbb Z_2^n \longrightarrow\Bbb Z_2^m$ is a **(strong) one-way function (OWF)**, if:
- $f$ can be computed by a PT algorithm. Equivalently, there exists a PPT algorithm that on input $x$ outputs $f(x)$, for all $x\in \Bbb Z_2^n$.
- For all PPT adversaries $A$, there exists a negligible... |
We know that A function $f:\Bbb Z_2^n \longrightarrow\Bbb Z_2^m$ is a **(strong) one-way function (OWF)**, if:
- $f$ can be computed by a PT algorithm. Equivalently, there exists a PPT algorithm that on input $x$ outputs $f(x)$, for all $x\in \Bbb Z_2^n$.
- For all PPT adversaries $A$, there exists a negligible... |
I am a little unsure exactly what you mean.
If I am correct; you are stating that an interactive identification scheme can be turned into a non-interactive signature scheme using the Fiat-Shamir Transformation?
If that is the case: I agree.
Further you ask if a sigma protocol be transformed into a signature of k... |
> In the Full-State Keyed duplex (sponge construction AEAD), plaintext is absorbed into the entire state of the sponge permutation but only a portion of the output can be used else the scheme breaks (permutation state leaks, key leaks).
This is an interesting observation. Indeed, revealing the full state of the spon... |
> In the Full-State Keyed duplex (sponge construction AEAD), plaintext is absorbed into the entire state of the sponge permutation but only a portion of the output can be used else the scheme breaks (permutation state leaks, key leaks).
This is an interesting observation. Indeed, revealing the full state of the spon... |
Hi I would like to ask a question when reading the proof of lemma 4 (https://eprint.iacr.org/2011/277.pdf in page 10) of the BGV paper: <br/>
The assumption is: [![assumption][1]][1]
[1]: https://i.stack.imgur.com/Nkc83.png <br/>
And the inequality: [![inequality][1]][1]
[1]: https://i.stack.imgur.com/Q... |
Hi I would like to ask a question when reading the proof of lemma 4 (https://eprint.iacr.org/2011/277.pdf in page 10) of the BGV paper: <br/>
The assumption is: [![assumption][1]][1]
[1]: https://i.stack.imgur.com/Nkc83.png <br/>
And the inequality: [![inequality][1]][1]
[1]: https://i.stack.imgur.com/Q... |
I would like to ask a question that arose when reading the proof of lemma 4 on page 10 of [this][1] BGV paper:
The assumption is:
[![assumption][2]][2]
And the inequality:
[![inequality][3]][3]
So it seems that
$$ \sum_{j=1}^{n} \parallel c'[j]-(p/q) \cdot c[j] \parallel \cdot \parallel s[j] \para... |
There are a lot of oblivious transfer algorithm. What is the best? It would be good if it were malicious secure, but that is not necessary, if this make protocol very difficult/slow. This protocol should be not very difficult, but the most important it should be fast and has low communication complexity.
|
What is best $1$ out $2$ oblivious transfer? |
> I don't know if this is a point that $G$ could generate.
Yes it is.
As stated in the question, this point satisfies the equation of [secp256r1][1]. That defines a group of prime order $n$ (given in the linked reference). That is, there are $n$ elements in the group formed by the point at infinity $\mathcal O$ a... |
I'm working with the secp256k1 elliptic curve and have point doubling and point addition formulas for this curve.
If a point is given $Q_x$ and $Q_y$
```
Qx = 112711660439710606056748659173929673102114977341539408544630613555209775888121
Qy = 255830279805708836916569058774019764064488682548162950699198889605415... |
> I don't know if this is a point that $G$ could generate.
Yes it is.
As stated in the question, this point satisfies the equation of [secp256r1][1]. That defines a group of prime order $n$ (given in the linked reference). That is, there are $n$ elements in the group formed by the point at infinity $\mathcal O$ a... |
if you want to convert prf to oprf, maybe like this?
[![enter image description here][1]][1]
[1]: https://i.stack.imgur.com/t8ZqM.png
https://scholar.archive.org/work/uf6brybixrfozltlltnehtem7y/access/wayback/https://dl.acm.org/doi/pdf/10.1145/3503045
https://www.iacr.org/archive/tcc2009/54440575/54440575... |
The calculation/formula i use in deriving a public key from the private key without importing any module in python3 script involves the following steps:
1. Define the parameters of the secp256k1 elliptic curve:
```python3
p = 0xFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFEFFFFFC2F
a = 0
b = 7
Gx = 0x... |
Can the public key be generated from the private key? |
The calculation/formula i use in deriving a public key from the private key without importing any module in python3 script involves the following steps:
1. Define the parameters of the secp256k1 elliptic curve:
```python3
p = 0xFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFEFFFFFC2F
a = 0
b = 7
Gx = 0x... |
The calculation/formula i use in deriving a public key from the private key without importing any module in python3 script involves the following steps:
1. Define the parameters of the secp256k1 elliptic curve:
```python3
p = 0xFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFEFFFFFC2F
a = 0
b = 7
Gx = 0x... |
Can the public key be derived from the private key? |
I'm trying to understand how the safe primes numbers are used in Diffie–Hellman key exchange. According to wiki:
> The order of G should have a large prime factor to prevent use of the
> Pohlig–Hellman algorithm to obtain a or b. For this reason, a Sophie
> Germain prime q is sometimes used to calculate p = 2q +... |
I'm trying to understand how the safe primes numbers are used in Diffie–Hellman key exchange. According to wiki:
> The order of G should have a large prime factor to prevent use of the
> Pohlig–Hellman algorithm to obtain a or b. For this reason, a Sophie
> Germain prime q is sometimes used to calculate p = 2q +... |
Well, first off, when you have a safe prime $p$, then all the values between $1$ and $p-1$ fall into four categories:
- Values $g$ that have the order $p-1$; these values generate all values between $1$ and $p-1$, that is, $g^x = a \pmod p$ has a solution $x$ for all values $1 \le e < p$. These values of $g$ are no... |
Well, first off, when you have a safe prime $p > 5$, then all the values between $1$ and $p-1$ fall into four categories:
- Values $g$ that have the order $p-1$; these values generate all values between $1$ and $p-1$, that is, $g^x = a \pmod p$ has a solution $x$ for all values $1 \le e < p$. These values of $g$ ar... |
> I don't know if this is a point that $G$ could generate.
Yes it is.
As stated in the question, this point satisfies the equation of [secp256r1][1]. That defines a group of prime order $n$ (given in the linked reference). That is, there are $n$ elements in the group formed by the point at infinity $\mathcal O$ a... |
As we all know, nonce reuse in AES/GCM can easily be catastrophic.
However, I'm wondering if the same risks are present if an adversary has access to:
1. Ciphertext and corresponding MAC of one message
2. Small amount of plaintexts and MACs of different messages
using the same *(key, nonce)* tuple.
Would... |
For the inverse you need to solve the discrete logarithm problem; namely, given $P = [x]G$ over a prime curve $E$ wit the generator $G$, find $x$.
There are many works for speeding the discrete logarithm, currently best achievement are performed with [Pollard's Rho][1] and this is based on the on the [Floyd's cycle... |
> However, I'm wondering if the same risks are present if an adversary has access to:
> Ciphertext and corresponding MAC of one message
> Small amount of plaintexts and MACs of different messages
If there is a 16-byte aligned block in the second message that the attacker has no information about (that is, all $2... |
For the inverse you need to solve the discrete logarithm problem; namely, given $P = [x]G$ over a prime curve $E$ wit the generator $G$, find $x$.
There are many works for speeding the discrete logarithm, currently best achievement are performed with [Pollard's Rho][1] and this is based on the on the [Floyd's cycle... |
As stated in the [Ascon specification][1], the keyed initialisation and finalisation help prevent key recovery/universal forgery when the internal state is recovered by an attacker during associated data/plaintext/ciphertext processing. For example, via side-channel attacks or significant nonce reuse.
The authors us... |
knowing the coordinates of $R$ on secp256k1 and an integer $s$, how do we validate that $s$ is the slope at the point $Q$ on secp256k1 such that $R=2Q$ ? |
For the inverse you need to solve the discrete logarithm problem; namely, given $P = [x]G$ over a prime curve $E$ with the generator $G$, find $x$.
There are many works for speeding the discrete logarithm, currently best achievement are performed with [Pollard's Rho][1] and this is based on the on the [Floyd's cycl... |
A sponge has by definition 'wasted' operations (the part of the state which always remains private but goes through all the ops of the permutation).
In return for that waste you get a MAC at the end - and it is actually said that it's for free.
But the ops wasted on the hidden state cannot compete with something ... |
Are sponges inherently inefficient vs. other constructions? |
A sponge has by definition 'wasted' operations (the part of the state which always remains private but goes through all the ops of the permutation).
In return for that waste you get a MAC at the end - and it is actually said that it's for free.
But the ops wasted on the hidden state cannot compete with something ... |
I'm confused about something that makes AES GCM great.
It uses MAC to sign data it encrypts. I also uses nonce.
But lets say I encrypt data in software A. Software A produces a ciphertext and a tag as shown here : https://pycryptodome.readthedocs.io/en/latest/src/cipher/aes.html
But when I want to decrypt the c... |
Is it possible to use two different engine to encrypt/decrypt data with AES GCM? |
A sponge has by definition 'wasted' operations (the part of the state which always remains private but goes through all the ops of the permutation).
In return for that waste you get a MAC at the end - and it is actually said that it's for free.
But the ops wasted on the hidden state cannot compete with something ... |
Are sponges inherently inefficient when compared to other constructions? |
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