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seen Dec 15 at 15:38

Dec
24
awarded  Nice Answer
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22
revised Future proof encryption possible in theory?
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Dec
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revised Future proof encryption possible in theory?
added 167 characters in body
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revised Future proof encryption possible in theory?
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revised Future proof encryption possible in theory?
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comment Future proof encryption possible in theory?
... But not with the same key lengths or padding schemes that we used in the 70s. It isn't just the conceptual algorithm, but the specific implementation, that must stand the test of time.
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revised Future proof encryption possible in theory?
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answered Future proof encryption possible in theory?
Dec
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comment X.509 certificate attack (small sha1 private key)
In the example you showed, the modulus and exponent of the public key for the certificate itself are clearly labelled under "RSA Public Key:" as "Modulus" (very large string of bytes) and "Exponent" (65537).
Dec
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comment Is the date that a password was last changed useful to an attacker?
True all; this is the kind of thing I wanted to tease out. If the account were still vulnerable given the same vectors with or without the data in question, then that data isn't "sensitive". But, it remains to be demonstrated that this information would provide no significant advantage in any situation where it could be accessed.
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revised Is there an asymmetric encryption algorithm that maintains the length of the plaintext?
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revised Is the date that a password was last changed useful to an attacker?
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comment X.509 certificate attack (small sha1 private key)
The modulus, N, is the majority of the "public key" (the exponent used for encryption with the public key is typically small). N is a number that is the product of two large prime numbers. Encryption is performed by turning the message into an integer number less than N, raising that message integer to the power of the exponent, then modulo dividing by N. The resulting number is the ciphertext. The ciphertext is decrypted by raising it to a different exponent, but then dividing by the same modulus to obtain the plaintext. See en.wikipedia.org/wiki/RSA_(algorithm)
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revised How can I explain the concept of public and private keys without technical jargon?
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asked Is the date that a password was last changed useful to an attacker?
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comment X.509 certificate attack (small sha1 private key)
@ewanm89 - Yes, quantum computers are the looming threat to RSA and most other large-number reverse-math problems. As you say, however, we currently have computers with enough qubits to handle N-values from 1 to 16. Practically speaking, most long RSA key values are quite safe for the foreseeable future.
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comment Are there more modern password hashing methods than bcrypt and scrypt?
@Rook - To add even more detail, scrypt requires either variably exponential memory and exponential time, or constant memory and variably exponentially more time. Basically, you can crack N rounds of an H-bit scrypt hash function in 2^(N+H) time and (2^N)H memory, or in something like 2^(N+NH) time and constant memory. Your choice, but that choice is a Morton's Fork for FPGA crackers, even with relatively small hash sizes.
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revised Is there an asymmetric encryption algorithm that maintains the length of the plaintext?
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comment How do spammers verify the validity of a huge amount of email addresses?
While true, a mailer daemon's "undeliverable" message is a common way to clean up a mailing list. That makes it a popular anti-spam feature; some mail programs/providers, when you mark a message in your quarantine as "spam", will send a fake Undeliverable response to the sender, and if the mail-bot cares they'll remove your address from the list.
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revised How to secure usb data storage of Android phones?
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