What is the size of the keyspace for a double transposition cipher with m * n matrix? Justify your answer.

2. Create a view named Top10PaidInvoices that returns three columns for each vendor: VendorName, LastInvoice (the most recent invoice date), and SumOfInvoices (the sum of the InvoiceTotal column). Return only the 10 vendors with the largest SumOfInvoices and include only paid invoices.

We know that a digital signature is for the purpose of ensuring data integrity and authenticity. a) Checksum adds all the bits of the message (or blocks), is checksum a good way to construct a digital signature scheme? How about a hash function, i.e, Sign(M)= h(M)?b) If we use a hash to generate a signature in a more complicated way as follows Sign(k,m) = σ = h(k) XOR m XOR h(m), and m, σ will be sent along. Would this be a secure signature? Briefly explain. please do not use chegg or ai tool like chat gpt please

Find out what risks are involved with the various authentication techniques and suggest a way to deal with the following situation.Bob uses a cryptographic hash function to check a password against a cache of other hashes.Bob performs a cryptographic hash on a password and checks it against a database of previously double-hashed passwords.

This question concerns block cipher modes. We will use a simple affine cipher, which can be expressed in C as follows. char cipher(unsigned char block, char key) { return (key+11"block)%256; } The inverse of this cipher is shown below. char inv_cipher(unsigned char block, char key) { // 163 is the inverse of 11 mod 256 return (163*(block-key+256))%256; } Note that the block size is 8 bits, which is one byte (and one ASCII character). We will work with the fixed key 0x08. We now decrypt various ciphertexts using modes for this cipher. In every case in which the mode requires an IV, the IV will be OXAA. In the case of CTR mode, we use a (nonce || counter) arrangement in which the nonce is the left 5 bits of OXAA and the counter is a 3 bit counter that begins at 0. In all of the problems given below, one character is one block. Each character of the plaintext should be regarded as its corresponding ASCII code. The ciphertext is given in hexadecimal. a) Decrypt the ciphertext "303…

Is there a certain number of linked lists that are always included inside a hash table of size m? To save my life, please explain what the purpose of a hash function is since I have not the faintest clue. Provide an example to support your idea.

What makes a Key Derivation Function unique in comparison to other families of secure hash functions that have been explored (for example, the SHA family of algorithms)? Provide as much information as you possibly can if you want to be sure that your message is comprehended by the intended audience.

In simple uniform hashing, each key is assumed to have equal probability to map to any of the hashes in a given table of size m. Given an open-address table of size 100 and 2 random keys, what is the probability that they hash to the same value? What is the probability that they hash to different values?   PLEASE give me a written paragraph answer

Strings of undefined length are used as keys to access a hash table. Report the C implementation of a proper hash function. Specify and explain (in plain English) how to select the algorithm and how to avoid overflows during the computation of the hash function. Motivate all choices.

Find out what risks are involved with the various authentication techniques and suggest a way to deal with the following situation.Bob uses a cryptographic hash function to check a password against a cache of other hashes.Bob performs a cryptographic hash on a password and checks it against a database of previously double-hashed passwords.