Encryption algorithms are mathematical procedures used to secure data by converting it into a format that is unreadable to unauthorized users. These algorithms use keys, which are secret codes, to transform plain text into cipher text. Only those with the correct key can decrypt the data back into its original form, ensuring confidentiality and protection against unauthorized access. There are various types of encryption algorithms, including symmetric encryption, where the same key is used for both encryption and decryption, and asymmetric encryption, which uses a pair of keys: a public key for encryption and a private key for decryption. These algorithms are essential for securing communications, such as in online banking and email services.