feat(cloud-agents): add thin nacl SecretBox wrapper for agent settings AWS creds + secrets

litellm/proxy/agent_settings_endpoints/encryption.py

@@ -0,0 +1,44 @@
+"""
+Thin encryption wrapper for the Cloud Agents settings endpoints.
+
+We do NOT roll a new KMS path here — we reuse the existing virtual-key
+nacl/SecretBox helpers (`encrypt_value_helper` / `decrypt_value_helper`) so
+operators only need to manage one `LITELLM_SALT_KEY`. The wrapper exists only
+to give the agent endpoints a single import surface and to centralize the
+"None passes through" semantics so callers don't sprinkle `if value is None`
+guards everywhere.
+
+Used for:
+* AWS BYOC creds on `LiteLLM_AgentVMConfig` (access key, secret key, role ARN)
+* Per-team secret values on `LiteLLM_AgentSecret`
+"""
+
+from typing import Optional
+
+from litellm.proxy.common_utils.encrypt_decrypt_utils import (
+    decrypt_value_helper,
+    encrypt_value_helper,
+)
+
+
+def encrypt_optional(value: Optional[str]) -> Optional[str]:
+    """Encrypt a value, passing None through.
+
+    Returns base64(urlsafe)-encoded ciphertext, or None if the input was None
+    or empty. Empty strings are normalized to None so `aws_role_arn=""` from
+    the wire round-trips cleanly to NULL in the DB.
+    """
+    if value is None or value == "":
+        return None
+    return encrypt_value_helper(value)
+
+
+def decrypt_optional(value: Optional[str], *, key: str) -> Optional[str]:
+    """Decrypt a previously-encrypted value, passing None through.
+
+    `key` is a debug-label only (used by the underlying helper to surface
+    which field failed to decrypt) — it is NOT a signing key.
+    """
+    if value is None or value == "":
+        return None
+    return decrypt_value_helper(value=value, key=key)