Blog

The most important variable in the recovery of organisms in adult patients with bacteremia is:

Which organism can have a “weakly positive” catalase reaction?

Which of the following organisms is responsible for impetigo?

What is the MIC? (yellow fluid indicates growth) image00163924061.jpg

It is vitally important to have a pure culture or isolated colonies when performing antimicrobial susceptibility testing (AST).  This may require colonies to be “subbed out” prior to setting AST.

Assume a sender and receiver use basic CBC-MAC but authenticate/accept messages of different lengths. Which of the following is a valid attack?

Which of the following is a generator of Z*11?

Assume the Diffie-Hellman protocol is run by two parties in the subgroup of Z23∗ generated by 2. (This subgroup has order 11.) If the first party chooses private exponent 3 and the second chooses private exponent 10, which of the following characterizes the execution of the protocol in this case?

What is ϕ(77)?

Say we modify CBC-MAC to incorporate a random IV. So authentication of a 1-block message m using a block cipher F and key k is done by choosing a uniform IV and outputting the tag IV,Fk(IV⊕m). Verification is done in the natural way. Say this scheme is used with an 4-byte block cipher, and an attacker sees the tag 0x01 01 01 01 05 06 07 08 on the message 0x 00 00 01 01. Which of the following will be a valid message/tag pair?