EN
A completely primary ring is a ring R with identity 1 ≠ 0 whose subset of zero-divisors forms the unique maximal ideal 𝒥. We determine the structure of the group of automorphisms Aut(R) of a completely primary finite ring R of characteristic p, such that if 𝒥 is the Jacobson radical of R, then 𝒥³ = (0), 𝒥² ≠ (0), the annihilator of 𝒥 coincides with 𝒥² and $R/𝒥 ≅ {GF}(p^{r})$, the finite field of $p^{r}$ elements, for any prime p and any positive integer r.