pdf-encryption
Apache-2.0 PDF toolkit CLI in Python: merge, split, extract, rotate, PDF→images, images→PDF, create, text/tables, compress, encrypt, metadata, watermark, OCR, Office→PDF
Free MIT PDF library: one Rust core with bindings for Python, C#/.NET, Node.js, Go, PHP, Ruby, Java, Swift and Delphi. PDF/A, PDF/UA, PAdES signatures, AES-256, forms, rendering.