The Rabin Signature Scheme is a method of digital signature originally proposed by Michael O. Rabin in 1979. It was one of the first digital signature schemes proposed, and it was the first to relate the hardness of forgery directly to the problem of integer factorization. Likewise recovering the entire plaintext from the ciphertext could be proven to be as hard as factoring. Because of its simplicity and prominent role in early public key cryptography, the Rabin Signature Scheme is covered in most introductory courses on cryptography. It is existentially unforgeable in the random oracle model assuming the integer factorization problem is intractable. It provides security levels similar to that of RSA. For more information, refer to Michael Rabin's original technical report describing the algorithm. VOCAL offers a wide range of cryptographic solutions in both hardware and software form factors.