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1

I suppose I'll indulge this. One solution to something like this would be to have a multi part key like bitcoins so-called "multisig keys" held in different legal jurisdictions.


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The expiration date of subkeys is stored in a special kind of signature issued by the primary master key on the subkey. With other words, if you change the expiration date, no private keys are changed at all. If you can restore the public key later (for example, fetching it from the key server network), you're fine.


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Here are some general considerations regarding bigger architecture in case more servers could be used to reduce attack surface. In the above scenario, if the single server is compromised, it may reveal sensitive data over period of time when admin users are logging-in. There could be two web servers - one for clients and one for admins There could be ...


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Using a symmetric password-based encryption scheme on the keys. Where you have to "enter your passphrase" before you are allowed to use the key. Since the passphrase is used to decrypt the actual key. Most of the security concerns about the usage of passphrases are discussed here: Security of passphrase-protected private key


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I am aware of the option, white-box cryptography. Essentially, keys are embedded a specific implementation of the crypto algorithm. White-box techniques are typically hardended by code/data obfuscation, which makes debugging more difficult.


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Regarding the general managment of private/public keys, there are already other answered questions here on SE: What is the best practice: separate ssh-key per host and user VS one ssh-key for all hosts? and What's the common pragmatic strategy for managing key pairs? Regarding AWS specific details: you can and should create your own key pairs outside of AWS ...


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Consider newbie pgp-user, a person who just heard about PGP. If that person receives a signed by whatsoever PGP - he will consider the message as fully trusted and signed and so on. This would create a false sense of security.


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MD5 works perfectly fine for ensuring a file hasn't been altered. Where it (and SHA) is "bad bad bad" is for hashing passwords. The reason? MD5 and SHA are designed to be fast, which makes them easy to brute force with a GPU. For passwords, use a slow hashing algorithm like bcrypt with a random per user salt. In my use case, I am granting access to ...


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Certificate Pinning is another commonly used control against Data-in-transit attacks. The TLS handshake never starts if the client doesn't receive a Public Key that is within the client's (the mobile app) known Pin List. I used Cert Pinning as a compliment to payload encryption. Perhaps the following are becoming the base standard for sensitive mobile app ...


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If you're (somewhat) sure that the key is not compromised, I'd simply create a bunch of subkeys and move whatever keys you want to smartcards or other offline places. Adding subkeys is easily possible by using gpg[2] --edit-key and the addkey commands. The usage flags are stored in a signature subpacket, so changing them does not change the key (with ...


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You can solve this by using deployment tools such as Chef or Ansible. Particularly about Chef, you have the Chef Push to push whatever cookbook (i.e. the key files) to all the nodes (i.e. the servers).


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Why use dedicated SSH keys for different hosts (like GitHub)? Answer: Revocation. When you lose an SSH key, you have to revoke it on everything it had access to. If you use the same key on GitHub as you use to SSH in to your personal web hosting, you have to remove the key from both places. One key per service means none of your other keys are impacted by ...


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The GitHub advice is possibly over stating the risk. Using the same ssh key on multiple systems has nothing like the risks associated with having the same password on multiple systems. However, there are some other factors to consider which may result in someone having more than one ssh key. The most obvious reason to have more than one ssh key relates to ...



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