Linked Questions

59
votes
6answers
9k views

Soft question: Examples where lack of mathematical rigour cause security breaches?

Cryptographic tools can often become adopted even when their security proofs lack mathematical rigour - or altogether missing. Are there famous cases of security breaches in the industry, where the ...
1
vote
2answers
2k views

Understanding how padding works when using Block Cipher

I'm trying to understand how padding works when using block ciphers. Padding may be required when the size of the plain text is not a multiple of the block size If that's so, then I don't ...
5
votes
2answers
908 views

Can AES-CBC be safely used in combination with RSA, or must it be CBC-MAC?

The plan is to encrypt files using an AES-256 in CBC mode secret key. The secret key itself will be encrypted with a RSA 2048-bit public key. Is using AES-CBC sufficiently secure if used in ...
4
votes
2answers
132 views

Is there a maximum amount of data which can be encrypted using a symmetric (AES256) key?

I am working on an application where we will be encrypting billions of small (< 2,000 bytes) records. Combined, we are facing many TB of data. Each record will be encrypted independently, using a ...
1
vote
1answer
216 views

AES-GCM cipher - Nonce vs IV

I am using a Python library called PyCryptodome, which offers the following API for AES-GCM ciphers: https://pycryptodome.readthedocs.io/en/latest/src/cipher/aes.html As you see, IV is not ...
1
vote
4answers
76 views

Can I increase strength of ECB by decorrelating input data with compression

I know that ECB block cipher mode is the weakest method of encryption because repetitions in input data with a stride of a block size lead to repetitions in output data. However, as I may consider, ...
0
votes
1answer
66 views

Signal Protocol Header key encryption initialization vector

In Signal Protocol when you use a Double Ratchet you have 2 options: Normal encryption = header + ciphertext Encrypted header encryption = ...
1
vote
1answer
84 views

Are there any security drawbacks for simply encrypting and MACing my JWS token (JWT)?

This question, while related, doesn't answer the security aspect I have in mind. I understand that signatures make it impossible for the tokens to be modified. But if I want the JWS token content to ...
0
votes
2answers
115 views

IVs in WEP encryption

First, I'm pretty new to the world of encryption. As I understand it, in WEP, the plaintext and CRC are XOR'd with the IV and the key (or more accurately, the key/stream, which is produced by a pseudo-...
1
vote
1answer
97 views

Why does a padding block exist for ECB and CBC modes?

In ECB and CBC mode, the size of cipher text is more than the plain-text size by one padding block. From what I read, ECB does a simple encryption to each 64 bit block of a Plain text, and produces ...
3
votes
0answers
114 views

How to break GCM that uses the same IV

I have an implementation that natively uses the same IV (12 bytes of 0) for all encryption. The key is always a 32 byte SHA-512 hash. I know via this post that I ...