diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
new file mode 100644
index 0000000..41546ee
--- /dev/null
+++ b/.github/workflows/ci.yml
@@ -0,0 +1,34 @@
+name: Python CI
+
+on:
+  push:
+    branches: [ "main" ]
+  pull_request:
+    branches: [ "main" ]
+
+jobs:
+  build:
+
+    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        python-version: ["3.8", "3.9", "3.10", "3.11", "3.12"]
+
+    steps:
+    - uses: actions/checkout@v4
+    - name: Set up Python ${{ matrix.python-version }}
+      uses: actions/setup-python@v5
+      with:
+        python-version: ${{ matrix.python-version }}
+    - name: Install dependencies
+      run: |
+        python -m pip install --upgrade pip
+        pip install poetry
+        poetry install
+    - name: Test with unittest
+      run: |
+        poetry run coverage run -m unittest discover tests
+    - name: Upload coverage reports to Codecov
+      uses: codecov/codecov-action@v5
+      with:
+        token: ${{ secrets.CODECOV_TOKEN }}
diff --git a/.github/workflows/python-ci.yml b/.github/workflows/python-ci.yml
deleted file mode 100644
index f7fb08b..0000000
--- a/.github/workflows/python-ci.yml
+++ /dev/null
@@ -1,42 +0,0 @@
-name: Python CI
-
-on:
-  push:
-    branches: [ main ]
-  pull_request:
-    branches: [ main ]
-
-jobs:
-  test:
-    runs-on: ubuntu-latest
-    strategy:
-      matrix:
-        python-version: ['3.9', '3.10', '3.11']
-
-    steps:
-    - uses: actions/checkout@v4
-    
-    - name: Set up Python ${{ matrix.python-version }}
-      uses: actions/setup-python@v5
-      with:
-        python-version: ${{ matrix.python-version }}
-    
-    - name: Install dependencies
-      run: |
-        python -m pip install --upgrade pip
-        pip install pytest pytest-cov
-        if [ -f requirements.txt ]; then pip install -r requirements.txt; fi
-    
-    - name: Run unit tests
-      run: |
-        pytest tests/unittests/ -v --cov=passifypdf --cov-report=xml --cov-report=term
-    
-    - name: Run integration tests
-      run: |
-        pytest tests/integrationtests/ -v
-    
-    - name: Upload coverage to Codecov
-      uses: codecov/codecov-action@v4
-      with:
-        file: ./coverage.xml
-        fail_ci_if_error: false
diff --git a/README.md b/README.md
index 5ceaa39..1c96951 100644
--- a/README.md
+++ b/README.md
@@ -8,47 +8,40 @@ Same as encrypt or lock your PDF via a password.
 # How to use ?
 
 ## Clone
-```
-git clone git@github.com:SUPAIDEAS/passifypdf.git
-```
-or 
-```
+```bash
 git clone https://github.com/SUPAIDEAS/passifypdf.git
 ```
 
-## Pull Dependencies (install before usage)
+## Install Dependencies
+Uses [Poetry](https://python-poetry.org/) for dependency management.
 
-```
-pip install -r requirements.txt
+```bash
+cd passifypdf
+pip install poetry
+poetry install
 ```
 
 ## Usage
+Run the CLI tool using `poetry run`:
 
-Run the "main" from IDE or from CLI:
-
-```
-if __name__ == "__main__":
-    ...
+```bash
+poetry run passifypdf --help
 ```
 
-## Usage via CLI:
-
-```
-python encryptpdf.py
+Or activate the shell:
+```bash
+poetry shell
+passifypdf --help
 ```
 
-Sample Run:
-```
-change dir to "passifypdf/passifypdf", 
 
-Then run, 
-python encryptpdf.py
+Sample Run:
+```bash
+passifypdf -i input.pdf -o protected.pdf -p mySecretPassword
 
--------------------------Sample output----------------------
-$python encryptpdf.py
-Congratulations!
-PDF file encrypted successfully and saved as 'Sample_PDF_protected.pdf'
-$
+# -------------------------Sample output----------------------
+# Congratulations!
+# PDF file encrypted successfully and saved as 'protected.pdf'
 ```
 
 ## Known Issues
diff --git a/docs/CLI_OPTIONS.md b/docs/CLI_OPTIONS.md
new file mode 100644
index 0000000..6442abc
--- /dev/null
+++ b/docs/CLI_OPTIONS.md
@@ -0,0 +1,18 @@
+# CLI Options
+
+The `passifypdf` tool accepts the following command-line arguments:
+
+| Option | Long Option | Required | Description |
+| :--- | :--- | :--- | :--- |
+| `-i` | `--input` | Yes | Path to the input PDF file. |
+| `-o` | `--output` | Yes | Path to the output (encrypted) PDF file. |
+| `-p` | `--passwd` | Yes | Password to use for encryption. **Avoid passing sensitive passwords directly on the command line, as they may be exposed via process listings and shell history.** |
+| `-v` | `--version` | No | Show the program's version number and exit. |
+| `-h` | `--help` | No | Show the help message and exit. |
+
+## Example Usage
+
+```bash
+# Using the installed CLI command (after `poetry install`)
+passifypdf -i input.pdf -o protected.pdf -p mySecretPassword
+```
diff --git a/passifypdf/__init__.py b/passifypdf/__init__.py
index 79b42da..f7b86a0 100644
--- a/passifypdf/__init__.py
+++ b/passifypdf/__init__.py
@@ -1 +1 @@
-"""Unit test package for {{ cookiecutter.project_slug }}."""
+"""passifypdf - Protect PDF files with a password of your choice."""
diff --git a/passifypdf/cli.py b/passifypdf/cli.py
index 3f2daa1..7364188 100644
--- a/passifypdf/cli.py
+++ b/passifypdf/cli.py
@@ -1,10 +1,13 @@
 import argparse
 
 
-def get_arg_parser():
-    arg_parser = argparse.ArgumentParser(description=("Encrypt a PDF file with a password of your choice."), epilog=("For more information, visit: https://github.com/SUPAIDEAS/passifypdf"))
+def get_arg_parser() -> argparse.ArgumentParser:
+    arg_parser = argparse.ArgumentParser(
+        description="Encrypt a PDF file with a password of your choice.",
+        epilog="For more information, visit: https://github.com/SUPAIDEAS/passifypdf"
+    )
     arg_parser.add_argument("-v", "--version", action="version", version="%(prog)s 1.0")
-    arg_parser.add_argument("-i", "--input", required=True, help="path to the input pdf file")
-    arg_parser.add_argument("-o", "--output", required=True, help="path to the output encrypted pdf file")
-    arg_parser.add_argument("-p", "--passwd", required=True, type=str, help="password to encrypt the pdf file")
+    arg_parser.add_argument("-i", "--input", required=True, help="Path to the input PDF file to be encrypted")
+    arg_parser.add_argument("-o", "--output", required=True, help="Path where the encrypted PDF file will be saved")
+    arg_parser.add_argument("-p", "--passwd", required=True, type=str, help="Password to encrypt the PDF file with")
     return arg_parser
\ No newline at end of file
diff --git a/passifypdf/encryptpdf.py b/passifypdf/encryptpdf.py
index 077eebf..e326cab 100644
--- a/passifypdf/encryptpdf.py
+++ b/passifypdf/encryptpdf.py
@@ -1,33 +1,72 @@
-from cli import get_arg_parser
+"""Core PDF encryption module."""
+
+import sys
+from pathlib import Path
+from typing import Union
+
 from pypdf import PdfReader, PdfWriter
 
+from .cli import get_arg_parser
+
+
+def encrypt_pdf(input_pdf: Union[str, Path], output_pdf: Union[str, Path], password: str) -> None:
+    """
+    Encrypts a PDF file with a password.
 
-def encrypt_pdf(input_pdf, output_pdf, password):
-    reader = PdfReader(input_pdf)
-    writer = PdfWriter()
+    Args:
+        input_pdf (Union[str, Path]): Path to the input PDF file.
+        output_pdf (Union[str, Path]): Path to the output PDF file.
+        password (str): Password to encrypt the PDF with.
 
-    # Add all pages from the reader to the writer
-    for page_num in range(len(reader.pages)):
-        writer.add_page(reader.pages[page_num])
+    Raises:
+        FileNotFoundError: If the input PDF file does not exist.
+        IsADirectoryError: If the input path is a directory.
+        Exception: For other errors during processing.
+    """
+    input_path = Path(input_pdf)
+    if not input_path.exists():
+        raise FileNotFoundError(f"Input file '{input_pdf}' not found.")
 
-    # Encrypt with a password
-    writer.encrypt(password)
+    if not input_path.is_file():
+        raise IsADirectoryError(f"Input path '{input_pdf}' is not a file.")
 
-    # Write the encrypted PDF to a new PDF file passed as param
-    with open(output_pdf, "wb") as f:
-        writer.write(f)
+    try:
+        reader = PdfReader(input_path)
+        writer = PdfWriter()
 
+        # Add all pages from the reader to the writer
+        for page in reader.pages:
+            writer.add_page(page)
 
-def pipeline(any_thing):
-    return any_thing
+        # Encrypt with a password
+        writer.encrypt(password)
 
+        # Write the encrypted PDF to a new PDF file passed as param
+        with open(output_pdf, "wb") as f:
+            writer.write(f)
 
-def main():
+    except Exception as e:
+        raise Exception(f"Failed to encrypt PDF: {e}")
+
+
+def main() -> int:
+    """
+    Main function to run the CLI.
+
+    Returns:
+        int: Exit code (0 for success, 1 for failure).
+    """
     arg_parser = get_arg_parser()
     args = arg_parser.parse_args()
-    encrypt_pdf(args.input, args.output, args.passwd)
-    print(f"Congratulations!\nPDF file encrypted successfully and saved as '{args.output}'")
+
+    try:
+        encrypt_pdf(args.input, args.output, args.passwd)
+        print(f"Congratulations!\nPDF file encrypted successfully and saved as '{args.output}'")
+        return 0
+    except Exception as e:
+        print(f"Error: {e}", file=sys.stderr)
+        return 1
 
 
 if __name__ == "__main__":
-    main()
\ No newline at end of file
+    sys.exit(main())
\ No newline at end of file
diff --git a/poetry.lock b/poetry.lock
new file mode 100644
index 0000000..ce22814
--- /dev/null
+++ b/poetry.lock
@@ -0,0 +1,126 @@
+# This file is automatically @generated by Poetry 2.3.1 and should not be changed by hand.
+
+[[package]]
+name = "coverage"
+version = "7.6.1"
+description = "Code coverage measurement for Python"
+optional = false
+python-versions = ">=3.8"
+groups = ["dev"]
+files = [
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+    {file = "coverage-7.6.1.tar.gz", hash = "sha256:953510dfb7b12ab69d20135a0662397f077c59b1e6379a768e97c59d852ee51d"},
+]
+
+[package.extras]
+toml = ["tomli ; python_full_version <= \"3.11.0a6\""]
+
+[[package]]
+name = "pypdf"
+version = "4.3.1"
+description = "A pure-python PDF library capable of splitting, merging, cropping, and transforming PDF files"
+optional = false
+python-versions = ">=3.6"
+groups = ["main"]
+files = [
+    {file = "pypdf-4.3.1-py3-none-any.whl", hash = "sha256:64b31da97eda0771ef22edb1bfecd5deee4b72c3d1736b7df2689805076d6418"},
+    {file = "pypdf-4.3.1.tar.gz", hash = "sha256:b2f37fe9a3030aa97ca86067a56ba3f9d3565f9a791b305c7355d8392c30d91b"},
+]
+
+[package.dependencies]
+typing_extensions = {version = ">=4.0", markers = "python_version < \"3.11\""}
+
+[package.extras]
+crypto = ["PyCryptodome ; python_version == \"3.6\"", "cryptography ; python_version >= \"3.7\""]
+dev = ["black", "flit", "pip-tools", "pre-commit (<2.18.0)", "pytest-cov", "pytest-socket", "pytest-timeout", "pytest-xdist", "wheel"]
+docs = ["myst_parser", "sphinx", "sphinx_rtd_theme"]
+full = ["Pillow (>=8.0.0)", "PyCryptodome ; python_version == \"3.6\"", "cryptography ; python_version >= \"3.7\""]
+image = ["Pillow (>=8.0.0)"]
+
+[[package]]
+name = "typing-extensions"
+version = "4.13.2"
+description = "Backported and Experimental Type Hints for Python 3.8+"
+optional = false
+python-versions = ">=3.8"
+groups = ["main"]
+markers = "python_version < \"3.11\""
+files = [
+    {file = "typing_extensions-4.13.2-py3-none-any.whl", hash = "sha256:a439e7c04b49fec3e5d3e2beaa21755cadbbdc391694e28ccdd36ca4a1408f8c"},
+    {file = "typing_extensions-4.13.2.tar.gz", hash = "sha256:e6c81219bd689f51865d9e372991c540bda33a0379d5573cddb9a3a23f7caaef"},
+]
+
+[metadata]
+lock-version = "2.1"
+python-versions = "^3.8"
+content-hash = "5be578d4d6428e9a32edf0d821c8092d1a83af70283685207885d852fbaa3678"
diff --git a/pyproject.toml b/pyproject.toml
new file mode 100644
index 0000000..0aa8348
--- /dev/null
+++ b/pyproject.toml
@@ -0,0 +1,21 @@
+[tool.poetry]
+name = "passifypdf"
+version = "1.0.0"
+description = "Protect PDF by a password of your choice"
+authors = ["Nirmal Chandra <nirmal.fleet@gmail.com>"]
+readme = "README.md"
+packages = [{include = "passifypdf"}]
+
+[tool.poetry.dependencies]
+python = "^3.8"
+pypdf = "^4.3.1"
+
+[tool.poetry.group.dev.dependencies]
+coverage = "^7.0"
+
+[build-system]
+requires = ["poetry-core"]
+build-backend = "poetry.core.masonry.api"
+
+[tool.poetry.scripts]
+passifypdf = "passifypdf.encryptpdf:main"
diff --git a/requirements.txt b/requirements.txt
deleted file mode 100644
index 15f3f6c..0000000
--- a/requirements.txt
+++ /dev/null
@@ -1 +0,0 @@
-pypdf==4.3.1
\ No newline at end of file
diff --git a/setup.py b/setup.py
deleted file mode 100644
index 70c8816..0000000
--- a/setup.py
+++ /dev/null
@@ -1,16 +0,0 @@
-from setuptools import setup, find_packages
-
-setup(
-    name='passifypdf',
-    version='1.0',
-    description='Protect PDF by a password of your choice',
-    long_description='Protect PDF by a password of your choice',
-    include_package_data=True,
-    author_email='nirmal.fleet@gmail.com',
-    author='Nirmal Chandra',
-    url='https://github.com/SUPAIDEAS/passifypdf.git',
-    packages=find_packages(exclude=('tests')),
-    install_requires=[
-        'pypdf==4.3.1'
-    ]
-)
diff --git a/tests/integrationtests/test_encryptpdf_integration.py b/tests/integrationtests/test_encryptpdf_integration.py
index b11f945..7cebc00 100644
--- a/tests/integrationtests/test_encryptpdf_integration.py
+++ b/tests/integrationtests/test_encryptpdf_integration.py
@@ -1,8 +1,41 @@
+import os
 from unittest import TestCase
 
-from encryptpdf import pipeline
+from pypdf import PdfReader, PdfWriter
+
+from passifypdf.encryptpdf import encrypt_pdf
 
 
 class TestPdfIntegrationTests(TestCase):
-    def test_pipeline_integration(self):
-        self.assertEquals("awesomePdfProtection_IntegrationTest", pipeline("awesomePdfProtection_IntegrationTest"))
+    def setUp(self):
+        self.input_pdf = "test_input.pdf"
+        self.output_pdf = "test_output.pdf"
+        self.password = "strongpassword"
+
+        # Create a dummy PDF
+        writer = PdfWriter()
+        writer.add_blank_page(width=100, height=100)
+        with open(self.input_pdf, "wb") as f:
+            writer.write(f)
+
+    def tearDown(self):
+        # Cleanup files
+        if os.path.exists(self.input_pdf):
+            os.remove(self.input_pdf)
+        if os.path.exists(self.output_pdf):
+            os.remove(self.output_pdf)
+
+    def test_encrypt_pdf_integration(self):
+        # Encrypt the PDF
+        encrypt_pdf(self.input_pdf, self.output_pdf, self.password)
+
+        # Verify output exists
+        self.assertTrue(os.path.exists(self.output_pdf))
+
+        # Verify it is encrypted
+        reader = PdfReader(self.output_pdf)
+        self.assertTrue(reader.is_encrypted)
+
+        # Verify we can decrypt it
+        self.assertTrue(reader.decrypt(self.password))
+        self.assertEqual(len(reader.pages), 1)
diff --git a/tests/test_encryptpdf_example.py b/tests/test_encryptpdf_example.py
deleted file mode 100644
index 9ea4cb6..0000000
--- a/tests/test_encryptpdf_example.py
+++ /dev/null
@@ -1,8 +0,0 @@
-from unittest import TestCase
-
-from encryptpdf import pipeline
-
-
-class TestPdfExample(TestCase):
-    def test_pipeline_example(self):
-        self.assertEquals("awesomePdfProtection", pipeline("awesomePdfProtection"))
diff --git a/tests/unittests/test_encryptpdf.py b/tests/unittests/test_encryptpdf.py
index 83fc7df..d8d2aa9 100644
--- a/tests/unittests/test_encryptpdf.py
+++ b/tests/unittests/test_encryptpdf.py
@@ -1,8 +1,61 @@
 from unittest import TestCase
-
-from encryptpdf import pipeline
+from unittest.mock import patch, mock_open
+from passifypdf.encryptpdf import encrypt_pdf
 
 
 class TestPdfUnitTests(TestCase):
-    def test_pipeline(self):
-        self.assertEquals("awesomePdfProtection-UnitTest", pipeline("awesomePdfProtection-UnitTest"))
+
+    @patch('passifypdf.encryptpdf.PdfReader')
+    @patch('passifypdf.encryptpdf.PdfWriter')
+    @patch('passifypdf.encryptpdf.Path')  # Mock Path
+    @patch('builtins.open', new_callable=mock_open)
+    def test_encrypt_pdf(self, mock_file, mock_path_cls, mock_writer_cls, mock_reader_cls):
+        # Setup mocks
+        mock_path_instance = mock_path_cls.return_value
+        mock_path_instance.exists.return_value = True
+        mock_path_instance.is_file.return_value = True
+
+        mock_reader_instance = mock_reader_cls.return_value
+        mock_reader_instance.pages = ['page1', 'page2']
+        
+        mock_writer_instance = mock_writer_cls.return_value
+        
+        # Call the function
+        encrypt_pdf("input.pdf", "output.pdf", "secret")
+        
+        # Verify Path existence check
+        mock_path_cls.assert_called_with("input.pdf")
+        mock_path_instance.exists.assert_called()
+        mock_path_instance.is_file.assert_called()
+
+        # Verify PdfReader was called with the path object
+        mock_reader_cls.assert_called_with(mock_path_instance)
+        
+        # Verify pages were added
+        self.assertEqual(mock_writer_instance.add_page.call_count, 2)
+        mock_writer_instance.add_page.assert_any_call('page1')
+        mock_writer_instance.add_page.assert_any_call('page2')
+        
+        # Verify encryption
+        mock_writer_instance.encrypt.assert_called_with("secret")
+        
+        # Verify file write
+        mock_file.assert_called_with("output.pdf", "wb")
+        mock_writer_instance.write.assert_called_with(mock_file())
+
+    @patch('passifypdf.encryptpdf.Path')
+    def test_encrypt_pdf_file_not_found(self, mock_path_cls):
+        mock_path_instance = mock_path_cls.return_value
+        mock_path_instance.exists.return_value = False
+        
+        with self.assertRaises(FileNotFoundError):
+            encrypt_pdf("nonexistent.pdf", "output.pdf", "secret")
+
+    @patch('passifypdf.encryptpdf.Path')
+    def test_encrypt_pdf_is_directory(self, mock_path_cls):
+        mock_path_instance = mock_path_cls.return_value
+        mock_path_instance.exists.return_value = True
+        mock_path_instance.is_file.return_value = False
+        
+        with self.assertRaises(IsADirectoryError):
+            encrypt_pdf("directory", "output.pdf", "secret")