Summary: The recent developments in the creation of large-scale, commercially feasible quantum computers puts both symmetric and asymmetric encryption at risk. As they assess the security of 5G and beyond, the telecommunication standards groups are now inviting recommendations that take the threat posed by quantum adversaries into account. Rocca is the first cipher designed that complies with 6G specifications. In this paper we analyze the security of Rocca against quantum adversaries. We first construct the quantum circuit of Rocca and estimate the cost of implementing Grover’s algorithm for key recovery. We also compute the cost under the NISTs MAXDEPTH restriction. We then find a differential distinguisher for 5 and 6 rounds in secret key settings and related key settings respectively. In the nonce-respecting settings, we discover that Rocca is susceptible to a quantum forging attack with a complexity of \(\mathcal{O}(2^{75})\) in the \(Q2\) settings, i.e., if the adversary is given access to quantum superposition queries to the cryptographic oracle. This complexity is considerably less than the complexity of \(\mathcal{O}(2^{128})\) claimed by the authors. Thus we propose that the number of initialization rounds in Rocca can be reduced without compromising its security and the tag length should be increased to 256-bits.