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docs/security.md

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+# Obsero Security Model
+
+Obsero ensures resilience and integrity through multiple layers of protection.
+
+## Threats Addressed
+
+- Proof forgery: ECDSA signature validation
+- Data tampering: Immutable hashing
+- Spam attacks: Possible stake or fee mechanism
+- Replay attacks: Timestamp uniqueness
+
+## Trust Model
+
+- Each observation is individually signed.
+- Trust shifts from the observer to cryptographic proofs.
+- Full auditability through IPFS and blockchain.