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2

Note, there is no legitimate reason to hide the algorithm used if you use a suitably strong passphrase/key. If you are really concerned, you could open the encrypted file in a hex editor and change the fourth byte of the symmetrically encrypted ASCII armored file. E.g., the first four bytes of an symmetric encrypted file are: 8C 0D 04 09 with the ...


2

It looks like the passphrase which was used to encrypt the message with is encrypted with AES256. The algorithm used to encrypt the message is self is not known until the encrypted session key packet is decrypted. This is what pgpdump shows: Old: Symmetric-Key Encrypted Session Key Packet(tag 3)(13 bytes) New version(4) Sym alg - AES with 256-bit key(sym ...


1

The last resort attack in this case is the way some of the early BluRay keys were obtained, that is burning away the outer layers of the chip with HF and reading off the crypto key from the chip itself.


1

Asymmetric Cryptography There are two different parts to creating a TLS session. There is the asymmetric cryptography, portion which is an exchange of public keys between two points. Which is what you saw in your Alice and Bob example. This only allows the exchange of asymmetric keys for asymmetric encryption/decryption. This is the ECDHE portion. The ...


1

You're right that ECDHE is being used for the key exchange and RSA is being used for verifying the server's identity. However, what are you going to do with the exchanged key? You'll need to use a certain algorithm to encrypt/decrypt communication with use of that exchanged key. 128-bits AES is used in this case, in GCM mode. Normally the hashing ...


18

No. This is known as a known-plaintext attack (or a chosen-plaintext attack if you are not only aware of but can select the plaintexts), and is a type of attack that AES is highly resistant to: there are no known attacks of either type that are faster than brute force. If you've got access to the encryption coprocessor (and a good electronics lab), you may ...


4

CTR mode is about encrypting data by generating a key dependent pseudo-random stream and XORing it with the data; so what you describe really is CTR mode, and you don't have to to the XOR yourself. Said otherwise, by encrypting a bunch of zeros and then XORing the result with your actual data, you are just doing a needless extra XOR with zeros. (You are ...


0

If encryption key can be derived using only data persisting in the user database (like user name and password hash for example) that would constitute a major design flaw for the reasons you describe above: original secret (user password) is not needed to derive key and access encrypted data. The way Windows prevents this from happening (or at least the way ...


0

The jsencrypt library implements RSA encryption in javascript which might be what you want but it sounds like you are attempting to create a more basic encryption implementation for educational purposes. I would suggest reading through this library's source and try to pull out pieces that would be relevant to your project.


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The data is protected. The attacker can't decrypt its contents, not even with the (partial) plaintext (otherwise we would be talking of AES as a broken cipher). However, you also need to protect the integrity. For example suppose that the survey contains some Yes/No questions and we were encrypting in CTR mode. If Eve has access to the answers to the ...



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