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Sep
25
answered what fields should I encrypt in a database containing user information?
Sep
25
comment Is it bad that my ed25519 key is so short compared to a RSA key?
Note that P != NP is about asymptotic behaviour, so it would not be proven even if there was, at some point, a symmetric encryption algorithm with keys of a given, specific size n and ideal security (i.e. no better attack than brute force). For it to demonstrate that P != NP, the proof would have to be valid for arbitrarily large values of n.
Sep
24
awarded  Enlightened
Sep
24
awarded  Nice Answer
Sep
24
comment Encryption and Signature with same RSA private key
There is no "ephemeral RSA" cipher suite in SSL, where the server would generates a new encryption-only RSA key pair to be used for key exchanged. There used to be such a mechanism, but it was to support strict pre-2000 US export regulations, and the ephemeral RSA key was hopelessly weak by being constrained to be of 512 bits or less. Modern clients and servers do not support that (or at least should not support that).
Sep
24
comment Encryption and Signature with same RSA private key
The server's public key is in the server's certificate, which is signed by a certificate authority. If the CA also uses a RSA key, then you have what you ask for: a RSA key used for encryption, authenticated with a signature relative to another RSA key (the CA key).
Sep
24
comment Encryption and Signature with same RSA private key
The public part of the ephemeral DH key pair is sent without encryption (this is a logical necessity: the point of DH is to establish a shared secret that will be used to encrypt the data).
Sep
24
comment Correct way of encrypting user passwords
If someone can encrypt passwords with the "master key" then that someone has the key, and you lost. A 256-bit master key, properly generated, cannot be brute-forced. A higher iteration count only turn an utterly impossible attack into another utterly impossible attack, so there is no actual gain.
Sep
24
answered Is it bad that my ed25519 key is so short compared to a RSA key?
Sep
24
answered Encryption and Signature with same RSA private key
Sep
24
answered Correct way of encrypting user passwords
Sep
23
answered Why is secp521r1 no longer supported in Chrome, others?
Sep
23
answered When I connect my PC to a network, what (meta) information can the router/admin see that identifies my PC?
Sep
23
comment Hashing user passwords via Javascript client-side versus server-side hashing?
@Gray: using the binary output of SHA-256 incurs the risk of the bcrypt implementation to interpret the bytes as a string and stop at the first byte of value 0. IF your bcrypt implementation can process arbitrary binary inputs with bytes of value 0, then using the raw SHA-256 output should be exactly as secure as using the Base64-encoded SHA-256 output (not stronger, not weaker).
Sep
23
answered Certificate - Digital fingerprint vs Signature
Sep
23
comment Hashing user passwords via Javascript client-side versus server-side hashing?
Normally, the expression "password-equivalent" should be convincing enough. If what the client browser sends grants access, and that value is exactly what you store in the database, then your database contents are full of access-granting tokens that can be simply used. The crucial point to understand is that you send Javascript to the attacker's browser, but nothing forces the attacker to run your Javascript.
Sep
23
answered Hashing user passwords via Javascript client-side versus server-side hashing?
Sep
23
answered Can a BIOS or UEFI infection transfer to other storage drives without the OS presence?
Sep
22
comment Is a keyboard with updatable firmware a security risk?
A hardware-based keylogger could be planted in any keyboard. For an attack that does not involve a screwdriver (e.g. something that happens discreetly when you plug the keyboard in a malware-infected machine), the keyboard is theoretically vulnerable if it has a firmware that can be updated over the wire, and that covers about all USB keyboards nowadays (at least you cannot make sure that there is no update procedure in a given keyboard). The "Ducky Mini" is not intrinsically worse here. A PS/2 (non-USB) keyboard is probably safe, but modern machines may not have a PS/2 port.
Sep
22
answered Is a keyboard with updatable firmware a security risk?