Topic 7a—Encryption Fundamentals
Encryption is the process of converting a plaintext message into a secure-coded form of text, called ciphertext.
The ciphertext cannot be understood without converting back, via decryption—the reverse process—to plaintext.
This is done via a mathematical function and a special encryption/decryption password called the key. In many
countries, encryption is subject to governmental laws and regulations that limit the key size or define what may not
be encrypted.
Encryption is part of a broader science of secret languages called cryptography, which is generally used to:
• Protect information stored on computers from unauthorized viewing and manipulation
• Protect data in transit over networks from unauthorized interception and manipulation
• Deter and detect accidental or intentional alterations of data
• Verify authenticity of a transaction or document
Encryption is limited in that it cannot prevent the loss of data. It is possible to compromise encryption programs
if encryption keys are not protected adequately. Therefore, encryption should be regarded as an essential, but
incomplete, form of access control that should be incorporated into an organization’s overall computer security
program.