would be impossible. SECURITY ISSUES IN STORAGE NETWORK PROCESSING Security concerns are a high priority for SNP designers. Data that is in transit to and from a storage device must be protected at different levels from unauthorized attempts by third parties who may try to intercept parts of SNP traffic or from attacks that are likely to occur if a malicious insider such as a disgruntled employee or an outsider such as an attacker who, acting from outside, manages to hack his or her way inside the IP network. File-level security is influenced by how operating systems grant access to individual files. Storage devices, however, work with block-level I/O operations, which are a completely different story. We discuss security processors and all the required functionality for confidentiality, authentica- tion, integrity, nonrepudiation, and controlled access in Chapter 17, "Security Coprocessors." Here we only mention some critical issues that make the security-processing context relevant to storage network processing. A judiciously chosen mix of cryptographic functions is needed inside all SAN devices (and in legacy NAS systems). A manageable and scalable security architecture is also critical. The phrase "judiciously chosen" is important because performance can be penalized if the computation-heavy cryptographic operations are not delegated to specialized hardware that can process data at line speeds. In other words, if the SNP security is overburdened, storage access performance will inevitably suf- fer. If the SNP is underprotected, the assumed risk may be quite significant. The security function must be physically distributed at endpoints or in gateways. This implies that a complete corporate information security policy must be in place. This topic goes way beyond our discussion here, but session-ar packet-level flexible authentication and access controls must also be in place. This will help ensure that stored data or data in transit can only be accessed by authorized parties. At the same time, it also prevents 