IDEA cryptographic algorithm have following rounds and key size:

Concept

A symmetric block cipher is fully specified by three design parameters — its block size, its key size, and its number of identical rounds (plus any final output/half-round transformation). For the IDEA (International Data Encryption Algorithm) cipher these values are fixed by its design: a 64-bit block, a 128-bit key, and 8 full rounds followed by a final output transformation (the half-round).

Application

The question asks for the (rounds, key size) pair. From IDEA's specification the number of full rounds is 8 and the key size is 128 bits, so the matching pair is 8, 128.

Contrast with the other listed pairs

• 16, 32 — neither value matches: IDEA has 8 rounds, not 16, and its key is 128 bits, not 32.

• 32, 128 — the key size 128 is right, but 32 is not IDEA's round count.

• 16, 64 — 64 is IDEA's block size, not its key size, and 16 is not its round count.

Cross-check

A 64-bit block, a 128-bit key, and 8 rounds is the standard textbook specification of IDEA, so the (rounds, key size) pair 8, 128 is consistent.