1,363 reputation
518
bio website
location Saarbrücken, Germany
age 27
visits member for 3 years, 1 month
seen 2 hours ago

May
21
comment Prefix property for variable length pseudo-random generators
$m_0$ and $m_1$ certainly still have to have the same length. Check Definition 3.8. With messages of different length, the security definition becomes meaningless.
May
15
reviewed Reject suggested edit on Is it possible to construct a secure block cipher of size $2n$ given a secure block cipher of size $n$?
May
11
comment The advantages of Merkle Signature and One time Signature
Of course it does: Only a single message can ever be securely signed under the public key of an OTS. In contrast, many messages can be signed under the public key of the Merkle scheme without compromising security.
May
9
reviewed Approve suggested edit on Cryptographically secure keyed rolling hash function
May
6
comment Is G is a secure PRG?
You should specify what F is (I assume a pseudorandom function) and where k comes from.
May
6
revised Is G is a secure PRG?
added 26 characters in body; edited tags
May
4
comment Block cipher encryption of decryption with the same key
It depends on what you mean by "encrypt with a blockcipher". If you mean using a blockcipher in a secure mode of operation, then no, the probability of this happening will be negligible.
May
3
reviewed Leave Closed Is it true, that non-military cryptography appeared in 50's and 60's only thanks to leaks from the NSA?
May
3
comment PRF and hash functions
No, hash functions are only modeled as random oracles for proofs in the random oracle model. If we work in the standard model, a hash function is only assumed to be collision resistant. The key of a hash function stems from a technicality of defining collision resistance. The problem is that it is (almost) impossible to define collision resistance for a single function. Therefore collision resistance is defined for a function family, and the key is required to select a member of that family.
May
2
reviewed Leave Open PRF and hash functions
May
1
answered PRF and hash functions
Apr
22
reviewed Close Is less security required for a short stream cipher than for the AES enciphering of very long messages?
Apr
22
reviewed Reject suggested edit on How secure is AES-256?
Apr
16
reviewed Leave Open How can I convert numbers into prime numbers?
Apr
16
reviewed Leave Open Exchanging Keyspace and Message space in PRF
Apr
15
comment What is a 'secret key factory'? What precisely is it doing?
This question appears to be off-topic because it is about the inner workings of a particular java library. But to answer your question: What you are seeing is the Object ID being printed because you tried to print an object to the standard output. Check the documentation docs.oracle.com/javase/7/docs/api/javax/crypto/spec/… what you are looking for is probably the output of the getEncoded() method.
Apr
7
reviewed Looks OK Should we MAC-then-encrypt or encrypt-then-MAC?
Apr
7
reviewed Looks OK Should we MAC-then-encrypt or encrypt-then-MAC?
Apr
7
reviewed Leave Open Compression step of PGP
Apr
7
reviewed Leave Open What is h in this RSA variant?