What is the maximum key size for the RC5 algorithm?

The correct answer is D. 2040 bits. RC5 is a symmetric block cipher designed by Ron Rivest in 1994. It is highly parameterized, with three configurable values: word size (16, 32, or 64 bits), number of rounds (0–255), and key size (0–2040 bits). The maximum key length of 2040 bits makes RC5 one of the most flexible

Submitted by anna_se· Apr 18, 2026Cryptography

Question

Options

A128 bits
B256 bits
C1024 bits
D2040 bits

How the community answered

(37 responses)

A
3% (1)
B
8% (3)
C
3% (1)
D
86% (32)

Explanation

RC5 is a symmetric block cipher designed by Ron Rivest in 1994. It is highly parameterized, with three configurable values: word size (16, 32, or 64 bits), number of rounds (0–255), and key size (0–2040 bits). The maximum key length of 2040 bits makes RC5 one of the most flexible symmetric ciphers in terms of key size. This flexibility allows RC5 to be tuned for various security and performance needs. Despite its design elegance, RC5 has largely been superseded by AES in modern implementations.

Topics

#RC5#Key Size#Symmetric Cryptography#Block Ciphers

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