Tag Info

New answers tagged

1

Yes, and that's how it's normally done. This even applies to AEAD schemes like GCM, CCM, and EAX (which all encrypt with CTR and MAC as a separate matter with some other algorithm); with non-AEAD schemes, you have systems like CBC+HMAC in TLS, and (with stream ciphers for encryption) ChaCha20+Poly1305 (which are two completely independent algorithms). ...


2

That's a lot of questions, I'll try and answer in order. A hash or message digest alone is not secure because anybody can calculate and thus substitute a hash value. If you (correctly) add a key to the mix then you get a HMAC, which can be used. Nowadays often a HMAC is used, or an authenticated mode of authentication such as GCM, CCM (for packet ...


1

For question (1): This page gives some hints on IVs and CBC: https://defuse.ca/cbcmodeiv.htm I copy-paste the part about IVs "predictability" Chosen-Plaintext Attacks Randomness is not enough, though. IVs have to be unpredictable, too[2]. Suppose there is a CBC-mode encryption system that selects a random IV, publishes it, asks the user ...


3

It is certainly wrong to state that "MAC can only be produced with AES in CBC and CFB mode", but there seems to be a simple reason that people were inspired by these modes when thinking up possible MAC constructions: They carry along some state that incorporates information from the message while traversing the input blocks. In both modes, encrypting a block ...



Top 50 recent answers are included