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Apr
12
answered Use cases for “online” authenticated encryption?
Apr
12
comment Randomness in generation of Virtual Machines from pre-built Image
It's a general security question, not a cryptography question. It might fit security.se.
Apr
9
comment Is it possible to combine true streaming with AEAD?
Splitting the message into segments and authenticating each segment separately is the standard approach.
Apr
7
comment Salsa20-GCM composition secure?
Strictly speaking GCM has been defined using a 128 bit block cipher, but it's easy to generalize it to any stream cipher that takes a nonce and it's be secure that way. But I see little reason to do so, since GCM only works well if you have specialized instructions, which are typically only available on CPUs which can also accelerate AES.
Apr
3
comment How to encypt/decrypt messages after ECDH key agreement
Why did you tag this with PQ-crypto? Diffie-Hellman is not PQ secure, neither on finite fields, not on elliptic curves.
Apr
3
revised How to encypt/decrypt messages after ECDH key agreement
edited tags
Apr
3
comment Required key size for an ideal cipher with a 32 bit block size
@fgrieu A 16 GiB lookup table could fit into RAM and should have acceptable performance. Efficient key expansion from a minimal-size key might be a bit trickier though.
Apr
2
comment Will there always be 256 collisions for the output of the MD5 hashsum function for 17-byte inputs?
@coder543 The whole bitcoin miner network computes around $2^{80}$ SHA256d hashes per year (burning several hundred million USD on hardware and electricity). While MD5 is a slightly cheaper than that, it'd still take it several trillion years to compute $2^{128}$ MD5 hashes.
Apr
2
comment Is there a need to encrypt data when send over https?
@MaartenBodewes Apparently the OP has an unusually painful voice :) "Doctor, it hurts when I do this." -- "Don't do that."
Apr
2
comment Is there a need to encrypt data when send over https?
As long as you ensure that you're talking to the correct server (typically by properly validating the server's certificate), sending passwords in plain isn't a big issue. "just by installing my certificate" nobody stops you from shouting yourself in the foot. You could have "just installed a trojan horse", same thing really.
Apr
2
comment Will there always be 256 collisions for the output of the MD5 hashsum function for 17-byte inputs?
Concerning rainbow tables 1) they're much smaller than all 17 byte inputs. 2) Probably below to 8 bytes or 13 lowercase letters. 3) Even for the target range, they typically only contain most but not all values.
Apr
2
revised Will there always be 256 collisions for the output of the MD5 hashsum function for 17-byte inputs?
edited body
Apr
2
revised Is it safe to encrypt random data using ECB mode?
added 49 characters in body
Apr
2
answered Coding of unsigned int to prevent guessing next ID
Apr
1
comment Probability of SHA256 Collisions for Certain Amount of Hashed Values
@vern You're right. I forgot the 1-exp(...) part
Apr
1
revised Probability of SHA256 Collisions for Certain Amount of Hashed Values
added 6 characters in body
Apr
1
reviewed Leave Open Cryptography system by combining a block cipher and a stream cipher
Apr
1
reviewed Reject Is there any pattern in points on EC?
Apr
1
answered Probability of SHA256 Collisions for Certain Amount of Hashed Values
Apr
1
revised Is it safe to encrypt random data using ECB mode?
added 32 characters in body