# Tag Info

7

Plenty of ciphers come out of the USA from government research or selection competitions. AES and DES are examples. Indeed, the US is known from some crypto-related competitions that were/are ope to anyone and they surely will do ample of government research related to cyptology, but you need to be sure that you differ between “they selected it” and ...

5

No they did not, the internals and security levels have not been changed from the draft Keccak submission, only the padding rule has changed. The padding change is the only difference, this allows future tree hashing modes as well as the current SHAKE outputs to generate different digests given the same security parameters and message inputs. Up to 4 ...

3

The reason NIST chose one algorithm out of the five AES finalists, even though all of them were pretty well-respected (and some were, at the time, considered likely to be more secure then Rijndael) is because NIST is a standards body, and the whole point of the AES project was to find a standard algorithm. The issue with approving lots of algorithms is that ...

3

PRNGs are a difficult and hot topic. Some tests can be found here: What tests can I do to ensure my PRNG is working correctly? But they do not tell you (or others) if your PRNG is really secure. A PRNG must be build in a way, that a third party is not able to "calculate" former or upcoming PRNG output based on some random data from the PRNG.

3

NIST SP800-131A (Recommendation for Transitioning the Use of Cryptographic Algorithms and Key Lengths, 2011) §4 specifies that the RNGs from ANSI X9.31 are disallowed after 2015, but as fgrieu notes this is a 3DES-based algorithm; the NIST specification does not explicitly mention the commonly-used AES variant. NIST does however recommend (but not mandate) ...

3

X9.31-based PRNGs as used in current practice (including in the Botan library) tend to be extensions of the generator of ANSI X9.31-1998 appendix A.2.4 (which designated purpose is as a submodule of a prime generator for RSA keys). This really is the PRNG of ANSI X9.17-1985 Appendix C (which designated purpose is generating DES keys), also described in ...

3

Actually, s is in CFB mode to handle transmission channels for the encrypted data that can add or drop individual bytes. In the olden times (say, the 70's), it was common to transmit data over serial channels, for example, RS-232. These channels were not perfect, and one common error we see is that if the transmitter sent 7 bytes, the receiver might get ...

2

I don't consider the following a complete answer, but it is a start, and best I can do with my very limited knowledge. I hope someone could fix it or improve it. These type of attacks are only possible against specific implementation of higher level protocols. I will start by describing an invalid-curve attack against a specific ECDH based protocol. ...

2

Your output already includes the relevant interpretation guidelines: The minimum pass rate for each statistical test with the exception of the random excursion (variant) test is approximately = 96 for a sample size = 100 binary sequences. The minimum pass rate for the random excursion (variant) test is approximately = 67 for a sample size = 71 binary ...

2

The sect curves are curves over a binary field. From SEC 2: Recommended Elliptic Curve Domain Parameters (chapter 3): The example elliptic curve domain parameters over $\mathbb{F}_{2^m}$ have been given nicknames to enable them to be easily identified. The nicknames were chosen as follows. Each name begins with sec to denote ‘Standards for Efficient ...

2

Background When defining protocol compliant with NIST SP 800-108, you just need to pick suitable options, which work well with your protocol. If there is a need to be compatible with a specific pre-existing protocol, you may want to take a look at NIST SP 800-135Rev1, which defines application specific key derivation functions. It is notable to recognize ...

1

When NIST put together the table A.1, they accidentally used a 96 character alphabet for that last column, not a 94 character one. One way to see this is looking at the bottom most entry; they list that $log_2(b^{40}) \approx 263.4$, where $b$ is the alphabet size they used. If we solve for $b$, we get $b \approx 96.002...$.

1

Twofish and Serpent do not have any published non theoretical successful attacks (resulting in a complete break) so at this point in time they are considered secure. AES was chosen because the people making the decisions at NIST felt it made the best decisions (as far as the Rijndael spec goes) of making trade offs between security, speed, computing ...

1

It is for the 1st version of 3DES which is only using the same key three times (3DES-EDE1) Which is equivalent to DES (I think they did that so you could use 3DES to exchange with someone using DES). There are 3 different versions (or ways of using DES). EDE3 is the strongest with 3 different keys being used.

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