diff --git a/.clusterfuzzlite/Dockerfile b/.clusterfuzzlite/Dockerfile
new file mode 100644
index 000000000..0a89c8dc8
--- /dev/null
+++ b/.clusterfuzzlite/Dockerfile
@@ -0,0 +1,9 @@
+FROM gcr.io/oss-fuzz-base/base-builder-python
+
+RUN apt-get update && apt-get install -y --no-install-recommends \
+    protobuf-compiler \
+    && rm -rf /var/lib/apt/lists/*
+
+COPY . $SRC/hiero-sdk-python
+WORKDIR $SRC/hiero-sdk-python
+COPY .clusterfuzzlite/build.sh $SRC/
diff --git a/.clusterfuzzlite/build.sh b/.clusterfuzzlite/build.sh
new file mode 100644
index 000000000..406ccb8e9
--- /dev/null
+++ b/.clusterfuzzlite/build.sh
@@ -0,0 +1,32 @@
+#!/bin/bash -eu
+
+pip3 install grpcio-tools
+
+python3 generate_proto.py
+
+pip3 install .
+
+pip3 install atheris pyinstaller
+
+find "$SRC/hiero-sdk-python/.clusterfuzzlite" -name '*_fuzzer.py' -print0 | while IFS= read -r -d '' fuzzer; do
+  fuzzer_basename=$(basename -s .py "$fuzzer")
+  fuzzer_package="${fuzzer_basename}.pkg"
+
+  # Bundle the fuzzer and all its dependencies into a single portable package.
+  pyinstaller --distpath "$OUT" --onefile --name "$fuzzer_package" "$fuzzer"
+
+  # Write a thin shell wrapper that ClusterFuzzLite uses to invoke the fuzzer.
+  # The wrapper preloads the sanitizer library and sets ASAN_OPTIONS.
+  # LD_PRELOAD is required here because the SDK uses C extensions (grpcio,
+  # cryptography, protobuf) that must be covered by the sanitizer.
+  cat > "$OUT/$fuzzer_basename" << EOF
+#!/bin/sh
+# LLVMFuzzerTestOneInput for fuzzer detection.
+this_dir=\$(dirname "\$0")
+LD_PRELOAD=\$this_dir/sanitizer_with_fuzzer.so \\
+PYCRYPTODOME_DISABLE_DEEPBIND=1 \\
+ASAN_OPTIONS=\$ASAN_OPTIONS:symbolize=1:external_symbolizer_path=\$this_dir/llvm-symbolizer:detect_leaks=0 \\
+  "\$this_dir/$fuzzer_package" "\$@"
+EOF
+  chmod +x "$OUT/$fuzzer_basename"
+done
diff --git a/.clusterfuzzlite/contract_params_fuzzer.py b/.clusterfuzzlite/contract_params_fuzzer.py
new file mode 100644
index 000000000..f859ed95e
--- /dev/null
+++ b/.clusterfuzzlite/contract_params_fuzzer.py
@@ -0,0 +1,55 @@
+"""Atheris fuzz target: ContractFunctionParameters ABI encoding."""
+
+from __future__ import annotations
+
+import sys
+
+import atheris
+
+
+with atheris.instrument_imports():
+    from eth_abi.exceptions import EncodingTypeError, ValueOutOfBounds
+
+    from hiero_sdk_python import ContractFunctionParameters
+
+
+def TestOneInput(data: bytes) -> None:
+    """Feed arbitrary bytes into ContractFunctionParameters encoding paths."""
+    fdp = atheris.FuzzedDataProvider(data)
+    choice = fdp.ConsumeIntInRange(0, 9)
+    params = ContractFunctionParameters()
+    if choice == 0:
+        params.add_bool(fdp.ConsumeBool())
+    elif choice == 1:
+        # add_address expects a 20-byte hex string or bytes
+        params.add_address(fdp.ConsumeBytes(20).hex())
+    elif choice == 2:
+        params.add_string(fdp.ConsumeUnicodeNoSurrogates(256))
+    elif choice == 3:
+        params.add_bytes(fdp.ConsumeBytes(256))
+    elif choice == 4:
+        params.add_bytes32(fdp.ConsumeBytes(32))
+    elif choice == 5:
+        count = fdp.ConsumeIntInRange(0, 8)
+        params.add_bool_array([fdp.ConsumeBool() for _ in range(count)])
+    elif choice == 6:
+        count = fdp.ConsumeIntInRange(0, 8)
+        params.add_string_array([fdp.ConsumeUnicodeNoSurrogates(64) for _ in range(count)])
+    elif choice == 7:
+        count = fdp.ConsumeIntInRange(0, 8)
+        params.add_bytes_array([fdp.ConsumeBytes(32) for _ in range(count)])
+    elif choice == 8:
+        count = fdp.ConsumeIntInRange(0, 8)
+        params.add_address_array([fdp.ConsumeBytes(20).hex() for _ in range(count)])
+    else:
+        count = fdp.ConsumeIntInRange(0, 8)
+        params.add_bytes32_array([fdp.ConsumeBytes(32) for _ in range(count)])
+    try:
+        params.to_bytes()
+    except (TypeError, ValueError, EncodingTypeError, ValueOutOfBounds):
+        # Malformed fuzz input can trigger expected validation/ABI encoding failures.
+        pass
+
+
+atheris.Setup(sys.argv, TestOneInput)
+atheris.Fuzz()
diff --git a/.clusterfuzzlite/entity_id_fuzzer.py b/.clusterfuzzlite/entity_id_fuzzer.py
new file mode 100644
index 000000000..fdbbc509f
--- /dev/null
+++ b/.clusterfuzzlite/entity_id_fuzzer.py
@@ -0,0 +1,34 @@
+"""Atheris fuzz target: entity ID string parsing."""
+
+from __future__ import annotations
+
+import sys
+
+import atheris
+
+
+with atheris.instrument_imports():
+    from hiero_sdk_python import AccountId, ContractId, FileId, TokenId, TopicId
+
+_CLASSES = (AccountId, TokenId, ContractId, FileId, TopicId)
+
+
+def _try_parse_entity_id(entity_id_class, text: str) -> None:
+    try:
+        entity_id_class.from_string(text)
+    except (TypeError, ValueError, IndexError, OverflowError):
+        # Expected errors from malformed string input (parsing, indexing, conversions)
+        pass
+
+
+def TestOneInput(data: bytes) -> None:
+    """Feed arbitrary strings into entity ID parsers."""
+    fdp = atheris.FuzzedDataProvider(data)
+    text = fdp.ConsumeUnicodeNoSurrogates(256)
+
+    for cls in _CLASSES:
+        _try_parse_entity_id(cls, text)
+
+
+atheris.Setup(sys.argv, TestOneInput)
+atheris.Fuzz()
diff --git a/.clusterfuzzlite/keys_fuzzer.py b/.clusterfuzzlite/keys_fuzzer.py
new file mode 100644
index 000000000..c60540bd0
--- /dev/null
+++ b/.clusterfuzzlite/keys_fuzzer.py
@@ -0,0 +1,45 @@
+"""Atheris fuzz target: PrivateKey and PublicKey parsing."""
+
+from __future__ import annotations
+
+import sys
+import warnings
+
+import atheris
+
+
+with atheris.instrument_imports():
+    from hiero_sdk_python import PrivateKey, PublicKey
+
+
+def _quiet(fn, *args):
+    """Call *fn* with *args*, suppressing UserWarning."""
+    with warnings.catch_warnings():
+        warnings.simplefilter("ignore", UserWarning)
+        return fn(*args)
+
+
+def TestOneInput(data: bytes) -> None:
+    """Feed arbitrary bytes/strings into key parsers."""
+    fdp = atheris.FuzzedDataProvider(data)
+    choice = fdp.ConsumeIntInRange(0, 3)
+
+    try:
+        if choice == 0:
+            text = fdp.ConsumeUnicodeNoSurrogates(256)
+            _quiet(PrivateKey.from_string, text)
+        elif choice == 1:
+            raw = fdp.ConsumeBytes(128)
+            _quiet(PrivateKey.from_bytes, raw)
+        elif choice == 2:
+            text = fdp.ConsumeUnicodeNoSurrogates(256)
+            _quiet(PublicKey.from_string, text)
+        else:
+            raw = fdp.ConsumeBytes(128)
+            _quiet(PublicKey.from_bytes, raw)
+    except ValueError:
+        pass
+
+
+atheris.Setup(sys.argv, TestOneInput)
+atheris.Fuzz()
diff --git a/.clusterfuzzlite/project.yaml b/.clusterfuzzlite/project.yaml
new file mode 100644
index 000000000..d1ad0ae50
--- /dev/null
+++ b/.clusterfuzzlite/project.yaml
@@ -0,0 +1 @@
+language: python
diff --git a/.clusterfuzzlite/transaction_from_bytes_fuzzer.py b/.clusterfuzzlite/transaction_from_bytes_fuzzer.py
new file mode 100644
index 000000000..c86bec7ba
--- /dev/null
+++ b/.clusterfuzzlite/transaction_from_bytes_fuzzer.py
@@ -0,0 +1,27 @@
+"""Atheris fuzz target: Transaction.from_bytes deserialization."""
+
+from __future__ import annotations
+
+import sys
+
+import atheris
+
+
+with atheris.instrument_imports():
+    from hiero_sdk_python import Transaction
+
+
+def TestOneInput(data: bytes) -> None:
+    """Feed arbitrary bytes into Transaction.from_bytes and re-serialise."""
+    try:
+        tx = Transaction.from_bytes(data)
+        tx.to_bytes()
+    except Exception:
+        # Protobuf deserialization and transaction parsing can raise many
+        # exception types (DecodeError, ValueError, TypeError, KeyError, etc.);
+        # only unhandled exceptions that escape are reported as fuzzer crashes.
+        pass
+
+
+atheris.Setup(sys.argv, TestOneInput)
+atheris.Fuzz()
diff --git a/.codacy.yml b/.codacy.yml
index d83fecdd1..d54a0239e 100644
--- a/.codacy.yml
+++ b/.codacy.yml
@@ -1,6 +1,7 @@
 ---
 exclude_paths:
   - "tck/**"
+  - ".clusterfuzzlite/**"
 
 engines:
   bandit:
diff --git a/.github/workflows/clusterfuzzlite.yml b/.github/workflows/clusterfuzzlite.yml
new file mode 100644
index 000000000..56390b9e0
--- /dev/null
+++ b/.github/workflows/clusterfuzzlite.yml
@@ -0,0 +1,76 @@
+name: ClusterFuzzLite
+
+on:
+  pull_request:
+  push:
+    branches:
+      - main
+
+permissions: read-all
+
+jobs:
+  # ── PR fuzzing ────────────────────────────────────────────────────────────
+  # Runs on every pull request and reports any new crashes found in the
+  # changed code paths (code-change mode).
+  PR:
+    if: github.event_name == 'pull_request'
+    runs-on: hl-sdk-py-lin-md
+    concurrency:
+      group: ${{ github.workflow }}-pr-${{ matrix.sanitizer }}-${{ github.ref }}
+      cancel-in-progress: true
+    strategy:
+      fail-fast: false
+      matrix:
+        sanitizer:
+          - address
+    steps:
+      - name: Harden the runner (Audit all outbound calls)
+        uses: step-security/harden-runner@6c3c2f2c1c457b00c10c4848d6f5491db3b629df # v2.18.0
+        with:
+          egress-policy: audit
+
+      - name: Build Fuzzers (${{ matrix.sanitizer }})
+        id: build
+        uses: google/clusterfuzzlite/actions/build_fuzzers@884713a6c30a92e5e8544c39945cd7cb630abcd1 # v1
+        with:
+          language: python
+          github-token: ${{ secrets.GITHUB_TOKEN }}
+          sanitizer: ${{ matrix.sanitizer }}
+
+      - name: Run Fuzzers (${{ matrix.sanitizer }})
+        id: run
+        uses: google/clusterfuzzlite/actions/run_fuzzers@884713a6c30a92e5e8544c39945cd7cb630abcd1 # v1
+        with:
+          github-token: ${{ secrets.GITHUB_TOKEN }}
+          fuzz-seconds: 600
+          mode: code-change
+          sanitizer: ${{ matrix.sanitizer }}
+          output-sarif: true
+
+  # ── Continuous builds ─────────────────────────────────────────────────────
+  # Uploads a fresh fuzzer build artifact on every push to main so that PR
+  # fuzzing can determine whether a crash was newly introduced.
+  Build:
+    if: github.event_name == 'push'
+    runs-on: hl-sdk-py-lin-md
+    concurrency:
+      group: ${{ github.workflow }}-build-${{ matrix.sanitizer }}-${{ github.ref }}
+      cancel-in-progress: true
+    strategy:
+      fail-fast: false
+      matrix:
+        sanitizer:
+          - address
+    steps:
+      - name: Harden the runner (Audit all outbound calls)
+        uses: step-security/harden-runner@6c3c2f2c1c457b00c10c4848d6f5491db3b629df # v2.18.0
+        with:
+          egress-policy: audit
+
+      - name: Build Fuzzers (${{ matrix.sanitizer }})
+        id: build
+        uses: google/clusterfuzzlite/actions/build_fuzzers@884713a6c30a92e5e8544c39945cd7cb630abcd1 # v1
+        with:
+          language: python
+          sanitizer: ${{ matrix.sanitizer }}
+          upload-build: true
diff --git a/src/hiero_sdk_python/__init__.py b/src/hiero_sdk_python/__init__.py
index 329f6f0a4..b890f3330 100644
--- a/src/hiero_sdk_python/__init__.py
+++ b/src/hiero_sdk_python/__init__.py
@@ -31,6 +31,7 @@
 from .contract.contract_execute_transaction import ContractExecuteTransaction
 from .contract.contract_function_parameters import ContractFunctionParameters
 from .contract.contract_function_result import ContractFunctionResult
+from .contract.contract_id import ContractId
 from .contract.contract_info import ContractInfo
 from .contract.contract_info_query import ContractInfoQuery
 from .contract.contract_update_transaction import ContractUpdateTransaction
@@ -52,6 +53,7 @@
 from .file.file_contents_query import FileContentsQuery
 from .file.file_create_transaction import FileCreateTransaction
 from .file.file_delete_transaction import FileDeleteTransaction
+from .file.file_id import FileId
 from .file.file_info import FileInfo
 from .file.file_info_query import FileInfoQuery
 from .file.file_update_transaction import FileUpdateTransaction
@@ -249,6 +251,7 @@
     # File
     "FileCreateTransaction",
     "FileAppendTransaction",
+    "FileId",
     "FileInfoQuery",
     "FileInfo",
     "FileContentsQuery",
@@ -257,6 +260,7 @@
     # Contract
     "ContractCreateTransaction",
     "ContractCallQuery",
+    "ContractId",
     "ContractInfoQuery",
     "ContractBytecodeQuery",
     "ContractExecuteTransaction",