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1d
revised How to generate many passwords from one passphrase, so that knowledge of one password does not compromise the others?
improved clarity by introducing the approach earlier on
1d
answered How to generate many passwords from one passphrase, so that knowledge of one password does not compromise the others?
Apr
14
comment Is Threefish the only cipher with 1024 bits of security?
VME (Virtual Matrix Encryption) [meganet.com] provides patented (US6219421) 1 million bit encryption. However, this is just the key size, and it most likely does not mean that the algorithm is $2^{1048320}$ times harder to break than AES.
Apr
9
comment Space needed to store an RSA private key
If popular algorithms for generation of p and q and selection of e are used, thanks to static bits, even little less than 4096 bits will suffice.
Apr
7
comment Key size limitations due to software compatibility?
In addition to software compatibility issues, you may expect performance issues (i.e. software executes very slowly) if you generate or use 8192 bit or 16384 bit keys.
Mar
31
comment random access stream cipher
XTS is often a pretty good solution for whole disk encryption. It is indeed possible to detect with XTS if a block returns to one of its previous values. Still, it is significantly better if attacker has chance to compare against previous snapshots than CTR. However, the original question is about database engine, which is similar but not the same problem than full disk encryption.
Mar
28
awarded  Nice Answer
Mar
2
revised Key derivation using the main AES encryption key and some plain text
added mention of password-based key derivation and authentication
Mar
2
answered Key derivation using the main AES encryption key and some plain text
Mar
1
answered SIV - Synthetic IV - S2V Construction? Benefits over a MAC or Hash?
Feb
29
revised When we turn Random shuffle to Pseudorandom Shuffle
mention ideal dice as non-binary entropy source
Feb
29
answered When we turn Random shuffle to Pseudorandom Shuffle
Feb
29
comment When we turn Random shuffle to Pseudorandom Shuffle
user153465: You may need to first understand how computers represent values between 0 and 1. One of most common ways is IEE floating point format. Once you understand the representation of floating point value used by your device then you may start thinking about conversion between bit sequence output by PRNG and floating point number. Note: To avoid small bias in number format conversions between floats and indexes, it is preferable to tweak the algorithm to work with fixed length bit sequence rather than a random number between 0 and 1.
Feb
16
answered Homomorphism and Zero Knowledge in FIPS 140-2 compliant systems
Feb
15
reviewed Approve What happens to NORX if the same (key, nonce, header data) triple is reused
Feb
8
comment How many RSA keys before a collision?
Of course it is good thing to answer. Just make sure the answer is correct. Compare your answer against, e.g., crypto.stackexchange.com/a/3044/4982 and notice that the brute force estimate 2^{2048} is incorrect and not very useful. BTW, to get started with the site see, e.g., crypto.stackexchange.com/tour. Also, if you want to give good and useful answers, the best place to start is New & Unanswered. [Disclaimer: I'm not affiliated with the site except I've answered a few questions now and then.]
Feb
8
awarded  Informed
Feb
8
comment How many RSA keys before a collision?
New people are good to have here. The negative score is because your answer has problems. Specifically, it has three problems: 1. it answers old question, which already has been addressed a long time ago; 2. it does not add useful information over the previously written excellent answer by CodesInChaos; 3. Your estimate of work in brute force attacking RSA is incorrect. It is true that current RSA is 2048, making the problem even smaller than according to computation with RSA 1024, but the computation by CodesInChaos clearly pointed out that it was not the problem back then either.
Feb
7
awarded  Yearling
Feb
5
comment NIST HMAC Test vectors
Good answer. The NIST CAVP test vectors are based on values they have chosen to be generated. These four values chosen are example. It is not feasible to have all the possible values in the test vectors so they need to pick some. However, when a cryptographic product is validated (in Cryptographic Algorithm Validation Program, such as for FIPS 140-2), it is possible to select specific key sizes, which will be tested.