# Encryption and Decryption of PDFs

> Please see the note in the [installation guide](installation.md)
> for installing the extra dependencies if interacting with PDFs that use AES.

## Encrypt

Add a password to a PDF (encrypt it):

```python
from pypdf import PdfReader, PdfWriter

reader = PdfReader("example.pdf")
writer = PdfWriter()

# Add all pages to the writer
for page in reader.pages:
    writer.add_page(page)

# Add a password to the new PDF
writer.encrypt("my-secret-password")

# Save the new PDF to a file
with open("encrypted-pdf.pdf", "wb") as f:
    writer.write(f)
```

## Decrypt

Remove the password from a PDF (decrypt it):

```python
from pypdf import PdfReader, PdfWriter

reader = PdfReader("encrypted-pdf.pdf")
writer = PdfWriter()

if reader.is_encrypted:
    reader.decrypt("my-secret-password")

# Add all pages to the writer
for page in reader.pages:
    writer.add_page(page)

# Save the new PDF to a file
with open("decrypted-pdf.pdf", "wb") as f:
    writer.write(f)
```
