BTW: common usage nowadays is that a "safe prime" is a prime $p$ where $(p-1)/2$ is also prime (also known as a Sophie Germain prime). It used to have other meanings associated with it as well; however it's been a while since I've heard those other meanings used. Using the term now with a meaning other than what is common is likely to confuse people. If you need to use a different meaning, I'd suggest using different terminology.