Tagged Questions

3
votes
2answers
122 views

RSA digital signature vs authenticated cipher

I want to provide both confidentiality and integrity for data at rest (many large files stored on disk). I plan to encrypt the data using AES, which will cover the confidentiality requirement. So ...
3
votes
3answers
134 views

What is the difference between a HMAC and a hash of data?

On a recent question it became apparent that there's a significant difference between an HMAC of input data and a hash of input data. What exactly is the difference between an HMAC and a hash of a ...
-2
votes
1answer
60 views

Cryptographic Primitive Method

Is there any cryptographic primitive bijective (one-to-one and onto) function for creating cryptographic tools like symmetric encryption/decryption, Hash code generator, MAC, HMAC and Random number ...
0
votes
0answers
50 views

why these specific values used to initialize ipad & opad in HMAC [duplicate]

Possible Duplicate: What do the magic numbers 0x5c and 0x36 in the opad/ipad calc in HMAC do? I'm reading the book Network Security Essentials written by William Stallings. in this book,in ...
13
votes
2answers
532 views

What do the magic numbers 0x5c and 0x36 in the opad/ipad calc in HMAC do?

Wikipedia lists the following pseudocode for HMAC: ...
9
votes
1answer
184 views

Which MACs can be converted into a secure unkeyed hash function?

It is known that setting the secret key to a fixed, public value does not make MACs like CBC-MAC or GMAC into secure unkeyed cryptographic hash functions that could be used - for instance - for ...
3
votes
1answer
185 views

Memory-hard operations in work-factor hash functions

I'm playing around with work-factor hash functions, and I'm looking for a memory-hard operation to make it resistant to GPU / parallel hardware attacks. I considered a very large (i.e. 64K) s-box that ...
3
votes
1answer
122 views

DIfferent inner and outer hash functions for NIST Recommended HMAC?

The NIST recommended HMAC uses $$\operatorname{HMAC}_k(text) = H_\mathrm{out}( (k \oplus \mathrm{opad}) \operatorname\| H_\mathrm{in}((k \oplus \mathrm{ipad}) \operatorname\| text) )$$ Is it ...