Which of the following methods of encryption uses a single key to encrypt and decrypt data?
A.
Asymmetric
B.
Symmetric
C.
S/MIME
D.
PGP
Explanation:
Symmetric encryption is a type of encryption that uses a single key to encrypt and
decrypt data. Symmetric encryption algorithms are faster
than public key encryption. Therefore, it is commonly used when a message sender needs to encrypt
a large amount of data. Data Encryption
Standard (DES) uses symmetric encryption key algorithm to encrypt data.
Answer option A is incorrect. Asymmetric encryption is a type of encryption that uses two keys – a
public key and a private key pair for data
encryption. The public key is available to everyone, while the private or secret key is available only to
the recipient of the message. For
example, when a user sends a message or data to another user, the sender uses a public key to
encrypt the data. The receiver uses his
private key to decrypt the data.
Answer options C and D are incorrect. Secure Multipart Internet Mail Extensions (S/MIME) and
Pretty Good Privacy (PGP) are types of
asymmetric encryption. Both are based on public key cryptography where each user has two keys, a
public key for encrypting and a private
key for decrypting messages.