AES Benchmark¶

Apple-to-apple performance comparison between zerodep AES implementations and pycryptodome (C extension).

Implementations¶

The AES module is a single file (aes.py) with automatic backend dispatch: OpenSSL (via ctypes) is used by default when libcrypto is available; a pure-Python fallback activates otherwise.

Modes Tested¶

Data Sizes¶

ECB Encryption (Mean)¶

ECB Decryption (Mean)¶

CBC Encryption (Mean)¶

CBC Decryption (Mean)¶

CTR Encryption (Mean)¶

GCM Encryption (Mean)¶

GCM Decryption (Mean)¶

Key Takeaways¶

• OpenSSL ctypes is the default backend and consistently outperforms pycryptodome's C extension: 1.1--1.5x faster in ECB/CBC for small-to-medium data, scaling up to 6.9x faster for large CBC decryption. In GCM mode the advantage is most pronounced at 5.3--6.3x faster. All of this requires zero pip dependencies -- only a system-installed libcrypto.
• Pure Python fallback is ~10x slower than pycryptodome for small messages and 300--500x slower for medium/large data. This is expected for interpreted Python vs compiled C and serves as a last-resort fallback when no native library is available.
• GCM mode in pure Python includes GF(2^128) multiplication, making it the slowest pure-Python mode (~250 us for 13 bytes vs ~82--85 us for ECB/CBC). The OpenSSL backend shows no such penalty.
• pycryptodome is fast (C extension) but requires a compiled dependency via pip. OpenSSL ctypes matches or beats it in every scenario tested.

Run It Yourself¶

pip install pytest pytest-benchmark pycryptodome
pytest aes/test_aes_benchmark.py --benchmark-only -v

Latest CI Results¶

Updated automatically on each release via Benchmark CI.