diff --git a/pkg/lvs/package.json b/pkg/lvs/package.json
index b30fd8c7..682537f8 100644
--- a/pkg/lvs/package.json
+++ b/pkg/lvs/package.json
@@ -28,6 +28,7 @@
   "dependencies": {
     "@ndn/packet": "workspace:*",
     "@ndn/tlv": "workspace:^",
+    "@ndn/trust-schema": "workspace:^",
     "@ndn/util": "workspace:*",
     "tslib": "^2.8.0"
   }
diff --git a/pkg/lvs/src/mod.ts b/pkg/lvs/src/mod.ts
index 88a39133..1cd29cfe 100644
--- a/pkg/lvs/src/mod.ts
+++ b/pkg/lvs/src/mod.ts
@@ -1 +1,2 @@
 export * as lvstlv from "./tlv";
+export * from "./translate";
diff --git a/pkg/lvs/src/translate.ts b/pkg/lvs/src/translate.ts
new file mode 100644
index 00000000..51dbaf0f
--- /dev/null
+++ b/pkg/lvs/src/translate.ts
@@ -0,0 +1,128 @@
+import { type Component, Name } from "@ndn/packet";
+import { pattern as P, TrustSchemaPolicy } from "@ndn/trust-schema";
+import { assert } from "@ndn/util";
+
+import { type ConsOption, type Constraint, type LvsModel, type Node, type PatternEdge, ValueEdge } from "./tlv";
+
+export function toPolicy(model: LvsModel): TrustSchemaPolicy {
+  return new Translator(model).translate();
+}
+
+class Translator {
+  constructor(private readonly model: LvsModel) {}
+
+  private readonly policy = new TrustSchemaPolicy();
+  private readonly tagSymbols = new Map<number, string>();
+  private readonly wantedNodes = new Set<number>();
+  private lastAutoId = 0;
+
+  public translate(): TrustSchemaPolicy {
+    this.gatherTagSymbols();
+    this.gatherNodes();
+    this.processPatterns();
+    this.processRules();
+    return this.policy;
+  }
+
+  private gatherTagSymbols(): void {
+    this.tagSymbols.clear();
+    for (const { tag, identifier } of this.model.tagSymbols) {
+      this.tagSymbols.set(tag, identifier);
+    }
+  }
+
+  private nameTag(tag: number): string {
+    // TODO
+    const prefix = this.tagSymbols.get(tag) ?? `_TAG_${tag}`;
+    const suffix = tag > this.model.namedPatternCnt ? `_${++this.lastAutoId}` : "";
+    return `${prefix}${suffix}`;
+  }
+
+  private gatherNodes(): void {
+    this.wantedNodes.clear();
+    for (const node of this.model.nodes) {
+      if (node.ruleNames.length > 0 || node.signConstraints.length > 0) {
+        this.wantedNodes.add(node.id);
+      }
+      for (const sc of node.signConstraints) {
+        this.wantedNodes.add(sc);
+      }
+    }
+  }
+
+  private processPatterns(): void {
+    for (const id of this.wantedNodes) {
+      const node = this.model.nodes[id]!;
+      const pattern = this.trPattern(node).simplify();
+      for (const name of this.namePattern(node)) {
+        this.policy.addPattern(name, pattern);
+      }
+    }
+  }
+
+  private namePattern(node: Node): string[] {
+    if (node.ruleNames.length === 0) {
+      return [`_NODE_${node.id}`];
+    }
+    return node.ruleNames;
+  }
+
+  private trPattern(node: Node): P.Pattern {
+    const parts: P.Pattern[] = [];
+    while (node.parent !== undefined) {
+      const parent = this.model.nodes[node.parent]!;
+      const edge = parent.findEdgeTo(node.id)!;
+      parts.unshift(this.trEdge(edge));
+      node = parent;
+    }
+    return new P.ConcatPattern(parts);
+  }
+
+  private trEdge(edge: ValueEdge | PatternEdge): P.Pattern {
+    if (edge instanceof ValueEdge) {
+      return this.trValue(edge.value);
+    }
+
+    // TODO
+    assert(edge.constraints.length <= 1, "PatternEdge with multiple Constraints is unimplemented");
+    const inner = edge.constraints[0] && this.trConstraint(edge.constraints[0]);
+    return new P.VariablePattern(this.nameTag(edge.tag), { inner });
+  }
+
+  private trConstraint(cons: Constraint): P.Pattern {
+    return new P.AlternatePattern(
+      Array.from(cons.options, (co) => this.trConsOption(co)),
+    );
+  }
+
+  private trConsOption(co: ConsOption): P.Pattern {
+    if (co.value) {
+      return this.trValue(co.value);
+    }
+    if (co.tag) {
+      return new P.VariablePattern(this.nameTag(co.tag));
+    }
+    assert(co.call);
+    // TODO
+    assert(false, "UserFnCall is unimplemented");
+  }
+
+  private trValue(value: Component): P.Pattern {
+    return new P.ConstPattern(new Name([value]));
+  }
+
+  private processRules(): void {
+    for (const node of this.model.nodes) {
+      const packetIds = this.namePattern(node);
+      for (const sc of node.signConstraints) {
+        const signerIds = this.namePattern(this.model.nodes[sc]!);
+
+        for (const packetId of packetIds) {
+          for (const signerId of signerIds) {
+            this.policy.addRule(packetId, signerId);
+          }
+        }
+      }
+    }
+  }
+}
diff --git a/pkg/lvs/test-fixture/lvstlv.ts b/pkg/lvs/test-fixture/lvstlv.ts
index 29970e6e..6a123c4e 100644
--- a/pkg/lvs/test-fixture/lvstlv.ts
+++ b/pkg/lvs/test-fixture/lvstlv.ts
@@ -1,22 +1,22 @@
-import fs from "node:fs/promises";
+import fs from "node:fs";
 import path from "node:path";
 
 import { Decoder } from "@ndn/tlv";
 
 import { lvstlv } from "..";
 
-async function loadLVSTLV(filename: string): Promise<lvstlv.LvsModel> {
-  return Decoder.decode(
-    await fs.readFile(path.join(import.meta.dirname, filename)),
+function loadLVSTLV(filename: string): () => lvstlv.LvsModel {
+  return () => Decoder.decode(
+    fs.readFileSync(path.join(import.meta.dirname, filename)),
     lvstlv.LvsModel,
   );
 }
 
 /** python-ndn LVS model sample "quick example". */
-export const pyndn0 = await loadLVSTLV("pyndn0.tlv");
+export const pyndn0 = loadLVSTLV("pyndn0.tlv");
 
 /** python-ndn LVS model sample "signing key suggesting". */
-export const pyndn1 = await loadLVSTLV("pyndn1.tlv");
+export const pyndn1 = loadLVSTLV("pyndn1.tlv");
 
 /** python-ndn LVS model sample "compiler and checker demonstration". */
-export const pyndn2 = await loadLVSTLV("pyndn2.tlv");
+export const pyndn2 = loadLVSTLV("pyndn2.tlv");
diff --git a/pkg/lvs/tests/lvstlv.t.ts b/pkg/lvs/tests/lvstlv.t.ts
deleted file mode 100644
index 37a17f15..00000000
--- a/pkg/lvs/tests/lvstlv.t.ts
+++ /dev/null
@@ -1,17 +0,0 @@
-import { console } from "@ndn/util";
-import { expect, test } from "vitest";
-
-import { pyndn0, pyndn1, pyndn2 } from "../test-fixture/lvstlv";
-
-test("pyndn0", () => {
-  console.log(pyndn0.toString());
-});
-
-test("pyndn1", () => {
-  console.log(pyndn1.toString());
-  expect(pyndn1.nodes).toHaveLength(26);
-});
-
-test("pyndn2", () => {
-  console.log(pyndn2.toString());
-});
diff --git a/pkg/lvs/tests/pyndn.t.ts b/pkg/lvs/tests/pyndn.t.ts
new file mode 100644
index 00000000..b8ad89ae
--- /dev/null
+++ b/pkg/lvs/tests/pyndn.t.ts
@@ -0,0 +1,39 @@
+import { Name } from "@ndn/packet";
+// import { printESM, versec } from "@ndn/trust-schema";
+import { console } from "@ndn/util";
+import { expect, test } from "vitest";
+
+import { toPolicy } from "..";
+import { pyndn0, pyndn1, pyndn2 } from "../test-fixture/lvstlv";
+
+test("pyndn0", () => {
+  const model = pyndn0();
+  // console.log(model.toString());
+
+  const policy = toPolicy(model);
+  // console.log(printESM(policy));
+  // console.log(versec.print(policy));
+  expect(policy.canSign(
+    new Name("/a/blog/article/math/2022/03"),
+    new Name("/a/blog/author/xinyu/KEY/1/admin/1"),
+  )).toBeTruthy();
+  expect(policy.canSign(
+    new Name("/a/blog/author/xinyu/KEY/1/admin/1"),
+    new Name("/a/blog/admin/admin/KEY/1/root/1"),
+  )).toBeTruthy();
+  expect(policy.canSign(
+    new Name("/a/blog/author/xinyu/KEY/1/admin/1"),
+    new Name("/a/blog/KEY/1/self/1"),
+  )).toBeFalsy();
+});
+
+test("pyndn1", () => {
+  const model = pyndn1();
+  console.log(model.toString());
+  expect(model.nodes).toHaveLength(26);
+});
+
+test("pyndn2", () => {
+  const model = pyndn2();
+  console.log(model.toString());
+});
diff --git a/pkg/tlv/src/impl-field.ts b/pkg/tlv/src/impl-field.ts
index bf23f4a1..162bf5e9 100644
--- a/pkg/tlv/src/impl-field.ts
+++ b/pkg/tlv/src/impl-field.ts
@@ -10,23 +10,14 @@ export interface Field<T> extends Required<EvDecoder.RuleOptions> {
   asString: (v: T) => Iterable<string>;
 }
 
-interface Options extends EvDecoder.RuleOptions {
-  required?: boolean;
-  repeat?: boolean;
-}
-
 export function makeField<T>(
     tt: number,
     key: string,
     type: StructFieldType<T>,
-    opts: Options,
+    opts: EvDecoder.RuleOptions,
     evd: EvDecoder<any>,
 ): Field<T[]> | Field<T | undefined> {
-  const fo = { ...opts, ...(evd ? evd.applyDefaultsToRuleOptions(opts) : {
-    order: tt,
-    required: false,
-    repeat: false,
-  }) };
+  const fo = evd.applyDefaultsToRuleOptions(opts);
   evd.add(
     tt,
     fo.repeat ?
diff --git a/pkg/trust-schema/src/schema/pattern.ts b/pkg/trust-schema/src/schema/pattern.ts
index 997beb3e..f9d01bea 100644
--- a/pkg/trust-schema/src/schema/pattern.ts
+++ b/pkg/trust-schema/src/schema/pattern.ts
@@ -209,6 +209,17 @@ export class VariablePattern extends Pattern {
   public readonly inner?: Pattern;
   public readonly filter?: VariablePattern.Filter;
 
+  public override simplify(): Pattern {
+    const inner = this.inner?.simplify();
+    if (inner === this.inner) {
+      return this;
+    }
+    return new VariablePattern(this.id, {
+      ...this,
+      inner,
+    });
+  }
+
   private *innerMatch(value: Name, input?: Map<string, Name>): Iterable<Vars> {
     if (!this.inner) {
       yield new Map<string, Name>();