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### AES_256_ENCRYPT_CTR(key, sha-1(plainText)+plainText) VS AES-GCM, which is more secure? [duplicate]

What if we encrypt sha-1 hash of the plain text, along with the plain text using AES-256 in CTR mode? How much future proof the above method would be in comparison to AES-GCM or any other method ...
219 views

### Why not just encrypt the message and the hash of the message to achieve cryptographic integrity? [duplicate]

I've always seen MACs as a way to provide integrity and authentication. You would just append it to some message in clear. But this is clearly not the case when you're doing Encrypt Then Mac. When ...
1k views

### Does CBC encryption of a hash provide authenticity?

Given a message $M$ and a cryptographic hash function $H$, let $f(M) = E_K(M || H(M))$ where $E_K$ is AES-128-CBC encryption with PKCS#5 padding. Take $H = \textrm{SHA-256}$ if it matters. In other ...
1k views

### HMAC versus encrypted hash

When encrypting a message with a symmetric key, it seems like the best practice is to first encrypt the message, then run the cipher text and key through HMAC, appending the result to the cipher text. ...
2k views

### Is there a generic attack on encrypted CRC32 when used as a MAC?

I am examining a protocol that uses CRC32 as a MAC (see note 1) the weaknesses of this method but I would nevertheless like to see if it is just weak or actually relatively easily to break. The ...
1k views

### Establish a secure connection between a Bluetooth Low Energy device and an Android App using ECDH

Im very new to security and trying to learn how to establish a secure connection between a android application and a Bluetooth Low Energy device with limited hardware performance. The procedure: App:...
559 views

### Using checksum instead of hash for authenticating ciphers

Lets assume for a specific situation we cannot use authenticated encryption like GCM ... If we were to use CTR, what would you think of using a checksum on plain text then encrypt whole. The reason ...
1k views

### Is appending the hash of the plaintext to the end of an encrypted message sufficient to ensure integrity?

Is appending the hash of the plaintext to the end of an encrypted message sufficient to ensure integrity? My reasoning is that the attacker doesn't know all the plaintext, so by having a hash, the ...
284 views

### Least-weak way to authenticate using only AES ECB/CBC

I have an embedded application that needs to occasionally get secure updates from a server. The only crypto library I have available for the chip is an AES-256 cipher (ECB and CBC, encrypt/decrypt). ...
529 views

### Why do different applications of hash functions demand different properties of the hash function?

A strong cryptographic hash function in general must guarantee several properties, including: Preimage resistance, second preimage resistance and collision resistance. It turns out, however, that ...
1k views

### How to make cookies tamper-proof and secure by using encryption and hash / MAC

Our company has decided to ditch server side sessions in favor of storing authenticated information such as user id and access privilege information in a cookie. Before everyone jumps up and down ...
416 views

### Hash-Then-Encrypt or Encrypt-the-Hash?

My question is would it make any difference if I use SHA3 and hash a block of data and then encrypt it using RSA is most secure to do the reverse? The question is about Site-To-Site transmission ...
1k views

### Parallel file encryption and authentication for large files

For a cloud storage upload client I want to encrypt files during upload, so that they cannot be read by the cloud service provider or anyone who gains access to the account. I would like to use some ...
701 views

### Hash length vs Data length

I'm very (!) new to the world of cryptography, so pardon me if this question is very basic. Related to hashing, something that hasn't become clear to me is the relation between data length and hash ...
512 views

### How to use AES-CBC to password-encrypt a small block of stored data

I have a small block of data (16 bytes) that I am required to encrypt, store (in an unsecure, visible location). Later I have to retrieve and decrypt it. I must use AES-CBC and a user-entered ...

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