Reputation
1,290
Top tag
Next privilege 1,500 Rep.
Approve tag wiki edits
Badges
4 9
Newest
 Yearling
Impact
~31k people reached

Feb
22
answered Linear Recurrence, keystreams, and periods
Feb
22
comment Hill Cipher the point of a known plaintext attack question
@Connor Glad I could help!
Feb
22
answered Hill Cipher the point of a known plaintext attack question
Feb
22
comment Substitution-permutation network
AES is an example, one could say the most important one.
Feb
22
comment Substitution-permutation network
It's IMHO probably best understood by an example.
Feb
22
comment Substitution-permutation network
youtube.com/watch?v=mlzxpkdXP58 has a nice animation for AES as an example..
Feb
19
revised How to implement the Salsa20 hash function?
added 2 characters in body
Feb
19
comment How to implement the Salsa20 hash function?
Logical shift, and yes, & is missing
Feb
17
comment Crack RSA with additional information
In most textbooks (that I assumed the problem was from) it is.
Feb
17
answered Crack RSA with additional information
Feb
17
comment Crack RSA with additional information
You even need only one pair $e_A$ and $d_A$.
Feb
10
comment Trivium example
ecrypt.eu.org/stream/p3ciphers/trivium/trivium_p3.pdf, paragraph 2.1 specifies the output bytes, which are the $z_i$.The $t_i$ are then updated, and used as feedback bits. But the output is produced before the feedback bits. I don't have access to your book.
Feb
9
comment Trivium example
@NikolaLošić As to the first bit: the first 2 registers give $0$ as output, the last gives 1 (it's the final bit (1) and a middle one (which is 0)), so their xor equals 1. The output is the xor of three outputs, each of which is the xor of two bits from a different register.
Feb
8
comment Trivium example
I get 1110000000000000000000000000000000000000000000000000000000000000000110 (left to right is order in time).
Feb
8
comment Trivium example
The output consists of the xor of 6 bits (2 from each register). You output the xor of the update bits. I don't have the book, but I suppose $s$ is the stream of output bits?
Feb
2
comment Decrypt a message which is encrypted using XOR?
It seems that crypto.stackexchange.com/q/22710/553 has the same problem as you?
Feb
1
answered XOR cipher with three different ciphertexts and repeated key, key length known. How do I find the plaintexts?
Jan
19
comment RSA Key generation: How is multiplicative inverse computed?
Yes, it is a theorem (not too hard) that knowing $\phi(n)$ and $n$ both, we can compute $p$ and $q$. Even knowing all of $n,e$ and $d$, we can find $p$ and $q$ using a probabilistic algorithm. Just knowing $n$ and $e$ is too little info (it is assumed) to compute either $\phi(n), p, q $ or $d$.
Jan
16
comment Help converting sha256 to 32-bit stream
Note that the base64 encoding of 32 bytes will be $\lfloor\frac{32}{3}\rfloor\cdot 4 + 4 = 44$ characters, of which the last is an = sign (as we miss one byte when grouping into groups of 3 bytes).
Jan
14
comment PKI Infrastructure
Have a look at the SSL certificates your browser gets when connecting to a site over https. Any browser will show you the complete certificate. In order to really understand those you have to read up on PKCS , X509 standards, ASN1 encoding etc. It's a big area.