(or Advanced Encryption Standard), a symmetrical block-cipher algorithm with a 128-bit block size, and key sizes of 128, 192 or 256 bits.
1
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2answers
182 views
Secure Hash Function based on AES
How secure would a hash function be which appends an extra block of 16 zeroed out bytes to the end of the message and then AES-encrypts it with a well-known password (say the first 128 bits of pi) ...
7
votes
4answers
1k views
What is the effect of the different AES key lengths?
How does a changing key length affects the ciphertext, not only in case of AES, but in general? I know that the key spaces become much larger and the number of rounds in case of AES changes, but is ...
2
votes
1answer
1k views
How do I store encrypted files on a web server and decrypt them locally?
I want to store files (images) on a public webserver and let users see them if they know a password. The server shouldn't have the unecrypted files and the server can only serve files, not perform ...
3
votes
1answer
359 views
AES CCM vs CCMP
Are the terms AES CCM and AES CCMP are equivalent, or is there any technical differences between the two?
9
votes
2answers
561 views
Blum Blum Shub vs. AES-CTR or other CSPRNGs
Following on from D.W.'s comments on a previous question, what properties does Blum Blum Shub have that make it better / worse than other PRNGs? Are there significant implementation difficulties or ...
2
votes
1answer
116 views
Aes encryption -The relevance of static matrix in mixcolumns operation
Can someone explain to me the relevance of the static matrix used for the mixcolumns operation in aes encryption.i.e the relevance of why the byte is multiplied by 2 + next byte multiplied by 3 + next ...
1
vote
1answer
365 views
Most effect way to brute force 16 char AES key
I have a file that is encrypted in AES using a 16 char string. The string is (a-zA-Z0-9) and .,?!. It also only contains words from a dictionary (but they can be lower/upper case). What would be the ...
0
votes
1answer
378 views
AES GCM symmetric encryption of data at rest in c#, ciphertext much longer than plaintext
I've written encryption/decryption routines using AES GCM. Code can be found here.
I recently realized that the cipher text is longer than I believe it should be. It should add the tag and IV onto ...
2
votes
1answer
308 views
Is there a standard for OpenSSL-interoperable AES encryption?
Many AES-encrypted things (files, strings, database entries, etc.) start with "Salted__" ("U2FsdGVkX1" in base64).
I hear it's some sort of OpenSSL interoperability thing a b c.
Is there some ...
2
votes
1answer
197 views
Is truncating a hashed private key with SHA-1 safe to use as the symmetric key for AES for data at rest?
I realize this is mixing the purposes between asymmetric and symmetric crypto, but I was wondering if it is safe to use a hashed, truncated private key (asymmetric) as the symmetric key for encrypting ...
0
votes
1answer
86 views
Using “Additional Authenticated Data” as a secondary key
In implementing a cipher in GCM or CCM mode, you are provided the option to add "Additional Authenticated Data" (AAD). This AAD is required for decrypting the cipher text, and seems to be used when ...
4
votes
1answer
533 views
S-box design criteria and random sboxes
What are the disadvantages of using random s-boxes?
In AES, the s-boxes had to obey certain mathematical rules, which? And why?
What security does using hidden s-boxes (GOST) or generating them from ...
1
vote
1answer
401 views
3
votes
1answer
117 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?
1
vote
1answer
332 views
AES GCM implementation in c#
I am implementing an AES cipher in GCM mode in c# and have a few questions. My code is based on the code found here for reference. I'll copy in the relevant portions.
...
2
votes
1answer
144 views
Signing 14 bytes of data
for an embedded device I need to sign a 14-byte string and want to verify that string on the device.
Since there is already an AES-Library on the device, I thought about using the following scheme:
...
0
votes
1answer
784 views
Counter Mode in Advanced Encryption Standard(AES) Algorithm
In Advanced Encryption Standard, If I used "Counter Mode", in it's nonce value, what should I do?
ex. should I divide the nonce value into two? ex. I have 128-bit of nonce, should I divide it from ...
3
votes
3answers
483 views
Which of these 3 AES 128 symmetric encrypt/decrypt routines is most secure?
I am developing a symmetric en-/decryption routine written in c# for a database containing user-specific, sensitive information.
I have narrowed down the implementation to 3 different approaches, ...
2
votes
1answer
295 views
Poor man's SSL - is this method as safe as SSL/TLS?
I need to send data between two applications. I've got requirement that says that data should be transmitted using secure protocol such as SSL/TLS. Data is sent using TCP sockets and I don't have ...
2
votes
2answers
329 views
Capacity of Advanced Encryption Standard in terms of File Encryption
what is the capacity of AES in terms of File Encryption?
is it really good to encrypt a large files in AES? ex. I am encrypting a 8GB of File... is it still good to used AES?
is it still good to used ...
2
votes
1answer
579 views
What is the difference between these AES encryption methods
I am using AES encryption (Rijindael) with Base-64 encoding in Obj-C and VB. I am currently using the following two projects to achieve this:
Obj-C: ...
