When people search for types of encryption, they are usually trying to understand which security model fits a real-world workflow. The short answer is that there is no single encryption category for every job. Modern systems use different approaches depending on whether they need fast file protection, secure key exchange, password-based document locking, or tamper detection.
For document protection and encrypted storage, the two most important concepts are symmetric encryption and asymmetric encryption. It is also important to separate hashing from encryption, because those terms often get mixed together in marketing copy and search results.
Symmetric encryption
Symmetric encryption uses the same secret to encrypt and decrypt data. It is usually the best choice for protecting files, archives, and storage containers because it is fast and efficient. AES is the best-known example. If you are encrypting a PDF, a ZIP-like container, or a file stored on disk, symmetric encryption is typically doing the heavy lifting.
Asymmetric encryption
Asymmetric encryption uses a public key and a private key. One key encrypts, the other key decrypts. This model is excellent for identity, key exchange, and digital trust, but it is usually not the fastest way to encrypt large files directly. In many secure systems, asymmetric encryption is used to protect the key, while symmetric encryption protects the file itself.
Hashing is not encryption
Hashing is a one-way transformation, not a reversible encryption method. A secure hash helps verify integrity, compare values safely, or support authentication flows. If you can decrypt something back to the original data, it is encryption. If you cannot reverse it, it is probably hashing.
Which encryption PDFEncrypted uses
On PDFEncrypted, there are two main protection models in the current product codebase:
- Encrypted PDFs: the site applies PDF encryption with 128-bit or 256-bit settings through the PDF security flow, with 256-bit as the default option.
- Encrypted containers (.pfe): the site encrypts container payloads with AES-256-GCM and derives the key from the user password with scrypt.
That means PDFEncrypted uses strong symmetric encryption both for direct PDF protection and for multi-file secure containers, while also using modern authenticated encryption for the container format.
Which type of encryption should you use?
If you are protecting a single PDF, PDF encryption is usually the cleanest choice. If you need to secure multiple files together, keep them in one bundle, or support an offline unlock workflow, an encrypted container is often the better fit. The right choice depends on how many files you have, who needs access, and how much control you want over the sharing experience.
Bottom line
The most useful way to think about encryption is not “which algorithm sounds strongest,” but “which model matches the job.” Symmetric encryption protects files efficiently. Asymmetric encryption helps manage trust and identity. Hashing verifies integrity. On PDFEncrypted, the practical user-facing choices are secure PDF encryption and AES-256-GCM encrypted containers.