Security Model

Security Model

15+ defense layers providing enterprise-grade protection.

Defense Layers

#	Layer	Description
1	Input Validation	Bounds-checked parser, path traversal rejection, injection protection
2	Capability Sandbox	No network, isolated filesystem, approved interpreters only
3	Linux Seccomp	Kernel-level syscall filtering (blocks network, fork, mount, ptrace)
4	Windows Job Objects	Memory cap (256 MB) and process limits
5	Execution Timeout	30-second hard deadline with process kill
6	Output Size Limits	stdout: 1 MB, stderr: 256 KB
7	Ed25519 Signatures	NDA document authenticity and tamper detection
8	Merkle Integrity	SHA-256 root verification of NDA content
9	Rate Limiting	Token bucket: 20 req/sec, burst 100, per-client
10	Audit Logging	10K ring buffer, JSON/CSV export
11	Error Sanitization	Strips paths, truncates at 500 chars
12	CORS Protection	Configurable origin restrictions
13	API Key Auth	Timing-safe comparison
14	Dependency Audit	0 vulnerabilities (cargo audit)
15	CI/CD	Build + test + audit on every push/PR

Sandbox

All execution (shell_exec, execute_nda) runs in a capability-based sandbox:

• No network access by default
• Filesystem isolated to sandbox temp directory
• 6 approved interpreters: python, node, powershell, bash, cmd.exe, dotnet
• 256 MB memory cap via OS-level enforcement
• Violation tracking — all violations logged to audit trail

Platform-Specific Enforcement

Platform	Mechanism
Linux	seccomp-bpf syscall whitelist (blocks socket, fork, mount, ptrace, keyctl)
Windows	Job Object memory limits + process isolation

Path Validation

All file paths validated before execution (cross-platform):

Check	Rejects
Empty path	""
Relative path	"documents/file.nda"
Path traversal	"../../etc/passwd"
Must be absolute	"./relative/file"

NDA Document Security

• Ed25519: Sign with compile_signed(), verify with verify_signature()
• Merkle tree: SHA-256 root of all triples, verified on parse
• Status: VERIFIED / UNSIGNED / FAILED (reported by read_nda)

Testing

284 tests verify security layers:

• 15 adversarial integration tests (path traversal, network blocking, tamper detection)
• 17 property-based fuzz tests (3,400+ random cases)
• Parser bounds checking, sandbox capabilities, signature verification

See also: Built-in-Tools, NDA-Format, Troubleshooting