Given a key $e = 3$ (the public exponent for RSA) and a group of numbers, say $Z_n^*$ (the multiplicative group of $n = pq$, where $p$ and $q$ are primes as requested by RSA).
I can find the decryption key: $d = e^{-1}$
Is it correct to say than any member $a$ in $Z_n^*$ has a source such that: $source = a ^ d$?
Edit: suppose we have gcd(3,phi(n)) = 1 as requested by RSA