Tagged Questions

An authenticated encryption mode of operation for a block cipher, based on the CTR mode and the OMAC/CMAC MAC algorithm.

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4
votes
1answer
59 views

Authenticating Very Short (Sub-Block) Data

If I'm encrypting very short/small data - like an int or a long (32 or 64 bits), does it make any sense to authenticate the ciphertext, when using an "online" mode of operation (like EAX)? ...
1
vote
1answer
51 views

EAX: OMAC and CMAC

OMAC is specified as the underlying algorithm to provide authentication within the EAX authenticated encryption (with associated data). Would that be OMAC1 or OMAC2? If it is OMAC1, does that mean it ...
2
votes
1answer
108 views

Is this EAX extension weakening the (provable) security of EAX?

I would like to insert a key deriving function into EAX mode, in order to hamper brute-force attacks for a key-size restricted cipher (56 bits). The modification inserts an identical multi-block ...
4
votes
2answers
90 views

Is it possible to insert a key derivation function when using EAX?

I am currently investigating use of EAX mode for a dedicated application and following useful clarifications received from my previous post , to consider according to my applicable input security ...
4
votes
1answer
140 views

Does EAX use the same keys for encryption and authentication?

I am actually checking use of EAX AEAD mode, and following EAX spec review (scheme definition for my part), my question is: what about the derivation of the authentication and encryption keys? In the ...
7
votes
2answers
271 views

Is using EAX mode with a 64-bit block cipher a bad idea?

EAX mode produces an authentication tag no longer than the length of the underlying cipher's blocksize. So in the case of using Blowfish (a 64-bit block cipher) in EAX mode, the resulting tag would ...
5
votes
1answer
481 views

How to use GCM mode and associated-data properly

I'm currently migrating a project to use the bouncy castle GCM mode. I understand that using an authenticated mode removes the need for a HMAC, however I want to be sure that I'm using this mode ...
2
votes
1answer
159 views

How is the EAX-mode used in EAP-PSK (RFC 4764)?

According to the specification of RFC 4764, contents in EAP's third message and fourth message are required to be encrypted by AES-128 in EAX mode (also called protected channel). In RFC 4764, the ...
3
votes
1answer
135 views

What “Tag Length” should be used for the EAX MAC?

Since EAX is very flexible with regard to the length of the calculated MAC (what they call "tag" is the MAC value right?), and the EAX paper as well as other documentations carefully avoid suggesting ...