What Is Encryption?

Encryption converts readable data into unreadable code that can only be decoded with the correct key. Think of it as putting your data in a lockbox — anyone can see the box, but only those with the key can access what is inside.

For businesses, encryption is a fundamental security control that protects sensitive information from theft and exposure.

How Encryption Works

The Basic Concept

Encryption uses mathematical algorithms:

1. Original data (plaintext) is processed with an encryption algorithm 2. A key determines the specific transformation 3. Result is encrypted data (ciphertext) 4. Decryption reverses the process using the key

Without the correct key, encrypted data is effectively random characters.

Symmetric Encryption

One key for both encryption and decryption:

How it worksSame key encrypts and decrypts.

AnalogyA padlock where the same key locks and unlocks.

Use casesStoring encrypted data, fast encryption of large amounts.

ChallengeKey must be shared securely between parties.

Asymmetric Encryption

Two related keys — public and private:

How it worksPublic key encrypts; only matching private key decrypts.

AnalogyA mailbox anyone can put mail into, but only you can open.

Use casesSecure communication, digital signatures, key exchange.

BenefitPublic key can be shared openly.

Common Algorithms

Standard encryption methods:

AES (Advanced Encryption Standard)Current standard for symmetric encryption. Used widely.

RSACommon asymmetric algorithm for key exchange and signatures.

TLS/SSLProtocol using both symmetric and asymmetric encryption for secure communication.

Where Encryption Applies

Data at Rest

Data stored on devices and systems:

Full disk encryptionEntire storage device encrypted. Protects if device is lost or stolen.

File encryptionIndividual files or folders encrypted. Protects specific sensitive content.

Database encryptionData in databases encrypted. Protects stored business data.

Backup encryptionBackup copies encrypted. Protects off-site data.

Data in Transit

Data moving across networks:

Website encryption (HTTPS)Web traffic encrypted between browser and server.

Email encryptionMessage content protected during transmission.

VPN encryptionNetwork traffic encrypted through tunnel.

File transfer encryptionFiles encrypted during transmission.

Application Encryption

Encryption within applications:

Password hashingStored passwords protected (technically one-way encryption).

TokenisationSensitive data replaced with tokens.

End-to-end encryptionData encrypted from sender to recipient, inaccessible even to provider.

Business Applications

Device Encryption

Protecting laptops, phones, and tablets:

Windows BitLockerBuilt into Windows Pro and Enterprise. Encrypts entire drives.

macOS FileVaultBuilt into macOS. Full disk encryption for Macs.

Mobile device encryptioniOS and Android encrypt devices by default.

Why it mattersLost or stolen devices cannot be accessed without credentials.

Email Encryption

Protecting email content:

Transport encryption (TLS)Most email servers encrypt during transmission.

End-to-end encryptionContent encrypted so only sender and recipient can read.

When to useSensitive information, compliance requirements, client confidentiality.

Cloud Storage Encryption

Protecting cloud-stored data:

At-rest encryptionMajor cloud providers encrypt stored data.

In-transit encryptionData encrypted during upload and download.

Client-side encryptionData encrypted before leaving your devices.

Key managementWho controls encryption keys matters.

Website Encryption

Protecting web visitors:

HTTPSAll websites should use HTTPS, not HTTP.

SSL/TLS certificatesEnable HTTPS on your website.

Why it mattersProtects visitor data, builds trust, affects search rankings.

Key Management

The Critical Challenge

Encryption is only as strong as key management:

Lost keys mean inaccessible data
Stolen keys mean exposed data
Poor key practices undermine encryption

Best Practices

Managing encryption keys properly:

Secure storageKeys stored securely, not in obvious locations.

Access controlOnly authorised personnel can access keys.

BackupRecovery options if primary key access is lost.

RotationPeriodic key changes to limit exposure duration.

SeparationKeys stored separately from encrypted data.

Recovery Planning

Preparing for key loss:

Document key recovery procedures
Maintain secure key backups
Test recovery processes
Consider escrow for critical keys

Implementation Considerations

Performance Impact

Encryption uses computing resources:

Modern hardware handles encryption efficiently
Performance impact is usually minimal
Some operations may be slower with older hardware
Proper implementation minimises impact

Compatibility

Ensuring encryption works:

Encrypted data requires compatible decryption
Key management across devices and users
Legacy system compatibility
Backup and recovery with encryption

Compliance Requirements

Regulatory considerations:

Privacy regulationsMany require encryption for personal data.

Industry standardsHealthcare, finance, and other sectors mandate encryption.

Contract requirementsClients may require encryption protections.

Breach notificationEncryption may affect notification requirements after breaches.

Common Mistakes

Relying on Encryption Alone

Encryption is not a complete security solution:

Does not protect against authorised users misusing data
Does not prevent attacks on running systems
Does not replace access controls
Part of defence in depth, not single solution

Poor Key Management

Keys undermine encryption:

Storing keys with encrypted data
Using weak or guessable keys
Sharing keys insecurely
Not rotating keys appropriately

Inconsistent Implementation

Gaps in encryption:

Encrypting some devices but not others
Protecting data in transit but not at rest
Encryption for some applications but not all
Backup copies unencrypted

Ignoring Usability

Encryption that blocks work:

Complex processes users bypass
Recovery procedures too difficult
Performance impact causing workarounds
Implementation that creates friction

Getting Started

Minimum Encryption Measures

For most small businesses:

1. Enable device encryption on all computers and mobile devices 2. Use HTTPS on your website 3. Ensure cloud services encrypt data 4. Encrypt backup copies 5. Use encrypted email when appropriate

Improving Your Posture

As you mature:

Formal key management procedures
End-to-end encryption for sensitive communications
Client-side encryption for sensitive cloud data
Regular review of encryption practices
Encryption included in security policies

Working with IT Providers

Getting help:

Assess current encryption status
Implement appropriate encryption
Manage keys securely
Monitor and maintain encryption
Include encryption in security reviews

Encryption is a fundamental security control. Properly implemented, it provides strong protection for your business data against theft and exposure.