SystemHashUtil

SystemHashUtil is a static class that generates and validates salted system-hash values used as identifiers for secure configuration retrieval. It is built on the framework-inherited SAIF.HashUtil package's SaltShaker.

Purpose

• Compute a unique, salted hash identifying the calling system (by type and name) for use as a systemHashValue with IEnvironmentService.GetSecureConfigSetting.
• Validate that a previously issued system hash has not expired.

Context

• Namespace: SAIF.Services.Common
• Assembly/package: SAIF.Framework.Security.EnvironmentApi

Public members

Member	Signature	Purpose
ComputeHash	public static string ComputeHash(SystemType type, string systemName)	Computes a salted SHA-256 hash of "{systemName}-{(int)type}" using SaltShaker. See BR-008.
ComputeHashNow	public static string ComputeHashNow(SystemType type, string systemName)	Computes the unsalted hash value on the fly; used by the Environment API's system-hash route.
Get	public static string Get(SystemType type)	Resolves the entry/executing assembly name and calls ComputeHash(type, assemblyName).
GetAssembly	public static Assembly GetAssembly()	Resolves the main entry or web application assembly, falling back through several detection strategies.
RemoveSystemHashSaltAndValidateLifetime	public static string RemoveSystemHashSaltAndValidateLifetime(string systemHashValue, int expireSeconds, int nowBufferSeconds)	Un-salts a hash to recover its embedded creation timestamp and throws SystemHashExpiredException if it falls outside the valid expiry window.

The companion public enum SystemType (same file) defines: Console, WindowsService, WebApp, Guidewire, ThickClient, Script — used to add uniqueness to the generated hash.

Behavioral notes

• ComputeHash calls new SaltShaker(DateTime.Now).SaltHash(value), embedding a creation timestamp in the salted hash for later expiry validation.
• GetAssembly tries, in order: Assembly.GetEntryAssembly(), a web-application entry-assembly resolution via HttpContext.Current.ApplicationInstance, a legacy web entry-assembly resolution via stack-frame inspection, then Assembly.GetExecutingAssembly() as a last resort.
• RemoveSystemHashSaltAndValidateLifetime throws SystemHashExpiredException (from SAIF.HashUtil) when the current time (adjusted by nowBufferSeconds) falls outside the [creation time, creation time + expireSeconds) window.

Constraints and usage notes

• No internal call sites for GetSecureConfigSetting (the method this hash is intended to support) exist within this library — SystemHashUtil is defined here for consuming applications to generate their own hash values*.
• Depends on the external, unindexed SAIF.HashUtil package for SaltShaker and SystemHashExpiredException.

Note: Statements marked with * were inferred from code structure, naming conventions, or contextual evidence where direct confirmation was not available in source artifacts. Statements marked with ** could not be confirmed; treat as unknown until verified.

Sources

• SAIF.Framework.Security.EnvironmentApi\Services.Common\SystemHashUtil.cs