## Is symmetric encryption deterministic?

@KenY-N No, it’s never deterministic if it is IND-CPA secure, which is a stronger notion than just not encrypting to the same ciphertext when using the same plaintext message. That’s why we have an IV for symmetric ciphers (which mixed with the key give you randomness) and random padding (or ephemeral keys etc.)

## What protocols use symmetric encryption?

Some examples of symmetric encryption algorithms include:

- AES (Advanced Encryption Standard)
- DES (Data Encryption Standard)
- IDEA (International Data Encryption Algorithm)
- Blowfish (Drop-in replacement for DES or IDEA)
- RC4 (Rivest Cipher 4)
- RC5 (Rivest Cipher 5)
- RC6 (Rivest Cipher 6)

**Is AES CBC deterministic?**

AES is a block cipher: it takes as input a block (16 bytes, in the case of AES) and a key (16, 24 or 32 bytes, for AES), and outputs another block (again, 16 bytes). It is a fully deterministic algorithm, fully specified, and everybody in the world ought to obtain the same output block for the same input block and key.

### What is deterministic encryption algorithm?

From Wikipedia, the free encyclopedia. A deterministic encryption scheme (as opposed to a probabilistic encryption scheme) is a cryptosystem which always produces the same ciphertext for a given plaintext and key, even over separate executions of the encryption algorithm.

### Why is RSA deterministic?

Because RSA encryption is a deterministic encryption algorithm (i.e., has no random component) an attacker can successfully launch a chosen plaintext attack against the cryptosystem, by encrypting likely plaintexts under the public key and test if they are equal to the ciphertext.

**What is the difference between deterministic and probabilistic encryption?**

Deterministic encryption creates the same ciphertext, given the same source information and key. Probabilistic encryption introduces a random element, and normally produces unique ciphertext each time it is used.

## What two encryption protocols are commonly used?

TLS/SSL: TLS/SSL is the most common encryption protocol, which is used every day on the Internet. TLS/SSL stands for Transport Layer Security/ Secure Sockets Layer, which is an encryption protocol that ensures communications between a client and server are kept secure.

## Is RSA symmetric or asymmetric?

RSA is named for the MIT scientists (Rivest, Shamir, and Adleman) who first described it in 1977. It is an asymmetric algorithm that uses a publicly known key for encryption, but requires a different key, known only to the intended recipient, for decryption.

**Why RSA is not secure?**

Plain “textbook” RSA is not CPA-secure because it is deterministic: encrypting the same plaintext always yields the same ciphertext. In the IND-CPA security game, the attacker gets to choose two different plaintext messages to be encrypted, receives one of them back encrypted, and needs to guess which one it is.

### Are block ciphers deterministic?

A block cipher is an encryption method that applies a deterministic algorithm along with a symmetric key to encrypt a block of text, rather than encrypting one bit at a time as in stream ciphers. For example, a common block cipher, AES, encrypts 128 bit blocks with a key of predetermined length: 128, 192, or 256 bits.

### What’s the difference between symmetric and asymmetric encryption?

The former is symmetric encryption, while the latter is called asymmetric encryption. First up, we have symmetric cryptography. With this type of key cryptography, the sender and receiver of a message share a single key.

**How did James Ellis come up with the idea of asymmetric encryption?**

James Ellis, a British mathematician, came up with the idea of asymmetric cryptography, i.e., using two separate keys for encryption and decryption. In this scenario, the receiver of the message is actively involved in the process as well, instead of just being a passive passenger.

## Which is the first type of symmetric cryptography?

First up, we have symmetric cryptography. With this type of key cryptography, the sender and receiver of a message share a single key. This key serves as a shared secret between the two parties involved during the cryptography process. There are two kinds of symmetric encryption: