What is the key size in bits used by the RC2 encryption algorithm?

The RC2 encryption algorithm is designed to utilize a variable key size ranging from 1 bit to 128 bits. This flexibility allows users to select different key lengths depending on the desired level of security and performance considerations. In practice, the most commonly used key sizes for RC2 include 40 bits, 64 bits, and up to 128 bits, but the algorithm's capability extends to any size within the defined range of 1 to 128 bits. This adaptability in key size is significant for cryptographic implementations, as it allows for varying security requirements while balancing between encryption strength and processing efficiency.