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I am using a non-SSD drive: Western Digital Black 1TB. Windows XP (please don't judge why I'm still using XP).

I am using Truecrypt.

Q1. If I were to create a system partition drive C: and 2-3 non-system partition drives D:, E:, F:, etc. using a good password, is my data pretty much secure as long as nobody knows my password? Are there any flaws in my Truecrypt Security Setup? It shouldn't be less secure than "Whole Disk Encryption" since we are encrypting every partition?

Q2. If I had a weak password, and changed my password to a more secure password, is my data still secure? (As long as any "adversary" doesn't have the original TC Rescue disk or copy of your original Volume)

Q3. SSD drives, I believe, are different because if you were to write data on the SSD drive BEFORE you created an encrypted partition, that data may possibly be retrieved. However, if you created encrypted partitions first, and wrote data to your encrypted SSD partitions AFTER they've been encrypted, is the data safe as long as nobody has the password?

-Source https://andryou.com/truecrypt/docs/changing-passwords-and-keyfiles.php

Thanks!

EDIT

Mark's Answer is the most specific in terms of what actual real threats So I want to address them. I am NO expert so please correct me if I am wrong.

So in other words, nobody has my keyfiles, copies of my vol or password (which is very secure).... it should still be safe... unless I am missing something

I'm also switching to VeraCrypt but I don't know how secure it is in terms of TRUST and REPUTATION in comparison to Truecrypt (which is very trustworthy in my opinion)

BTW anyone can answer, lot of experts on this forum... I'm no expert :) so would love it if someone can pt out that I'm missing something

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FINAL EDIT #3- Question for Forest

Forest, Your answers are SPOT ON and very specific to the questions i've asked. Thank you for listening and answering very specifically. I believe you answered my question with certainty but I wanted to confirm this with you.

In other words, If Nobody has access to my computer, If my computer has no malware or other vulnerabilities... then....

In regards to the safety of my encrypted data on my non ssd hard drives Black WD Black Caviar 1 TB.

If I were to sell my Hard drive with all my partitions encrypted using TC with a very good password, my data would be pretty much safe and it would be very very hard to access my data without my password.

If My hard drive was stolen, it would be similar.

Is this about correct?

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    Keep in mind that Windows XP is no longer supported - meaning that as far as you know, there are huge security holes in the OS itself. Your security strategy is pretty much null-and-void if someone can just remotely download a copy of the drive and keylog your password. – Cowthulhu Jan 22 '18 at 21:05
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    @Cowthulhu Perhaps he is using it on an airgapped system. Still not ideal, but I could think up a few threat models where Windows XP would not be detrimental. – forest Jan 23 '18 at 1:42
  • @forest That's completely fair. I figured it would be relevant to point out given the OP didn't give any details on how the system was set up, but you could be absolutely right. – Cowthulhu Jan 23 '18 at 15:22
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I am using a non-SSD drive: Western Digital Black 1TB. Windows XP (please don't judge why I'm still using XP).

OK, I won't judge, but I will say that Windows XP (or any other equally vulnerable operating system) will only provide you with data at rest security. That is, when the system is powered off, the encryption is as secure as the underlying encryption and the key. An attacker with physical or network access to the computer can violate integrity and confidentiality without needing to break the encryption itself.

Q1. If I were to create a system partition drive C: and 2-3 non-system partition drives D:, E:, F:, etc. using a good password, is my data pretty much secure as long as nobody knows my password? Are there any flaws in my Truecrypt Security Setup? It shouldn't be less secure than "Whole Disk Encryption" since we are encrypting every partition?

If you define secure as providing data at rest security, then yes, it is as secure as your password. Do note that the presence of a hidden volume may be revealed due to a bug in TrueCrypt. Of course, even if you encrypt every partition, the bootloader itself still must be unencrypted. This makes it vulnerable to "evil maid attacks", where someone with the ability to write to privileged locations on the disk replaces the bootloader with a malicious version to steal your password. This requires the attacker have, e.g., physical or privileged local access, and it will only violate confidentiality at the next reboot. Assuming no one has tampered with your disk and your password is strong, it is secure.

Q2. If I had a weak password, and changed my password to a more secure password, is my data still secure? (As long as any "adversary" doesn't have the original TC Rescue disk or copy of your original Volume)

Yes it is. The way TrueCrypt (and many other disk encryption utilities that encrypt large amounts of data) work is by creating a master key and encrypting the drive with it. This master key is generated completely randomly and is not influenced by your password choice. The master key is then encrypted with your password, and the encrypted master key is stored on the disk. If your password is weak, it becomes easier to decrypt the master key, and then use it to decrypt the rest of the drive. When you change your password, you are not changing the master key itself. Rather, you are decrypting it with your weak password, then re-encrypting it with your new, strong password. The newly-encrypted master key is written over the previous, weakly-encrypted master key, making it unrecoverable. As long as no copies of this previous, weakly-encrypted master key are recoverable (through the recovery disk as you mentioned, or through SSD wear leveling), it cannot be retrieved.

Q3. SSD drives, I believe, are different because if you were to write data on the SSD drive BEFORE you created an encrypted partition, that data may possibly be retrieved. However, if you created encrypted partitions first, and wrote data to your encrypted SSD partitions AFTER they've been encrypted, is the data safe as long as nobody has the password?

The thing that makes SSDs a bit strange for encryption is wear leveling, which makes it impossible to intentionally overwrite specific data. The SSD's internal controller manages all writes and does not let the operating system control it directly. While you are correct in that there is no issue with writing to an encrypted partition on an SSD, the real issue is different. There are two issues, actually:

  • Wear leveling prevents the operating system from overwriting specific data, causing previously-written contents to persist. This can be an issue if you set a weak password and later switch to a stronger one. The VeraCrypt documentation explains this. TRIM, if enabled, is a way to tell the SSD controller to securely overwrite and zero sectors that are no longer in use.
  • TRIM can reveal to an observer what sectors are unused. This is unfortunate because TRIM can make the former issue less problematic. TRIM is designed to improve performance and allows secure deletion of unused data. While not an obvious issue (after all, the used sectors are still encrypted, and the unused ones are just zeros), it does give away the structure of your filesystem. This is described more in an excellent blog post.

Do I have to Turn on AES-NI? or is it default? so am I secure with default CPU settings or do I have to do something

AES-NI is a set of CPU instructions for doing AES encryption in hardware. It is designed to improve the performance of encryption, but it also has the benefit of creating side-channel resistance. A side-channel attack against AES is usually a cache attack. This involves running a malicious program on your computer that listens very closely to nanosecond-level delays when accessing data in the CPU cache in clever ways to determine what the AES key is. AES-NI prevents this by not using the cache. Since you say you are using Windows XP, you hopefully are not in a situation where a malicious process is in the position to run on your computer, or it has far better ways to get your key than a side-channel attack. In other words, a side-channel attack is an active attack against running encryption, but it cannot violate data at rest security.

TrueCrypt will use AES-NI by default if it is available.

I'm also switching to VeraCrypt but I don't know how secure it is in terms of TRUST and REPUTATION in comparison to Truecrypt (which is very trustworthy in my opinion)

It is based directly off of TrueCrypt and, like the former, has been audited. The source code is entirely open source. While some design decisions it has made are, in my opinion, kind of silly, the core of VeraCrypt is both secure and trustworthy. Continuing to use TrueCrypt opens you up to several unfixed issues which, of course, were not fixed since there are no more developers to fix them. This includes code execution vulnerabilities and some minor weaknesses in the crypto (bad random number generation, for example). Additionally, TrueCrypt uses a very low number of PBKDF2 iterations (usually 1000). Each iteration makes it harder to crack a password by making it take longer to derive the key from the plain password. VeraCrypt uses a variable number of iterations, often exceeding 100,000. For a very strong password, this does not matter.

To summarize, you are using a non-SSD drive on an insecure operating system but are using a strong password. This provides you with data at rest security. No one, should they get their hands on your disk, will be able to decrypt the contents without the password. The only way they could obtain the password is by attacking your computer with malware or exploits, or by tampering with your disk so that, next time you boot it up, you boot into a malicious bootloader. As long as your threat model only cares about data at rest security (e.g. you're using this on an airgapped PC), you should be fine.

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    Forest, Your answers are SPOT ON and very specific to the questions i've asked. Thank you for listening and answering very specifically. I believe you answered my question with certainty but I wanted to confirm this with you. (I have to break this into 2 comments.......) – Starzzzzz Jan 23 '18 at 4:21
  • In other words, If Nobody has access to my computer, If my computer has no malware or other vulnerabilities... then.... In regards to the safety of my encrypted data on my non ssd hard drives Black WD Black Caviar 1 TB. If I were to sell my Hard drive with all my partitions encrypted using TC with a very good password, my data would be pretty much safe and it would be very very hard to access my data without my password. If My hard drive was stolen, it would be similar. Is this about correct? – Starzzzzz Jan 23 '18 at 4:21
  • @Starzzzzz Precisely! As long as your password is strong enough and all sensitive data was written to the encrypted partition, your data is completely safe. If the answer was good enough, please mark the question as answered. :) – forest Jan 23 '18 at 4:24
  • sorry i'm new, i'm trying to figure out how to accept an answer, I added a "plus" / positive on your answer.... dunno if tha did it .. thanks agen Forest! – Starzzzzz Jan 23 '18 at 7:12
  • @Starzzzzz, there should be a grey checkmark underneath the answer score. Clicking that will turn it green and accept the answer. – Mark Jan 26 '18 at 23:16
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From the truecrypt sourceforce page -

WARNING: Using TrueCrypt is not secure

You should download TrueCrypt only if you are migrating data encrypted by TrueCrypt.

You are using an unsupported encryption program with known flaws with an unsupported operating system.

At the very least look at VeraCrypt - which is a fork of the TrueCrypt codebase which has fixed known flaws and offers several improvements.

  • Two of the known flaws are attacks on the volume-creation process (one requires an unusual configuration of Windows, and the other requires the attacker to control one of your keyfiles and know the others). A third attack involves corrupting the volume header with a complexity of 2^32 (doable in theory, but in practice, requires the victim to enter their password 2^32 times). The only serious attack is a cache-timing attack on AES, which can be mitigated by using a computer that supports the AES-NI instructions. – Mark Jan 22 '18 at 23:48
  • I have a i5-2500K CPU, which I believe supports the AES-NI instructions. So it seems like it mitagates the only seriuos attack since the CPU supports the AES-NI instructions. ark.intel.com/products/52210/… " Intel® AES New Instructions Yes " tomshardware.co.uk/forum/334844-28-2500-features-missing "2500 or 2500K? The 2500K doesn't have VT-d. My own 2500K DOES have the other features though." So in other words, nobody has my keyfiles, copioes of my vol or pasword (which is very secure).... it shoudl still be safe – Starzzzzz Jan 23 '18 at 0:03
  • BTW Mark- Do I have to Turn on AES-NI? or is it default? so am I secure with default CPU settings or do I have to do something........... I'm also switching to VeraCrypt but I dont know how secure it is in terms of TRUST and REPUTATION in comparison to Truecrypt (which is very trustworthy in my opinion) – Starzzzzz Jan 23 '18 at 0:13
  • @Starzzzzz It is more secure than TrueCrypt, not only because it fixes a few nasty bugs, but because it uses more secure cryptographic defaults. As for AES-NI, it speeds up crypto operations and, as Mark says, mitigates cache-timing attacks. If you are on Windows XP though, you probably do not care about cache-timing attacks... – forest Jan 23 '18 at 1:44

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