RC5 is a family of cryptographic algorithms invented by Ronald Rivest in 1994. It is a block cipher of variable block length and encrypts through integer addition, the application of a bit-wise Exclusive Or, and variable rotations.
The key size and number of rounds are also variable. Typical block sizes are 32, 64, or 128 bits.
The number of rounds can range from 0 to 255 and the key size can range from 0 to 2048 bits. RC5 was patented by RSA Data Security in 1997.