How Does Encryption Work?

by Josienita Borlongan

Encryption and Decryption

Data normally comes in plaintext or cleartext form. In order to disguise or hide the message from an unintended recipient, some choose to encrypt the data. When one encrypts a message, it becomes unreadable. The encryption converts the plaintext to "cipher text," thereby securing the integrity of the data. The way the process works is that the sender will provide a passphrase to the recipient in a separate email or by secured phone call. When the recipient receives the encrypted message, using the passphrase will decrypt the message back to its original cleartext or plaintext format.


In order to encrypt and decrypt data, one should use a process called cryptography. It is a method using mathematics to store sensitive information. One can transmit the encrypted sensitive information via an unsecured network without fear of compromising the content. A mathematical function called a "cryptographic algorithm" or a cipher, works in combination with a key, whether that is a word, number or phrase to encrypt a message in plaintext. The plaintext becomes a ciphertext using different keys. It is important to use a strong cryptographic algorithm and keep the key or passphrase in secrecy.


A key is necessary for encrypting messages into ciphertexts. It has a value that works with cryptographic algorithm. Bits measure the size of a key; the bigger the key, the more secure the ciphertext is. In conventional cryptography, the 80-bit key is similar in strength as that of a 1,024-bit key used in public cryptography. It is important when picking keys that they are large enough to be secured but small enough for quick application. Larger keys stay secure longer than smaller ones. Therefore, it is good to keep this in mind when trying to encrypt a message that would last for many years. The keys used are stored in encrypted form. In the case of PGP (Pretty Good Privacy) keys, they are stored in the hard drive as files, called keyrings, either as public or private keys. The public keys sent to recipients should be stored in the public keyring, while the private keys that the sender uses should be stored in the private keyring. Losing a private keyring poses a problem in decrypting messages encrypted to keys using that keyring.

Types of Encryption

There are several ways to use encryption. Web browser and email encryptions are the most common ones. Web browsers automatically encrypt data by using a secure or proxy server. The encrypted site has the identifiable address beginning with https, with the s standing for secure. This server then decrypts the data upon arrival. For emails, use of PGP is the common encryption of choice. This encrypts messages, personal files and folders. Hard drive encryption is also a common type of encryption. This keeps the stored sensitive data secure. Complete encryption of the hard drive, restrict user operator encryptions and creating a dedicated encrypted virtual drive that contains only encrypted data are the three methods for hard drive encryption.

About the Author

Josienita Borlongan is a full-time lead web systems engineer and a writer. She writes for, and various other websites. She is a Microsoft-certified systems engineer and a Cisco-certified network associate. She graduated with a Bachelor of Science in medical technology from Saint Louis University, Philippines.