Multishot network coding is considered in a worstcase adversarial setting in which an omniscient adversary with unbounded computational resources may inject erroneous packets in up to t links, erase up to ρ packets, and wire-tap up to µ links, all throughout ℓ shots of a linearly-coded network. Assuming no knowledge of the underlying linear network code (in particular, the network topology and underlying linear code may be random and change with time), a coding scheme achieving zero-error communication and perfect secrecy is obtained based on linearized Reed-Solomon codes. The scheme achieves the maximum possible secret message size of ℓn ′ − 2t − ρ − µ packets for coherent communication, where n ′ is the number of outgoing links at the source, for any packet length m ≥ n ′ (largest possible range). By lifting this construction, coding schemes for non-coherent communication are obtained with information rates close to optimal for practical instances. The required field size is q m , where q > ℓ, thus q m ≈ ℓ n ′ , which is always smaller than that of a Gabidulin code tailored for ℓ shots, which would be at least 2 ℓn ′ . A Welch-Berlekamp sum-rank decoding algorithm for linearized Reed-Solomon codes is provided, having quadratic complexity in the total length n = ℓn ′ , and which can be adapted to handle not only errors, but also erasures, wiretap observations and non-coherent communication. Combined with the obtained field size, the given decoding complexity is of O(n ′4 ℓ 2 log(ℓ) 2 ) operations in F2, whereas the most efficient known decoding algorithm for a Gabidulin code has a complexity of O(n ′3.69 ℓ 3.69 log(ℓ) 2 ) operations in F2, assuming a multiplication in a finite field F costs about log(|F|) 2 operations in F2.