What is the key size of the International Data Encryption Algorithm (IDEA)?

The correct answer is B. 128 bits. The International Data Encryption Algorithm (IDEA) is a block cipher that operates on 64 bit blocks of data with a 128-bit key. The data blocks are divided into 16 smaller blocks and each has eight rounds of mathematical functions performed on it. It is used in the PGP…

Submitted by deeparc· Apr 18, 2026Cryptography

Question

Options

A64 bits
B128 bits
C160 bits
D192 bits

How the community answered

(30 responses)

B
90% (27)
C
7% (2)
D
3% (1)

Explanation

The International Data Encryption Algorithm (IDEA) is a block cipher that operates on 64 bit blocks of data with a 128-bit key. The data blocks are divided into 16 smaller blocks and each has eight rounds of mathematical functions performed on it. It is used in the PGP encryption software.

Topics

#IDEA#Symmetric Encryption#Key Size#Cryptography Basics

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