diff --git a/.github/workflows/_release-rust.yml b/.github/workflows/_release-rust.yml
index 0211677..a549d5b 100644
--- a/.github/workflows/_release-rust.yml
+++ b/.github/workflows/_release-rust.yml
@@ -67,6 +67,31 @@ on:
         required: false
         type: string
         default: ""
+      # --- Code signing (opt-in; default off → no change for existing callers) ---
+      enable_signing:
+        description: "Enable OS code signing of built binaries"
+        required: false
+        type: boolean
+        default: false
+      notarize_macos:
+        description: "Submit macOS binaries for Apple notarization"
+        required: false
+        type: boolean
+        default: true
+      # NOTE: the CODESIGN_*/PGP_SIGN_* config values are declared under `secrets:`
+      # below (not here). Callers in public repos store them as secrets, and the
+      # `secrets` context cannot be referenced from a reusable-workflow `with:` —
+      # so they must be passed through the `secrets:` block.
+      jsign_sha256:
+        description: "Pinned sha256 of the jsign jar"
+        required: false
+        type: string
+        default: ""
+      rcodesign_sha256:
+        description: "Pinned sha256 of the rcodesign tarball"
+        required: false
+        type: string
+        default: ""
     secrets:
       app_id:
         description: "GitHub App ID"
@@ -74,9 +99,50 @@ on:
       app_pem:
         description: "GitHub App PEM"
         required: false
+      # Code-signing secrets. NOTE: no Apple secrets — macOS creds live in GCP
+      # Secret Manager (fetched via the CODESIGN_* identity).
+      pgp_cert_base64:
+        description: "Base64 OpenPGP public cert (Linux)"
+        required: false
+      pgp_signer_token:
+        description: "Token (GitHub App or PAT) with read on private kunobi-ninja/kunobi-pgp-kms"
+        required: false
+      windows_cert_chain:
+        description: "PKCS7 EV certificate chain (Windows Authenticode)"
+        required: false
+      # CODESIGN_*/PGP_SIGN_* config — passed as secrets (callers in public repos
+      # keep these out of Variables; secrets can't ride in a reusable-workflow `with:`).
+      codesign_wif_provider:
+        description: "WIF provider for code signing (Windows Authenticode + Apple Secret Manager)"
+        required: false
+      codesign_gcp_project:
+        description: "GCP project for code signing + Apple Secret Manager"
+        required: false
+      codesign_service_account:
+        description: "Service account to impersonate; empty = direct WIF"
+        required: false
+      codesign_kms_keyring:
+        description: "Authenticode KMS keyring"
+        required: false
+      codesign_kms_key_alias:
+        description: "Authenticode KMS key alias"
+        required: false
+      pgp_sign_wif_provider:
+        description: "WIF provider for OpenPGP KMS (Linux)"
+        required: false
+      pgp_sign_gcp_project_id:
+        description: "GCP project for OpenPGP KMS"
+        required: false
+      pgp_sign_service_account:
+        description: "Service account for OpenPGP KMS"
+        required: false
+      pgp_sign_kms_key_version:
+        description: "OpenPGP KMS key version path"
+        required: false
 
 permissions:
   contents: write
+  id-token: write
 
 jobs:
   # --- Job 1: Compute build matrix from target list ---
@@ -316,6 +382,56 @@ jobs:
             strip "$BIN"
           fi
 
+      # --- Code signing: all platforms sign the BINARY before packaging.
+      #     macOS/Windows embed the signature in the binary; Linux produces a
+      #     detached .asc that gets bundled into the archive next to the binary. ---
+      - name: Sign macOS binary
+        if: inputs.enable_signing && contains(matrix.target, 'apple-darwin')
+        uses: zondax/actions/sign-macos-binary@v1
+        with:
+          binary-path: target/${{ matrix.target }}/release/${{ inputs.binary_name }}
+          workload-identity-provider: ${{ secrets.codesign_wif_provider }}
+          gcp-project: ${{ secrets.codesign_gcp_project }}
+          service-account: ${{ secrets.codesign_service_account }}
+          notarize: ${{ inputs.notarize_macos }}
+          rcodesign-sha256: ${{ inputs.rcodesign_sha256 }}
+
+      - name: Authenticate with GCP (Authenticode)
+        id: auth-codesign
+        if: inputs.enable_signing && contains(matrix.target, 'windows')
+        uses: zondax/actions/gcp-wif-auth@v1
+        with:
+          workload_identity_provider: ${{ secrets.codesign_wif_provider }}
+          project_id: ${{ secrets.codesign_gcp_project }}
+          service_account: ${{ secrets.codesign_service_account }}
+          token_format: access_token
+          create_credentials_file: 'false'
+          setup_gcloud: 'false'
+          verify_authentication: 'false'
+
+      - name: Sign Windows binary
+        if: inputs.enable_signing && contains(matrix.target, 'windows')
+        uses: zondax/actions/sign-windows-binary@v1
+        with:
+          binary-path: target/${{ matrix.target }}/release/${{ inputs.binary_name }}.exe
+          gcp-access-token: ${{ steps.auth-codesign.outputs.access_token }}
+          kms-keyring: ${{ secrets.codesign_kms_keyring }}
+          kms-key-alias: ${{ secrets.codesign_kms_key_alias }}
+          cert-chain: ${{ secrets.windows_cert_chain }}
+          jsign-sha256: ${{ inputs.jsign_sha256 }}
+
+      - name: Sign Linux binary
+        if: inputs.enable_signing && contains(matrix.target, 'linux')
+        uses: zondax/actions/sign-linux-binary@v1
+        with:
+          target-path: target/${{ matrix.target }}/release/${{ inputs.binary_name }}
+          workload-identity-provider: ${{ secrets.pgp_sign_wif_provider }}
+          gcp-project-id: ${{ secrets.pgp_sign_gcp_project_id }}
+          service-account: ${{ secrets.pgp_sign_service_account }}
+          signer-token: ${{ secrets.pgp_signer_token }}
+          kms-key: ${{ secrets.pgp_sign_kms_key_version }}
+          cert-base64: ${{ secrets.pgp_cert_base64 }}
+
       - name: Package
         env:
           TARGET: ${{ matrix.target }}
@@ -335,9 +451,31 @@ jobs:
               (cd "target/$TARGET/release" && zip "$OLDPWD/$ARCHIVE" "${BINARY_NAME}${BINARY_EXT}")
             fi
           else
-            tar czf "$ARCHIVE" -C "target/$TARGET/release" "${BINARY_NAME}${BINARY_EXT}"
+            # Bundle the detached .asc (Linux binary signing) into the tarball
+            # next to the binary, so the signature travels with what it signs.
+            ASC="${BINARY_NAME}${BINARY_EXT}.asc"
+            if [ -f "target/$TARGET/release/$ASC" ]; then
+              tar czf "$ARCHIVE" -C "target/$TARGET/release" "${BINARY_NAME}${BINARY_EXT}" "$ASC"
+            else
+              tar czf "$ARCHIVE" -C "target/$TARGET/release" "${BINARY_NAME}${BINARY_EXT}"
+            fi
           fi
 
+      # Linux ALSO signs the packaged archive (detached .asc, top-level release
+      # asset) — in addition to the binary's .asc bundled inside it. Two PGP sigs:
+      # one over the ELF (inside the tarball), one over the .tar.gz (download).
+      - name: Sign Linux archive
+        if: inputs.enable_signing && contains(matrix.target, 'linux')
+        uses: zondax/actions/sign-linux-binary@v1
+        with:
+          target-path: ${{ inputs.binary_name }}-${{ matrix.target }}.${{ matrix.archive_ext }}
+          workload-identity-provider: ${{ secrets.pgp_sign_wif_provider }}
+          gcp-project-id: ${{ secrets.pgp_sign_gcp_project_id }}
+          service-account: ${{ secrets.pgp_sign_service_account }}
+          signer-token: ${{ secrets.pgp_signer_token }}
+          kms-key: ${{ secrets.pgp_sign_kms_key_version }}
+          cert-base64: ${{ secrets.pgp_cert_base64 }}
+
       - name: Checksum
         env:
           TARGET: ${{ matrix.target }}
@@ -364,6 +502,7 @@ jobs:
           path: |
             ${{ inputs.binary_name }}-${{ matrix.target }}.${{ matrix.archive_ext }}
             ${{ inputs.binary_name }}-${{ matrix.target }}.${{ matrix.archive_ext }}.sha256
+            ${{ inputs.binary_name }}-${{ matrix.target }}.${{ matrix.archive_ext }}.asc
 
   # --- Job 3: Create/upload GitHub Release ---
   release: