Tagged Questions
3
votes
1answer
110 views
Combining AEAD with RSA
'Hybrid' encryption, where we combine symmetric encryption with public-key cryptography, is pretty 'tried and tested'.
To summarise, we generate a symmetric key and encrypt it using RSA. We would ...
3
votes
1answer
323 views
AES CCM vs CCMP
Are the terms AES CCM and AES CCMP are equivalent, or is there any technical differences between the two?
3
votes
1answer
111 views
How to communicate authentication tag for GCM?
I have written some code to do AES in GCM. I currently manually append the tag property to the ciphertext, is this the proper way to communicate the authentication tag?
3
votes
1answer
160 views
Using a derived key for CMAC
Consider the following authenticate-and-encrypt scheme that uses AES-128 in CBC mode for encryption and AES-128 - based CMAC for authentication:
Two keys are derived from the master key k (16 byte): ...
3
votes
2answers
138 views
Is this streamable combination of encryption and MAC secure?
I want to combine encryption and MAC.
For encryption I use AES-256 with CBC and PKCS5Padding.
For MAC I use HmacSHA512.
I use the Encrypt-then-Mac approach (calculate MAC over the ciphertext and ...
3
votes
1answer
124 views
Safely use CryptSignAndEncryptMessage?
I am developing an application that sends messages which I want to encrypt and sign. The CryptoApi offers a function called CryptSignAndEncryptMessage.
The description says, what this function ...
5
votes
2answers
848 views
Why do we need special key-wrap algorithms?
Wikipedia says:
Key Wrap constructions are a class of symmetric encryption algorithms designed to
encapsulate (encrypt) cryptographic key material.
We are using these algorithms to encrypt ...
4
votes
1answer
580 views
How can I encrypt + authenticate short strings into similar short ciphertexts?
I wish to manipulate short ASCII strings (namely unpredictable domain names) into a form which cryptographically assures authenticity and confidentiality, for use in the local part of email addresses. ...
1
vote
1answer
160 views
ID-Secret Scheme
I have an ID-Secret scheme and I'd like to hear if there are any vulnerabilities present.
Party 1 and Party 2 hold some credentials, an ID and a Secret.
Party 1 Creates this message:
...
53
votes
5answers
6k views
Should we MAC-then-encrypt or encrypt-then-MAC?
Most of the time, when some data must be encrypted, it must also be protected with a MAC, because encryption protects only against passive attackers. There are some nifty encryption modes which ...
