Sophie Germain Counter Mode
A new mode called Sophie Germain Counter Mode (SGCM) has been proposed as a variant of the Galois/Counter Mode of operation for block ciphers. Instead of the binary field GF(2128), it uses modular arithmetic in GF(p) where p is a safe prime 2128 + 12451 with corresponding Sophie Germain prime p − 1/2 = 2127 + 6225.
Source: Wikipedia — Sophie Germain Counter Mode (CC BY-SA 4.0)