Data ecryption in transit and at rest: What to use and when

Data encryption is one of the most effective tools for protecting sensitive information belonging to users and organizations. However, questions often arise about the different types of encryption and when each should be applied. In this article, we explain what data encryption in transit and at rest is, their differences and advantages, and when it makes sense to use each one.

What is data encryption?

Data encryption is a process that transforms information into an unreadable format for unauthorized individuals or systems. To read or use the data, it must be decrypted using the corresponding key.

Encryption can be applied at different stages of the data lifecycle: while it is stored (at rest) or while it is being transferred from one place to another (in transit).

What is data encryption in transit?

Data encryption in transit protects information as it moves between two points. This includes data transmission between users and servers, between applications, or between devices connected to a network.

Examples of Data in Transit:

• Information submitted through web forms
  
  
• Files transferred between servers
  
  
• Emails
  
  
• Mobile app or API communications
  
  

Common Technologies for In-Transit Encryption:

• TLS (Transport Layer Security): Used to encrypt web connections (HTTPS)
  
  
• IPSec: A protocol used in virtual private networks (VPNs)
  
  
• SSH (Secure Shell): For secure remote connections
  
  

What is data encryption at rest?

Data encryption at rest is applied to information stored on physical or virtual devices. Its purpose is to protect data from unauthorized access, even if an attacker gains access to the physical or logical storage.

Examples of Data at Rest:

• Files stored on hard drives, SSDs, or mobile devices
  
  
• Databases, whether local or cloud-based
  
  
• Backups
  
  
• Data stored on external storage systems
  
  

Common Technologies for At-Rest Encryption:

• AES (Advanced Encryption Standard): One of the most widely used standards due to its high security and performance
  
  
• BitLocker (Windows) and FileVault (macOS): Full-disk encryption solutions
  
  
• Database and cloud storage encryption
  
  

Differences between in-transit and at-rest encryption

Although both types of encryption aim to protect data, they apply at different stages and in different contexts:

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Advantages of data encryption in transit

• Protects communications from eavesdropping and interception
  
  
• Ensures data integrity during transmission
  
  
• Essential for secure web and mobile app usage
  
  

Advantages of data encryption at rest

• Safeguards data in case of theft of devices or storage media
  
  
• Helps meet privacy and data protection regulations like GDPR, HIPAA, or PCI DSS
  
  
• Prevents third-party access to data on compromised systems
  
  

When to use encryption in transit and at rest

Encryption in transit is essential whenever sensitive data is transmitted over networks that are not entirely secure, such as the Internet. This includes HTTPS communications on websites, sending emails, or connecting to cloud services.

On the other hand, encryption at rest is critical when handling confidential data that remains stored for any period of time. It is particularly important in environments where there is a risk of device theft or unauthorized access to storage systems.
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Do you have to choose one over the other?

The answer is no. The best practice is to implement both types of encryption in a complementary manner. Encryption in transit and at rest function as layered security controls that protect data throughout its entire lifecycle—from the moment it's generated or received, through transmission and storage.
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Data encryption implementation process

1. Assessment and planning

Before deploying any technology, it’s crucial to understand:

• What data to protect: Identify sensitive information such as personal data, financial records, or trade secrets
  
  
• Where it resides and how it moves: Map where data is stored and how it is transmitted
  
  
• Which regulations apply: Understand legal requirements and industry standards
  
  

A thorough initial analysis ensures encryption is effective and aligned with your security goals.
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2. Encryption strategy design

Encryption must address two fronts:

Data in Transit
Protects data as it travels over public or private networks. Key considerations include:

• Use secure protocols like TLS 1.2 or 1.3, SSH, VPN, or IPSec
  
  
• Configure valid digital certificates and disable outdated protocols
  
  

Data at Rest
Secures stored data (on disks, in databases, in backups). This involves:

• Implementing disk encryption (e.g., BitLocker, LUKS, AWS EBS Encryption)
  
  
• Using database-level encryption (e.g., Transparent Data Encryption – TDE)
  
  
• Ensuring backups and removable media are encrypted
  
  

3. Technical implementation

Now it’s time to get hands-on:

• Configure HTTPS on your web apps and enforce its use
  
  
• Ensure databases and file systems use robust algorithms (AES-256 for at-rest data, RSA-2048 or higher for public keys)
  
  
• Audit all integration points and apply encryption accordingly
  
  

4. Secure key management

Encryption is only as strong as your key management practices:

• Use a secure key manager (e.g., HSM or cloud services like AWS KMS or Azure Key Vault)
  
  
• Set policies for regular key rotation
  
  
• Limit and audit access to encryption keys
  
  

5. Testing and validation

Before considering the project complete:

• Conduct functional and performance testing
  
  
• Verify encryption is correctly implemented at all identified points
  
  
• Run vulnerability scans and security audits
  
  

6. Monitoring and maintenance

Security is an ongoing process:

• Monitor certificates, keys, and encrypted systems
  
  
• Update protocols and algorithms in response to emerging threats
  
  
• Document processes and train staff accordingly
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Encrypting data in transit and at rest is essential to safeguard information from a wide range of threats. Implementing both strategies not only enhances overall system security but also ensures compliance with increasingly strict data protection regulations.

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