Cryptography, Cybersecurity.
ciphertext is computed from a message of M as C=M^e (mod N), and is decrypted with M=C^d (mod N). We compute the the private exponent (d) from the inverse of the public exponent (e) modulus PHI, and where PHI is (p-1)*(q-1). If we can determine p and q, we can compute PHI. Anything below a 738-bit