Cryptosecurity, Digital Signatures, Asymmetric Cryptography, Hash Function, Secure Communication.
Choose a public key e such that 1 < e < phi(n) and gcd(e, phi(n)) = 1. Compute the private key d such that d * e ≡ 1 (mod phi(n)). Signing: Compute the message digest H(m) using a cryptographic hash function. Compute the signature s = H(m)^d mod n. Send the message and signature to the recipient.