Initial commit: SecPaste encrypted pastebin client

SecPaste is a Python library and CLI tool for sharing encrypted content via
public pastebin services with zero-knowledge architecture.

Features:
- Pluggable crypto backends (AES-256-GCM, ChaCha20-Poly1305, Kyber-768)
- Pluggable pastebin providers (dpaste.com, extensible)
- URL fragment key storage (key never sent to server)
- Both CLI and library usage
- Post-quantum cryptography support (experimental)

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

setup.py

@@ -0,0 +1,47 @@
+#!/usr/bin/env python3
+"""Setup script for SecPaste."""
+
+from setuptools import setup, find_packages
+from pathlib import Path
+
+# Read README
+readme = Path(__file__).parent / 'README.md'
+long_description = readme.read_text() if readme.exists() else ''
+
+setup(
+    name='secpaste',
+    version='0.1.0',
+    description='Encrypted pastebin client with pluggable cryptography',
+    long_description=long_description,
+    long_description_content_type='text/markdown',
+    author='SecPaste Contributors',
+    url='https://github.com/yourusername/secpaste',
+    packages=find_packages(),
+    install_requires=[
+        'cryptography>=41.0.0',
+        'requests>=2.31.0',
+    ],
+    extras_require={
+        'pqc': ['liboqs-python>=0.8.0'],
+    },
+    entry_points={
+        'console_scripts': [
+            'secpaste=secpaste.cli:main',
+        ],
+    },
+    python_requires='>=3.8',
+    classifiers=[
+        'Development Status :: 3 - Alpha',
+        'Intended Audience :: Developers',
+        'License :: OSI Approved :: MIT License',
+        'Programming Language :: Python :: 3',
+        'Programming Language :: Python :: 3.8',
+        'Programming Language :: Python :: 3.9',
+        'Programming Language :: Python :: 3.10',
+        'Programming Language :: Python :: 3.11',
+        'Programming Language :: Python :: 3.12',
+        'Topic :: Security :: Cryptography',
+        'Topic :: Internet :: WWW/HTTP',
+    ],
+    keywords='pastebin encryption crypto privacy security',
+)