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## Which of the following are asymmetric algorithms? (Select 3 choices.)

- DH
- AES
- 3DES
- ECC
- RC4
- RSA

**Explanation:**

DiffieHellman (DH), Elliptical Curve Cryptography (ECC), and RSA are asymmetric algorithms. DH is an asymmetric key exchange method. DHA and ECC are asymmetric encryption algorithms. Asymmetric encryption, also known as public key encryption, uses a public key to encrypt data and a different, yet mathematically related, private key to decrypt data. Public key infrastructure (PKI) uses a certificate authority (CA) to tie a public key to a user ID to further ensure the confidentiality of data. Asymmetric encryption algorithms use more complex mathematical functions than symmetric encryption algorithms. As a result, asymmetric encryption algorithms take longer to encrypt and decrypt data than symmetric encryption algorithms. Other examples of asymmetric encryption algorithms include Digital Signature Algorithm (DSA) and ElGamal.

Advanced Encryption Standard (AES), RC4, and Triple Data Encryption Standard (3DES) are examples of symmetric encryption algorithms. When symmetric encryption algorithms are used, the same encryption key is used to encrypt and decrypt data. Two types of symmetric algorithms exist: block ciphers and stream ciphers. Block ciphers derive their name from the fact that they encrypt blocks of data. For example, AES encrypts 128bit blocks of data. By contrast, stream ciphers are typically faster than block ciphers because stream ciphers encrypt text of variable length depending on the size of the frame to be encrypted? stream ciphers are not limited to specific block sizes. For example, RC4, a stream cipher, can encrypt data in streams of 8 through 2,048 bits. Other examples of symmetric encryption algorithms include International Data Encryption Algorithm (IDEA), Skipjack, and Blowfish.

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