SEJPM
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What's the purpose of DH Parameters?
90 votes

What exactly is the purpose of these DH Parameters? These parameters define how OpenSSL performs the Diffie-Hellman (DH) key-exchange. As you stated correctly they include a field prime p and a ...

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Is Signal still more secure than WhatsApp?
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65 votes

There are still a couple of security functions, which may matter to you, which Signal does better than WhatsApp. Client-Side Fanout When you use a group chat in WhatsApp, you send your message to the ...

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How could I make the results of a yes/no vote inaccessible unless it's unanimous in the affirmative, without a trusted third party?
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37 votes

This sounds like a classic case for cryptographically secure Multi-Party Computation. The functionality to be realised using SMPC would be an AND tree-reduction which requires N-1 AND gates and has a ...

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Source code as password
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27 votes

You can use source code as password. However I'd strongly recommend against using source code as a passphrase. The reason for this is entropy. Passwords / passwphrases need to provide lots of entropy ...

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Bitlocker without TPM with both a startup USB and password?
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23 votes

This guide explains it quite well, although consider following the steps below rather than downloading and running .reg files from the internet. One can turn on Bitlocker without TPM but has to ...

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RAM Encryption. Is it possible?
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13 votes

Without adding any additional hardware, is RAM encryption possible? Sure. You can encrypt whatever you like in RAM, just like you encrypt everything else. The more interesting quesstion is "where are ...

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What does "Old" mean in "OLD_TLS_ECDHE_RSA_WITH_CHACHA20_POLY1305_SHA256"?
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12 votes

Back in the day when the ChaCha20-Poly1305 cipher suites were introduced, Google rushed them out. There was no full IETF TLS WG review nor was there any formal process involved (which isn't yet ...

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Is this RSA/AES combination good?
12 votes

No this protocol isn't safe. As already mentioned in the comments: Don't roll your own crypto. Chances are you're getting it wrong. Especially if you admit that you don't really know what you're ...

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Regenerating dhparam periodically
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11 votes

Does it increase connection security if I regenerate the dhparam files used with NGINX on our servers periodically e.g. every week? No, not significantly. DH parameters are really just a large ...

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How secure is AES-256-CBC with user provided password and initialization vector
10 votes

First off, the usual warning: Do not roll your own crypto, chances are you're getting it wrong. Now the second warning: You seem to encrypt data solely using AES-CBC, which is very dangerous, you ...

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What is the exact meaning of "Keying material"?
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9 votes

What is the exact meaning of “Keying material”? Keying material is a more general and fancy term for "secret keys of (unspecified) format, length and amount", where the "unspecified&...

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Best way to encrypt data using php - I am not sure if I doing it correctly
7 votes

There are at least two problems with this approach. Your choice of key generation Your choice of encryption mode Key Generation You're doing md5("static password") as your key. This is really bad. ...

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How secure is my software for file encryption with AES-256?
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6 votes

First: Please don't roll your own crypto. If you're doing this for production purposes I've to strongly recommend against using it. If it you want to improve your programming skills or this is a ...

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Do password managers leak information with swap memory?
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6 votes

As I've already pointed out in my previous comment, this attack has been foreseen and already countered (by most cryptography using applications). The way you do this is, you (the developer) tell the ...

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Do I need to set maximum characters length for password using bcrypt?
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6 votes

Well Dmitry is right when he says 72 characters is good. If the characters are random enough. (1.78 bits per character). You can use the approach described (security warning that password is "too ...

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Is it more secure to specify https:// in front of a domain?
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5 votes

Would I then request an insecure connection (http), get redirected to the secure https protocol by the http response, and thus making a less secure request? It depends. In all generality the ...

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Does TLS authentication encrypt username as well as password?
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5 votes

If I'm reading your question correctly, you're connecting to your VPN using a combination of TLS client authentication and username / password combination. In this case a MitM attacker can read the ...

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Securing Peer to Peer communication
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5 votes

Is there a standard way to secure peer to peer communication? Of course there is. If you want to do highly asymmetric communication (i.e. chat or chat-like communication) OTR (or Axolotl) is the way ...

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Setting up DNSsec for an exotic TLD
5 votes

.money is one of the new top level domains (TLDs), as such it (by itself) should support DNSSEC. This turns the DNSSEC support into a question of your registrar. As you noted already, it's not ...

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Is AES 256 secure enough for putting Backups to AWS or Dropbox?
5 votes

How fast can you crack AES-256? Either never (within next two centuries) or within days. AES-256 is considered incrackable by itself. Even most implementations are considered safe. (no side-channels)...

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Two VPNs — full anonymity?
4 votes

If you route your traffic throught two VPNs you'll gain a lot of anonymity. However you're not anonymous to every possible attacker, as an attacker could break both VPNs (NSA broke quite a lot VPNs), ...

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How to have client encryption without server encryption key
4 votes

First: The very first rule of cryptography: Don't roll your own crypto! Second: Why do you want to setup this service? Signal (+ OTR or Axolotl) does all this already for: It's open-source, allows ...

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Security of online storage of KeePass-like files
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4 votes

it is not safe to encrypt several files with the same key This statement isn't fully true. It is indeed not a good practice to encrypt many files using the same (data) key, but it is still absolutely ...

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Ensure that a file can only be decrypted after a specific date
4 votes

I'm not fully sure if this paper about time-lock encryption has been inspired by this discussion but it would be the most formal solution to the question "How to build time-lock encryption?", which is ...

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Why is validating the integrity of the plaintext necessary in addition to validating the integrity of the cipher text?
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3 votes

What does this additional signature component add to the authenticity of the message? Actually I think you got it reverse here. The ECDSA signature was there first. It turned out it wasn't sufficient....

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What is a secure DNSKEY bit length and usage time?
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3 votes

So is it correct to assume that these DNSKEY's are unsafe to use? The 512-bit ones definitely, because they can be factored within such a short time frame. The 1024-bit ones should be safe because ...

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Generating many keys: how many CSPRNGs to use?
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3 votes

What you want for your key(s) is to be completely unpredictable. There are now three cases to distinguish which really depend on your "secure random" class / object. It starts with high entropy and ...

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Shortest SHA-3 output
3 votes

The SHA-3 standard is both old and new. It's "old" because the competition for selecting the SHA-3 hash function began back in 2009 and we know since 2012 that Keccak won. On the other hand, the ...

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How to authenticate users?
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3 votes

There are a few ways to do this. You can come down to the following statement: For authentication you can only use something the user knows, has or is. As you're in a file-encryption scenario, this ...

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aWallet Password Manager
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2 votes

Please note: This post actually answers the question(s) in the question and doesn't comment (much) on the security of aWallet. I suggest you visit the Crypto.SE version of this question for a review ...

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