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Backup Encryption 101: Guidelines & Best Practices

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Updated 12th December 2023, Rob Morrison

The definition of an encrypted backup

Encryption by itself is not that difficult of a term – it is a method of data safeguarding, done by reordering or scrambling data so that only authorized parties can return it into its original, normal state. The main purpose of encryption is that the original information in the encrypted data is effectively hidden or inaccessible. In this context, encrypting data backups is one of the easiest safeguards against cyber crimes – but it is not 100% safe, either.

Encryption safeguards data by transforming it from its plain text format (readable text) into ciphertext (an unreadable format) using sophisticated mathematical algorithms and encryption keys. The intention is that data decryption would only be available for users who are supposed to have access to it in the first place.

There are plenty of examples where data encryption has been implemented on a large scale. Some of these examples only utilized encryption only after a massive data breach already happened. Retailer Target had the personal information of over 70 million of its users compromized to a hacker attack back in 2013. It had to pay a massive fee as part of a security breach settlement. Tightening data security (with the addition of encryption) was also a part of this settlement. The Bank of America, on the other hand, implemented a clear encryption framework a while ago because of financial compliance requirements (in this case, PCI DSS compliance, which is discussed later in the article).

The most popular encryption algorithm right now is the AES – Advanced Encryption Standard. It was originally developed to replace DES, or Data Encryption Standard (since it became far too vulnerable as time passed). There are three main key lengths that AES can work with – 256-bit, 192-bit, and 128-bit. AES-256 is widely considered to be the most secure encryption method out there, combining both resistance to cyberattacks and encryption/decryption speed.

Not all encryption is beneficial for regular users – in fact, it can be used for harmful and illegal actions. One of the most common cyber attack types nowadays is ransomware (68.42% of all cyber attacks in 2022), which uses the same encryption techniques to modify unprotected files and demand ransom from their owners in exchange for data decryption.

Additionally, there is a clear line to be drawn between encryption and hashing – since business owners tend to confuse them regularly. Hashing as a process may seem similar to encryption in its nature – because it also describes a process of transforming a piece of data into an illegible combination of symbols. The biggest outlier for hashing when compared with encryption is the fact that hashing is a one-sided process, it is not possible to reverse.

Hashing and encryption also have somewhat different use cases. Encryption is a much wider term that covers a variety of use cases, from data protection to cyber crimes. Hashing, on the other hand, is much more nuanced and mostly used for data integrity checks, password validation, and blockchain.

Encrypted backup benefits

Using encryption on backed up information offers multiple benefits, including:

  • Even if your laptop, hard drive, or smartphone is stolen, lost, or otherwise compromised, encryption prevents the misuse of your information. This guarantees the reliability, accuracy, and validity of your backups, ensuring the data remains unaltered.
  • Encryption safeguards your information, making it unreadable to unauthorized individuals or malicious actors, making sure that both you and your customers have peace of mind knowing sensitive data remains secure and confidential.
  • Encryption restricts access to authorized individuals, ensuring only those intended can decipher and utilize the information.
  • Encryption provides a powerful shield against identity theft and blackmail attempts, as hackers cannot access the information without the decryption key. Additionally, it protects backups from tampering and corruption, further enhancing data security.
  • Encryption helps businesses adhere to regulations and standards like the GDPR or PCI DSS (more on that below). These requirements mandate businesses to encrypt customer personal information when stored or transmitted across public networks.

Types of encryption

With the growing importance of data security, leaving your data backup unencrypted is no longer acceptable within best practices and can likely bring serious issues to any organization. However, navigating all of the different encryption methods available can be challenging. Here are a few examples of factors that may be important to consider during the process of choosing a specific encryption method for your company:

  • Technical skills
  • Security obligations
  • Framework requirements
  • Data types
  • Budget constraints
  • Scalability, and more.

Encrypted backups can be generated using several different methods. For instance, there are two encryption types that are considered commonly usable.

Asymmetric encryption

Asymmetric encryption utilizes a unique approach to data security, employing two mathematically linked keys: a public key and a private key. The public key, readily accessible to anyone, serves the sole purpose of encrypting data. This means any individual can utilize the public key to secure information, ensuring its confidentiality.

Alternatively, only the private key possesses the power to decrypt data (if it was encrypted using the key from the same pair). This controlled access to the decryption key ensures that only authorized individuals can decipher the secured information.

Therefore, the private and public key duo forms the foundation of asymmetric encryption, playing distinct yet crucial roles in securing and safeguarding sensitive data.

Symmetric encryption

Symmetric key algorithms represent a class of cryptographic algorithms that utilize the same key for both decrypting ciphertext (unreadable, encrypted data) and encrypting plaintext (readable data). In simpler terms, they rely on a shared secret key that acts as both the lock and the key, enabling both encryption and decryption of information.

Encryption implementation methods also change quite drastically depending on the state of the data in question. Following a similar idea to the one before, we can present two categories of encryption – at rest and mid transit.

Encryption at Rest

A company’s data is a treasure trove of valuable information. Encryption at rest serves as the sophisticated security system guarding this data, ensuring the confidentiality and integrity of your data even when it’s “at rest,” meaning it resides on a storage medium – hard drive, cloud storage, etc.

Think of how your backups, after their journey through the network, find their final resting place in cloud storage, S3, or your own storage systems. Encryption at rest acts as the vault’s impenetrable shield, encrypting your data with a unique key. This key is the only possible option for accessing that data, granting access to authorized users only and barring entry to anyone who attempts unauthorized decryption.

Even if a hacker gains physical access to the device storing your data, encryption at rest remains their formidable opponent, rendering the data in question useless to anyone without the decryption key.

Encryption at Rest is also what Google Cloud Platform calls its own iteration of SSE – Server-Side Encryption. These two terms are often used interchangeably since SSE is the exact same technology built to protect a customer’s data “at rest” – even though both Microsoft and Amazon have different naming conventions for their iterations of SSE (Server-Side Encryption and Storage Service Encryption, respectively). At the same time, SSE is mostly considered a cloud storage provider feature, and “encryption at rest” can also be applied to data stored outside of cloud storage.

Encryption mid-Transit

Encryption in transit acts as the armored vehicle safeguarding this data, ensuring its confidentiality and integrity while it travels between devices, networks, and the cloud.

The backups are usually being transferred from their origin, whether it is a local or remote machine, server, or cloud-based platform (which could be something like Salesforce, Microsoft 365, Google Workspace or any Cloud service) to their final destination (to any storage including on-premise, remote or Cloud storage systems). During this journey, encryption in transit encloses your data in an impenetrable layer, protecting it from unauthorized access and potential interception.

E2EE, or End-to-End Encryption

End-to-end encryption (E2EE) is a powerful tool for safeguarding your communications in today’s digital world. It acts as an impenetrable shield, encrypting your data on the sending device and ensuring it remains unreadable by anyone except the intended recipient, even if intercepted during transmission.

The sender’s device encrypts the message with a unique key known only to the recipient. This key is used to lock and unlock the message, ensuring its confidentiality throughout its journey.

Third parties like internet service providers, application service providers, hackers, or even the platform itself are denied access to the content of your communication. They can only see the encrypted message, which appears as a jumbled mess without the proper decryption key.

E2EE has gained popularity in various messaging services like Facebook Messenger, WhatsApp, and Zoom. However, its implementation has also sparked controversy. While it enhances user privacy, it can also hinder authorities’ investigations and potentially offer a haven for illicit activities.

Plenty of different cloud storage providers offer end to end encrypted backup capabilities, and even some of the more prominent backup platforms can offer the same feature. It is relatively new to the market so far, but its level of protection is a massive advantage that no enterprise can afford to overlook right now.

Encryption keys and key management services

Encryption keys have been mentioned before in this article, so their exact definition should not be difficult to understand. It is a data piece used in cryptography to perform a decryption operation, an encryption operation, or both. The capabilities of an encryption key depend entirely on the encryption type selected – there would be only one encryption key for a symmetric encryption type, while the asymmetric type always has a key pair (public and private keys).

An encryption key is as strong as it is long – longer keys are more difficult to decrypt, but also require more processing power to perform decryption/encryption operation. Due to their extremely sensitive nature, it is only natural that there would be a dedicated system created specifically for encryption key storage – and there are plenty of such services.

These Key Management Services (such as Google Cloud Key Management, Azure Key Vault, AWS Key Management Service, etc.) offer an easy way to manage and safeguard encryption/decryption keys. It is not uncommon for these key management services to validate encryption keys using the FIPS 140-2 Cryptographic Module Validation Program and employ hardware security modules (HSM) for better key management for its clients.

Key management services can offer a variety of benefits, including:

  • Compliance Assurance: Tamper-evident records facilitate passing compliance audits with ease.
  • Unbreakable Defense: Makes unauthorized data access extremely difficult, requiring intruders to compromise both the key and the data location.
  • Key Rotation: Regularly rotating keys ensure attackers have limited time to exploit any vulnerabilities.
  • Multi-layered Security: Stealing information would require compromising the solution provider, cloud service provider, and the customer, significantly raising the difficulty level.

Legal requirements and frameworks that require encryption

The total number of various legal requirements and/or frameworks that require data encryption in some way is extremely high, which is why we are only going to showcase a small selection of the most commonly known regulations:

  • GDPR, or General Data Protection Regulation.

Article 32(1)(a) emphasizes the importance of using specific measures to safeguard sensitive information. This includes encryption as a potential tool, depending on the nature and scope of processing, the risks involved, and the state of the art. Pseudonymization, another data protection technique, can also be considered.

  • HIPAA, or Health Insurance Portability and Accountability Act.

45 CFR § 164.312(a)(2)(iv) outlines addressable requirements for entities and their associates that fall under the Act’s coverage. It specifies a requirement for electronic protected health information (ePHI) to be encryptable and decryptable using a transparent mechanism. While the requirement itself is open to interpretation, further details can be found in the HIPAA Security Rule technical safeguards.

  • PCI DSS, or Payment Card Industry Data Security Standard.

Requirement 3.4 stipulates that organizations must render Primary Account Numbers (PANs) unreadable wherever they are stored. This includes portable digital media, backup media, and logs. Several methods can be utilized to achieve this, including one-way hashing with strong cryptography, truncation combined with hashing, or the use of index tokens and pads (with secure storage for pads) alongside strong cryptography and robust key management practices.

BYOK encryption type

Bring Your Own Key (BYOK) offers a stringent and highly secure method for safeguarding sensitive information within the cloud environment. This approach deviates from relying on standard cloud provider encryption solutions and empowers users to leverage their own trusted encryption software and keys.

BYOK grants users complete ownership and control over their encryption keys, ensuring data sovereignty and compliance with specific regulations and requirements. Utilizing your own trusted encryption software and keys adds another layer of protection, significantly increasing the difficulty for unauthorized access.

BYOK allows users to choose the encryption software that best integrates with their existing infrastructure, eliminating compatibility challenges and fostering greater flexibility. It also provides users with full visibility into all encryption and decryption activities, enabling comprehensive audits and logging for robust compliance and governance processes.

BYOK is an interesting option for companies that do not wish to rely on cloud services to store their encryption keys, but it is not without its own issues, so it is highly recommended to research the topic before committing to implementing one such system.

Bacula Enterprise and data encryption

Within the competitive landscape of backup and recovery solutions, Bacula Enterprise stands tall as an unparalleled champion of data security. This unrivaled security prowess stems from a multifaceted approach encompassing its architecture, feature set, adaptable deployment options, and extensive customization potential. Further bolstering its security posture is the fact that Bacula’s core components run on the inherently secure Linux operating system.

Security is especially important for Bacula Systems, a core value that is clearly reflected in its product Bacula Enterprise – with its multi-faceted approach to data protection. Bacula transcends the notion of mere “good enough” security. Features like two-factor authentication, role-based access and Time-based One-Time Passwords (TOTP) are not just optional add-ons – they are fundamental building blocks of Bacula’s security architecture, representing just some of the bare minimum basics any organization should expect from a backup solution.

Some other security-oriented features of Bacula Enterprise include integrated antivirus software, several customizable policies for encryption of backup data, granular user control, granular data restriction, MFA support, LDAP access controls, file-level encryption, communication encryption, data poisoning detection, advanced security status reporting, data corruption monitoring, and many others.

Bacula and backup encryption

When it comes to encryption-centric capabilities, Bacula can offer plenty of options to work with, including:

Bacula allows for data to be encrypted and digitally signed before it is sent to its Storage Daemon. These signatures are validated upon restoration, and and and every single mismatch is reported to the administrator. Critically important is that neither the Storage Daemon nor the Director have access to unencrypted file contents during this process.

Bacula Enterprise’s PKI, or Public Key Infrastructure, is composed of x509 public certificates and RSA private keys. It allows for the generation of private keys for every File Daemon – as well as a number of Master Keys that can decipher any of the encrypted backups in the system (these are also generated as a pair – a public key and a private key).

It is heavily recommended that both File Daemon keys and Master keys are stored off-site, as far away from the original storage location as possible. All of the encryption/decryption algorithms mentioned above are also exposed using an OpenSSL-agnostic API that is completely reusable. Its volume format is DER-encoded ASN.1, with the Cryptographic Message Syntax from RFC 3852 being used as a baseline.

Bacula can also store encryption/decryption keys using two different file formats – .CERT and .PEM. The former can only store a single public key with the x509 certificate, it is mostly used for storing a single specific encryption key. The latter is much more complex – it is the default OpenSSL storage format for public keys, private keys, and certificates, and it can store multiple keys at the same time – a great option for asymmetric key generation where there is a key pair to be generated in the first place (public + private).

The future of backup encryption

The future of backup encryption is a dynamic landscape brimming with innovation and driven by the ever-present need to protect valuable data from increasingly sophisticated cyber threats. As encryption itself undergoes constant evolution, the means of safeguarding backups will continue to expand and adapt to meet the growing security challenges of tomorrow.

Here are some of the potential advancements that will shape the future of backup encryption:

  • Artificial intelligence and machine learning will play a vital role in automating and enhancing backup encryption processes. AI-powered algorithms can detect anomalies and potential threats, while machine learning can be used to optimize encryption key management and automate routine tasks.
  • Individuals will increasingly have more control over their data through user-centric encryption solutions. These solutions will empower users to manage their encryption keys, define access permissions, and monitor encryption activities, ensuring greater transparency and accountability.
  • As quantum computers become a reality, traditional encryption algorithms will become vulnerable. Quantum-resistant algorithms, designed to withstand the computational power of quantum computers, may become the new standard for backup encryption (some of the earlier examples of such algorithms are FALCON and CRYSTALS-KYBER).
  • Decentralized complex storage solutions will rise as a more secure and resilient alternative to traditional storage methods. These solutions will distribute data across multiple nodes, making it more difficult for hackers to target and compromise. This also includes the wider adoption of a zero-trust security approach as a whole, using the “least privilege” principle for better security and lower data breach risk.
  • Backup encryption will seamlessly integrate into all data storage and transfer processes, eliminating the need for manual intervention and human error. This will not only enhance security but also streamline data management workflows.

These advancements are capable of granting users greater control and transparency over their information while also having a high chance of safeguarding data against newer threats. By combining user-centric solutions and cutting-edge technology, the future of backup encryption promises a more secure and reliable environment for safe and secure data storage.


Cybercriminals are increasingly targeting backups in an attempt to cripple organizations’ ability to recover from attacks and maximize their control over compromised systems. This underscores the critical importance of backup encryption, not just for business continuity and disaster recovery, but for significantly enhancing your organization’s overall security posture.

Backup encryption acts as a vital security best practice, shielding your organization’s confidential information and thwarting unauthorized access. Backup encryption transforms sensitive information into an unreadable format, creating a relatively strong layer of data protection. This renders the data useless even if attackers intercept it during transmission, as they lack the decryption key necessary to access or decipher it.

The high reliability and key role of encryption in data security makes it a cornerstone of security measures for commercial, military, government and other mission-critical applications. However, correct implementation is necessary to derive a high level of security from encryption – something that Bacula Enterprise can offer. The quality of Bacula’s encryption types and the way it is architected into Bacula’s system – makes it a true leader. It is an exceptionally flexible backup platform with an unusually broad range of different features, including effective data protection methods and extensive encryption support.

About the author
Rob Morrison
Rob Morrison is the marketing director at Bacula Systems. He started his IT marketing career with Silicon Graphics in Switzerland, performing strongly in various marketing management roles for almost 10 years. In the next 10 years Rob also held various marketing management positions in JBoss, Red Hat and Pentaho ensuring market share growth for these well-known companies. He is a graduate of Plymouth University and holds an Honours Digital Media and Communications degree, and completed an Overseas Studies Program.
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