Add option to save backups to a PDF file

Pipfile

@@ -6,11 +6,13 @@ name = "pypi"
 [dev-packages]
 
 [packages]
-rncryptor = "==3.2.0"
+rncryptor = "==3.3.0"
 bpylist = "==0.1.4"
 click = "==6.7"
 pyqrcode = "==1.2.1"
-pycryptodome = "==3.9.1"
+pypng = "==0.0.20"
+reportlab = "==3.5.53"
+pillow = "==7.2.0"
 
 [requires]
 python_version = "3.7"

README.md

@@ -37,6 +37,14 @@ pipenv run python decrypt_otpauth.py decrypt_backup --encrypted-otpauth-backup <
 pipenv run python decrypt_otpauth.py decrypt_account --encrypted-otpauth-account <path to your OTP Auth account>
 ```
 
+## Outputting PDF
+
+If you'd prefer to store analog backups (e.g. by printing the QR codes and putting them in a safe), both decryption commands support an option to output a PDF file:
+
+```
+pipenv run python decrypt_otpauth.py decrypt_backup --encrypted-otpauth-backup <otp_auth_backup_path> --pdf-out <pdf_path>
+```
+
 ## Demo
 
 The project contains two OTP Auth exports for demo purposes:

decrypt_otpauth.py

@@ -2,6 +2,7 @@
 import click
 import getpass
 import hashlib
+from io import BytesIO
 
 from enum import Enum
 from urllib.parse import quote
@@ -16,6 +17,9 @@
 from rncryptor import RNCryptor
 from rncryptor import bord
 
+import PIL
+from reportlab.platypus import SimpleDocTemplate, Image, BalancedColumns, Paragraph, Flowable
+from reportlab.lib.styles import getSampleStyleSheet
 
 class Type(Enum):
     Unknown = 0
@@ -196,6 +200,35 @@ def render_qr_to_terminal(otp_uri, type, issuer, label):
     click.echo(qr.terminal(quiet_zone=4))
     click.echo("")
 
+def write_accounts_to_pdf(accounts, pdf_path):
+    class CaptionedQr(Flowable):
+        def __init__(self, img, caption):
+            self.img = img
+            self.caption = caption
+            self.width = 120
+            self.img_height = 120
+            self.height = 160
+            self.caption_line_padding = 10
+        def draw(self):
+            self.canv.drawInlineImage(self.img, 0, 0, self.width, self.img_height)
+            textobj = self.canv.beginText(0, -self.caption_line_padding)
+            # Decide whether to wrap to next line after writing each char
+            for char in self.caption:
+                textobj.textOut(char)
+                if textobj.getX() > self.width:
+                    textobj.moveCursor(0, self.caption_line_padding)
+            self.canv.drawText(textobj)
+
+    pdf = SimpleDocTemplate(pdf_path)
+    flowables = []
+    for index, account in enumerate(accounts):
+        b = BytesIO()
+        qr = pyqrcode.create(account.otp_uri(), error="L")
+        qr.png(b, 5)
+        caption = f'{account.issuer} - {account.label}'
+        img = PIL.Image.open(b)
+        flowables.append(CaptionedQr(img, caption))
+    pdf.build([BalancedColumns(flowables, 3)])
 
 @click.group()
 def cli():
@@ -207,7 +240,10 @@ def cli():
               help="path to your encrypted OTP Auth account (.otpauth)",
               required=True,
               type=click.File('rb'))
-def decrypt_account(encrypted_otpauth_account):
+@click.option('--pdf-out',
+              help="path to output an PDF file instead of printing to the terminal",
+              required=False)
+def decrypt_account(encrypted_otpauth_account, pdf_out):
     # Get password from user
     password = getpass.getpass(f'Password for export file {encrypted_otpauth_account.name}: ')
 
@@ -230,7 +266,10 @@ def decrypt_account(encrypted_otpauth_account):
         click.echo(f'Encountered unknow file version: {archive["Version"]}')
         return
 
-    render_qr_to_terminal(account.otp_uri(), account.type, account.issuer, account.label)
+    if not pdf_out:
+        render_qr_to_terminal(account.otp_uri(), account.type, account.issuer, account.label)
+    else:
+        write_accounts_to_pdf([account], pdf_out)
 
 
 def decrypt_account_11(archive, password):
@@ -266,7 +305,10 @@ def decrypt_account_12(archive, password):
               help="path to your encrypted OTP Auth backup (.otpauthdb)",
               required=True,
               type=click.File('rb'))
-def decrypt_backup(encrypted_otpauth_backup):
+@click.option('--pdf-out',
+              help="path to output an PDF file instead of printing to the terminal",
+              required=False)
+def decrypt_backup(encrypted_otpauth_backup, pdf_out):
     # Get password from user
     password = getpass.getpass(f'Password for export file {encrypted_otpauth_backup.name}: ')
 
@@ -289,9 +331,12 @@ def decrypt_backup(encrypted_otpauth_backup):
         click.echo(f'Encountered unknow file version: {archive["Version"]}')
         return
 
-    for account in accounts:
-        render_qr_to_terminal(account.otp_uri(), account.type, account.issuer, account.label)
-        input("Press Enter to continue...")
+    if not pdf_out:
+        for account in accounts:
+            render_qr_to_terminal(account.otp_uri(), account.type, account.issuer, account.label)
+            input("Press Enter to continue...")
+    else:
+        write_accounts_to_pdf(accounts, pdf_out)
 
 
 def decrypt_backup_10(archive, password):