Select one answer that is most appropriate. Partial credits may be given.

a$.$

To generate a hash value from a given input, break the input into a sequence of blocks so that the size of each block is the length of the desired hash value, with necessary padding to the last block.

b$.$

Compress each block or encrypt each block using the block itself as a key for encryption, and then use cipher block chaining to chain all the blocks and produce a hash value.

c$.$

SHA$-512$ uses block compression and Whirlpool uses an AES$-$like block cipher.

d$.$

All of the above.

e$.$

SHA$-512$ block compression needs to be reversible.

f$.$

None of the above.

g$.$

Both a and b$.$

h$.$

Both b and c$.$