Initial commit

src/utils/crypto.js

@@ -0,0 +1,51 @@
+/**
+ * Cryptographic Utilities
+ * 
+ * Hash functions for content deduplication and verification.
+ */
+
+import { createHash } from 'crypto';
+
+/**
+ * Generate SHA-256 hash of content
+ */
+export function sha256(content) {
+  if (typeof content !== 'string') {
+    content = JSON.stringify(content);
+  }
+  return createHash('sha256').update(content).digest('hex');
+}
+
+/**
+ * Generate content hash for metadata comparison
+ * Excludes volatile fields like server_time
+ */
+export function hashMetadata(metadata) {
+  if (!metadata) return null;
+
+  // Extract stable fields only
+  const stableFields = {
+    name: metadata.name,
+    pubkey: metadata.pubkey,
+    version: metadata.version,
+    description: metadata.description,
+    description_long: metadata.description_long,
+    contact: metadata.contact,
+    motd: metadata.motd,
+    icon_url: metadata.icon_url,
+    nuts: metadata.nuts,
+    tos_url: metadata.tos_url,
+  };
+
+  // Sort keys for consistent hashing
+  const sorted = JSON.stringify(stableFields, Object.keys(stableFields).sort());
+  return sha256(sorted);
+}
+
+/**
+ * Generate a short hash for display
+ */
+export function shortHash(content, length = 8) {
+  return sha256(content).substring(0, length);
+}
+