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Apr
27
comment How to use OpenSSL command line utility to encrypt data with encrypted key from public key?
I am curious: is there a reason anyone would use that specific format for anything other than educational purposes, rather than in a standard format such as PKCS12 ("openssl pkcs12 ...") or S/MIME ("openssl smime ...") or the OpenPGP format ("gpg --output doc.gpg --encrypt --recipient someone@example.org doc.txt" and decoded by "gpg --output doc_copy.txt --decrypt doc.gpg")?
Apr
8
comment What problems with “random” data would cause this result from Ent?
+1: I agree that this chi squared test is detecting certain byte values occurring more often than one expects from true random data, a pattern overlooked by other tests. Accidentally discovered a random number generator? It's possible: The bug may exercise 2 or more of each core's oscillator plus the RTC oscillator. Two hardware oscillators are a key component in many true hardware random number generators. See US5117380 A (1992); Jun and Kocher "The Intel random number generator" (1999), Baudet et. al. "On the security of oscillator-based random number generators" (2009), etc.
Apr
7
answered What asymmetric key exchange algorithms are known besides DH?
Apr
6
comment Are all self-synchronizing cryptosystems necessarily self-synchronizing stream ciphers?
@otus: These "self-synchronizing ciphers" you mention -- can you name even one that is not effectively a "self-synchronizing stream cipher"? I would be very interested in any such (non-stream) self-synchronizing cipher, even if it required me to know exactly where the dropped byte(s) should have been. On the other hand, perhaps no such cipher is possible? Either way, I look forward to learning something I didn't know before.
Apr
2
comment Can error correcting codes be used to guess this plaintext?
Case (b) reminds me of deniable encryption algorithms.
Apr
2
awarded  Revival
Mar
31
comment random access stream cipher
My understanding is that the XTS mode and CTR mode (and all other popular whole-disk encryption modes) does "encrypting and decrypting the same location twice, with the same key." when writing to the disk. Are you seriously saying that all of them are doing it wrong?
Mar
31
comment A self-decrypting block-cipher
This reciprocal cipher reminds me a lot of the (usually not reciprocal) "single-key Even-Mansour cipher".
Mar
31
asked Are all self-synchronizing cryptosystems necessarily self-synchronizing stream ciphers?
Mar
30
revised How should I implement a secure recovery of encryption?
add "host-proof" tag
Mar
26
revised Finding sum of two encrypted numbers
add "homomorphic-encryption" tag
Mar
26
answered Key length requirement in a simple XOR implementation
Mar
21
comment Is regular CTR mode vulnerable to any attacks?
The "CTR", as described in the Wikipedia: block cipher mode of operation article, is a mode of operation that is used with a block cipher, often AES. That CTR is not a cipher in itself. Are you maybe referring to some other CTR? Which one?
Mar
21
answered How secure is a client-side javascript encrypter?
Mar
20
comment Is regular CTR mode vulnerable to any attacks?
I don't know of any way to use AES without also using some block cipher mode of operation. AES256 is often used with CTR. So your question doesn't make sense to me, it's like asking "Which is better, a truck with a diesel engine or a truck with 4 wheels?", when most trucks have both. Did you maybe mean to ask "Which is better, XTS or CTR to encrypt a drive?"?
Feb
23
comment Why does rsyncrypto require a public key during decryption?
@MaartenBodewes: While "Don't use security protocols that aren't even well described" is, in general, good advice, I don't see how it is relevant to this question about rsyncrypto, which is fairly well described on the Rsyncrypto Algorithm page.
Feb
23
comment How to make a “zero knowledge” cache/key-value store
When I derive a key from the password, I prefer to use a key-derivation function (KDF) rather than a HMAC.
Feb
23
comment How to make a “zero knowledge” cache/key-value store
This sounds like it could be very useful, perhaps as part of an InterPlanetary File System (IPFS). I look forward to good answers.
Feb
23
revised How to make a “zero knowledge” cache/key-value store
I think the "host-proof" tag is more relevant than the "aes" tag.
Feb
20
answered How can I make my cipher show the avalanche effect?