Questions tagged [backdoors]
A backdoor in a cryptosystem or algorithm allows someone to obtain access to the decrypted data, without the need for the key/password that was used to encrypt the data.
14
questions
162
votes
4
answers
54k
views
Should we trust the NIST-recommended ECC parameters?
Recent articles in the media, based upon Snowden documents, have suggested that the NSA has actively tried to enable surveillance by embedding weaknesses in commercially-deployed technology -- ...
- 36.4k
23
votes
2
answers
7k
views
Is there a feasible method by which NIST ECC curves over prime fields could be intentionally rigged?
The NIST elliptic curves P-192, P-224, P-256, P-384, and P-521, prescribed in FIPS 186-4 appendix D.1.2, are generated according to a well defined process, but using an arbitrary random-looking seed ...
- 141k
52
votes
6
answers
18k
views
Who uses Dual_EC_DRBG?
Recent news articles have suggested that the NSA may be involved in trying to influence the cryptography in public standards or commercially deployed software, to enable the NSA to decrypt the ...
- 36.4k
39
votes
1
answer
31k
views
Explaining weakness of Dual EC DRBG to wider audience?
I have an audience of senior (non-technical) executives and senior technical people who are taking the backdoor in Dual_EC_DRBG and considering it as a weakness of Elliptic curves in general. I can ...
- 1,697
14
votes
0
answers
893
views
The backdoor of Telegram on Diffie-Hellman Key Exchange and possibly other examples?
Diffie-Hellman Key-Exchange (DHKE) should be used carefully during the end-to-end encryption. A man-in-the-middle (MITM) attack is possible.
Standard DHKE
The simple protocol on the multiplicative ...
- 48.5k
17
votes
5
answers
1k
views
Could one construct a cipher that is secure for friendly parties to use but insecure for hostile parties?
Consider the situation of a nation state (Blue) at war with another nation state (Red). Blue wants to deploy a secure cipher that blue currently can not break, but they are considered that Red could ...
- 2,276
17
votes
3
answers
3k
views
Information about RSA key pair generation with backdoor?
Someone posted an article on Reddit a few days ago, and I haven't found much about it except for links back to the same page.
And for a brief summary, essentially, it's possible to introduce a ...
- 2,389
14
votes
3
answers
1k
views
What is the best way to put a backdoor in an encryption system?
How can you put a backdoor into an encryption algorithm? Are there any techniques that can be used to reduce the time it takes to break a key?
I am looking for practical examples encryption schemes ...
- 141
4
votes
2
answers
637
views
Why does a non-prime DH modulus creates a "NOBUS" backdoor
can't we do a nobus backdoor with DH modulus prime? Some have argued that with a prime modulus you can just get the order by doing p-1 and then factor it, thus it is easy to reverse. I argue that this ...
- 1,535
3
votes
1
answer
668
views
Proving Non-Existence of ECC Backdoors
In light of the NIST Dual EC DRBG scandal, I was intrigued by a NIST slide (slide 9) that said the two points P and Q can be chosen so that the chooser can prove they don't have a backdoor. This ...
- 131
2
votes
1
answer
915
views
Hide a weakness in ECC by choosing the prime or one of the curve coefficients
Suppose you are given a value $c$. Can you find a prime $p$ and an integer $b$ such that the elliptic curve
$$E: y^2 \equiv x^3 -3x + b \pmod p$$
is cryptographically weak? You need to choose $p,b$...
- 36.4k
7
votes
1
answer
1k
views
Does the backdoor in Dual_EC_DRBG work like that?
From what I read, the backdoor in Dual_EC_DRBG operates by using related $P$ and $Q$ points.
Did I understand the idea correctly?
Dual_EC_DRBG works by multiplying the $P$ point with the seed ...
- 835
6
votes
2
answers
447
views
Do test vectors ensure a cipher is free of backdoors?
If a cipher implementation passes unit tests using test vectors from some trusted source (these for AES, for example), then can we say that it is fully conforming to the specification, and must have ...
user9070
5
votes
1
answer
343
views
When is an asymmetric scheme considered broken?
Does the following quote imply that valid encrypted data can be created and decrypted by someone other than the owner of a private key:
An asymmetric encryption scheme is considered to be broken if ...
- 2,631