Safe prime
A kind of number
About Safe prime
A safe prime is a prime p of the form p = 2q+1 where q is also prime (q is then a Sophie Germain prime). So 5, 7, 11, 23, 47, 59, … are safe primes.
Key features
- The first few are 5, 7, 11, 23, 47, 59, 83, 107.
- Used in cryptography because of the structure of the group of units mod p.
Examples: