When you create an encrypted TrueCrypt 7.1a volume (or drive), and store your pdf files in it, you are no longer in the realm of closed source, minimally tested, minimally audited security software with possible backdoors or other significant vulnerabilities. You are instead skirting on the very edges of state-of-the-art, tried and tested, open source, multiple level encryption techniques which have a deep history and reputation for its security properties. The reputations, lifework and elite cryptographic skills of individuals and whole security organizations have gone into producing or auditing this piece of software and promoting its use. In our opinion, there is no better way to securely store your files. We do not recommend you use newer derivative versions of the software such as VeraCrypt, as newer is not always better, and in our case due to our unique process, we believe they offer no additional benefit.
TrueCrypt file encryption arguably has the deepest history of all well known encryption systems. This is looking from the perspective of not only the research and development side of the software but also from the real world case studies of its use. Government policing organizations have spent months to years trying to unlock content secured using it without success and this can be seen in numerous law cases. The software has a history of being recommended by people of high repute who have themselves risked their lives to reveal shortcomings in public security and personal privacy. There possibly exists no other piece of security software that has been (or will ever be) audited and reviewed as many times and as intensely as has been the case with TrueCrypt 7.1a. The software has all the notable experiences of being praised, and widely used, and thoroughly audited, and then discredited (citing minor program flaws as the reason) and suddenly being advised against. We believe this unique history equates to incontestable security although others less informed may not see it this way.
What does all of this mean in layman’s terms? It means that your password protected TrueCrypt file is absolutely inaccessible without the single correct password used to lock it.
If you have any doubt as to the power of this software tool then do remember that you don’t have to rely on it exclusively to protect your bitcoin information. You will always be using the password protected pdf file to protect your information anyway, so all you have to do is use a different password for the TrueCrypt file as the one used to secure the pdf file. An easy and reliable way to do this is to use ‘QuickHash-Windows-v2.6.9.2’ to convert (via SHA512), your pdf password to your TrueCrypt password and this must be done offline after downloading the program from https://quickhash-gui.org/download/quickhash-v2-6-9-2-for-windows/. You do this every time you want to access it.
If you do all this, you only need to ever remember one single password since the TrueCrypt password is always obtained from the one way conversion of the pdf file password. It is impossible for anyone to find out the pdf password by working backwards from the TrueCrypt password. If after reading all the above you still for some reason don’t want to use TrueCrypt, and for you it is either something else or nothing at all, then you should instead use the encrypted electrum wallets as the sole storage format for your bitcoin keys (secured by the most secure 26 to 32 character password). This means you should skip storing your seeds onto the secured pdf file. This is recommended because a standalone encrypted wallet file is easier to create and transact with than a standalone password protected pdf file.
NOTE: ‘QuickHash-Windows-v2.6.9.2’ don’t have a setting to hide your character input when you type in your password but an easy workaround is to drag half of the ‘QuickHash-Windows-v2.6.9.2’ screen to the left side of your desktop past the edge to hide your character input and then enter the password. If you want to copy the entered text onto your clipboard without looking at it (so you can paste it somewhere later), you can first press both [Ctrl+A] then, both [Ctrl+C]. The other thing you can do to protect your passwords is to place your whole computer, including yourself, under a covering or inside a double layered Faraday tent.