The definition of encryption is the process of transforming readable information into an unreadable format so that it can only be accessed by someone who has the correct key or authorization to decrypt it. Encryption is one of the fundamental technologies behind modern digital security and is used to protect everything from personal messages and passwords to business files, payment information, government communications, and stored data.
Whenever information is transmitted across a network or stored on a computer, smartphone, server, USB drive, or cloud platform, there is a possibility that an unauthorized person could gain access to it. Encryption reduces that risk by making the information unintelligible without the appropriate cryptographic key.
However, encryption is a broader subject than simply “scrambling” data. There are different encryption methods, algorithms, key structures, security levels, and practical applications.
In this guide, we go through the definition of encryption, explain how encryption works, compare symmetric and asymmetric encryption, look at encryption for stored and transmitted data, and explain concepts such as encryption keys, AES, RSA, end-to-end encryption, hashing, and encrypted storage.
What Is the Definition of Encryption?
Encryption explained in simple terms
Encryption converts information known as plaintext into an unreadable form known as ciphertext.
For example, imagine a document containing:
Before encryption, anyone who gains access to the document could potentially read the information.
After encryption, the information may appear as an unintelligible sequence of characters and data. To convert that ciphertext back into readable information, the correct decryption process and cryptographic key are required.
The basic process therefore looks like this:
Encryption does not necessarily prevent someone from stealing or copying data. Instead, its primary purpose is to make the stolen information unusable to anyone who does not possess the required key.
Why is encryption important?
Modern organisations generate and store enormous quantities of sensitive information.
This can include:
Customer information
Financial records
Login credentials
Intellectual property
Business documents
Internal communications
Medical records
Government information
Security data
Personal photographs and files
Without adequate protection, anyone who gains access to a device or network could potentially read this information.
Encryption provides an additional security layer by protecting the content itself.
How Does Encryption Work?
Plaintext and ciphertext
Two fundamental terms in cryptography are plaintext and ciphertext.
Plaintext is the original readable information.
Ciphertext is the encrypted version.
An encryption algorithm performs mathematical operations on the plaintext together with an encryption key. The resulting ciphertext should be extremely difficult to convert back into plaintext without the appropriate key.
Good modern encryption is designed so that simply knowing which algorithm was used should not be enough to recover the information.
The security instead depends heavily on the cryptographic key.
What is an encryption key?
An encryption key is a value used by a cryptographic algorithm when encrypting or decrypting information.
You can think of the key as the secret component that determines how information is transformed.
Modern encryption keys are usually long sequences of bits rather than traditional passwords.
For example, encryption systems may use keys that are:
128 bits
192 bits
256 bits
2048 bits
4096 bits
The appropriate key length depends on the encryption technology being used.
Generally, a larger key space makes brute-force guessing more difficult, although key length alone does not determine whether an encryption system is secure.
The strength of the algorithm, implementation, key generation and key management are also extremely important.
The Two Main Types of Encryption
Encryption is commonly divided into two major categories:
Symmetric encryption
Asymmetric encryption
Both protect information, but they operate differently.
What Is Symmetric Encryption?
One key for encryption and decryption
Symmetric encryption uses the same secret key, or closely related secret information, to encrypt and decrypt the data.
The process can be simplified as:
Data + Secret Key → Encrypted Data
The recipient then uses the same secret key to decrypt the information.
Symmetric encryption is generally very fast, making it particularly useful when large amounts of data need to be encrypted.
It is commonly used for:
Hard drives
SSDs
USB storage
Databases
File encryption
Backup systems
VPN traffic
Large volumes of network data
What is AES encryption?
One of the best-known symmetric encryption algorithms is AES, which stands for Advanced Encryption Standard.
AES supports key sizes including:
AES-128
AES-192
AES-256
The numbers refer to the key length.
AES-256 is widely associated with high-security applications because of its large key space and strong cryptographic design when correctly implemented.
AES can be used to protect stored files, encrypted drives, communication systems and many other types of digital information.
What Is Asymmetric Encryption?
Public and private keys
Asymmetric encryption uses two related cryptographic keys rather than one shared secret key.
These are known as:
Public key
Private key
The public key can be distributed to other people.
The private key should remain secret.
In a simplified encryption scenario, information encrypted with someone’s public key can only be decrypted using the corresponding private key.
This creates an important advantage.
Two people do not necessarily need to exchange the same secret key before communicating securely.
Where is asymmetric cryptography used?
Public-key cryptography is used extensively in modern digital infrastructure.
Applications include:
Secure websites
Digital certificates
Secure communications
Authentication
Digital signatures
Secure key exchange
Email encryption
Algorithms associated with public-key cryptography include RSA and cryptographic systems based on elliptic curves.
Symmetric vs Asymmetric Encryption
Both encryption methods have advantages.
Symmetric encryption is typically faster and better suited to encrypting large amounts of information.
Asymmetric cryptography solves important problems involving identity, authentication and secure key exchange.
In practice, modern security systems frequently combine both technologies.
For example, a secure connection may initially use asymmetric cryptographic techniques to establish trust and exchange secret information. The actual flow of data can then be protected using faster symmetric encryption.
This combination provides both security and performance.
What Is Encryption at Rest?
Protecting stored information
Encryption at rest refers to encrypting information while it is stored.
This can include data stored on:
Computers
Servers
Hard drives
SSDs
Smartphones
Tablets
USB drives
Backup devices
Databases
Cloud storage systems
The objective is to prevent someone from simply accessing the storage device and reading its contents.
For example, if an unencrypted laptop is stolen, someone may attempt to remove the drive and access the files from another computer.
If the drive is properly encrypted, accessing the physical storage device does not automatically provide access to the information stored on it.
What Is Full-Disk Encryption?
Full-disk encryption protects most or all of the information stored on a drive.
Instead of individually encrypting selected documents, the entire storage system is protected.
When the authorised user unlocks the device, information can be decrypted as required.
Without the appropriate authentication or cryptographic key, the stored information should remain unreadable.
Full-disk encryption is particularly valuable for:
Business laptops
Mobile devices
Sensitive workstations
Portable computers
Government devices
Devices containing confidential information
However, full-disk encryption does not solve every security problem.
If an attacker gains access while the computer is already unlocked, encryption may not prevent them from accessing information through the active operating system.
What Is Encrypted Storage?
Encrypted storage refers to storage devices or systems designed to protect stored information using encryption.
This can include:
Encrypted USB drives
Encrypted external hard drives
Secure SSDs
Encrypted network storage
Hardware-encrypted storage devices
Some products rely primarily on software encryption, while others incorporate dedicated security hardware.
Hardware-based encrypted storage may include features such as:
PIN authentication
Cryptographic processors
Automatic locking
Tamper-resistant hardware
Secure key storage
Protection against repeated login attempts
Encrypted storage can be particularly useful when sensitive data needs to be transported physically.
What Is Encryption in Transit?
Encryption in transit protects information while it moves between systems.
Examples include data travelling between:
A browser and website
A smartphone and server
Two company offices
A user and cloud application
Computers connected through a VPN
Without encryption, someone monitoring the network may potentially be able to intercept information.
Encryption makes intercepted traffic significantly more difficult to interpret.
What Is TLS Encryption?
TLS stands for Transport Layer Security.
It is one of the technologies used to secure communications across the internet.
When you visit a website using HTTPS, TLS is typically used to establish a secure connection between your browser and the website’s server.
TLS can provide several important protections, including:
Encryption of transmitted information
Authentication
Protection against modification of data during transmission
This is why HTTPS is particularly important for websites handling passwords, personal information or payment details.
What Is End-to-End Encryption?
End-to-end encryption, often abbreviated E2EE, is designed so that information is encrypted on the sender’s device and only decrypted by the intended recipient.
Ideally, intermediaries transporting the communication cannot read the content.
This is commonly associated with secure messaging services.
Imagine Alice sends Bob a message.
With properly implemented end-to-end encryption:
Alice’s device encrypts the message.
The encrypted message travels through the communication infrastructure.
Bob’s device receives it.
Bob’s device decrypts the message.
A server responsible for delivering the message should not possess the key required to read the protected content.
This differs from systems where data is encrypted between the user and a company’s server but decrypted by the service provider before being encrypted again for delivery.
Encryption vs Hashing
Is hashing the same as encryption?
No.
Hashing and encryption are related to information security but serve different purposes.
Encryption is designed to be reversible.
Encrypted information can be converted back into plaintext when the correct key is available.
Hashing is normally designed to work in one direction.
A hash function takes information and produces a fixed-size output known as a hash or digest.
Hashing is commonly used for:
Password verification
Integrity checking
Digital signatures
File verification
A properly designed cryptographic hash should not provide a straightforward method for recovering the original input from the hash.
Therefore:
Encryption protects confidentiality.
Hashing is commonly used for verification and integrity-related purposes.
The two concepts should not be treated as interchangeable.
Encryption vs Encoding
Encoding is also frequently confused with encryption.
Encoding changes information from one representation into another, usually so that a system can store or transmit it correctly.
For example, Base64 is an encoding method.
Encoding does not provide meaningful cryptographic confidentiality because anyone who knows the encoding format can reverse it.
Encryption, on the other hand, relies on cryptographic algorithms and keys.
This is an important distinction when assessing whether data is actually protected.
What Is a Cryptographic Algorithm?
A cryptographic algorithm defines the mathematical process used to encrypt or decrypt information.
Modern cryptographic algorithms are carefully designed and extensively analysed.
Examples commonly associated with encryption and public-key cryptography include:
AES
RSA
ChaCha20
Elliptic-curve cryptography
Security should not rely on keeping the algorithm secret.
A well-designed cryptographic system assumes that attackers may know exactly which algorithm is being used.
The secret should normally be the cryptographic key.
This principle is important because proprietary or hidden encryption methods are not automatically more secure.
What Is AES-256 Encryption?
AES-256 refers to AES encryption using a 256-bit key.
The extremely large number of possible keys makes exhaustive brute-force searching impractical with conventional computing technology when AES-256 is correctly implemented.
However, the words “AES-256” alone do not guarantee that a product or system is secure.
Security also depends on factors such as:
How keys are generated
Where keys are stored
Authentication methods
Encryption mode
Software implementation
Hardware implementation
Password strength
Device security
Access controls
Strong encryption can still be undermined by weak key management.
What Is RSA Encryption?
RSA is a well-known public-key cryptographic system.
Unlike AES, which is symmetric, RSA uses a public and private key pair.
RSA has historically been used for purposes including:
Key exchange
Digital signatures
Secure communications
Certificates
RSA key sizes are significantly larger than AES key sizes because the algorithms rely on completely different mathematical security properties.
This is why comparing something such as “AES-256” directly with “RSA-2048” based purely on the numbers would be misleading.
Encryption and Digital Signatures
Encryption and digital signatures are also different concepts.
Encryption primarily protects confidentiality.
Digital signatures are primarily used to provide evidence relating to:
Authenticity
Integrity
Origin
A digital signature can help a recipient verify that data was signed using a particular private key and that the signed information has not subsequently been modified.
Public-key cryptography makes this possible.
For organisations handling sensitive files and communications, confidentiality and authenticity may both be important.
Why Encryption Keys Are So Important
Strong encryption with poor key management is still vulnerable
Cryptographic keys are among the most important parts of an encrypted system.
If someone obtains the correct decryption key, they may not need to attack the encryption algorithm at all.
Organisations therefore need to think carefully about:
Key generation
Key storage
Key distribution
Key rotation
Key backup
Key revocation
Access control
Key destruction
Keys should not simply be stored alongside encrypted information without suitable protection.
Otherwise, stealing the storage system could potentially provide an attacker with both the encrypted files and the information needed to decrypt them.
Passwords and Encryption Keys Are Not the Same Thing
Users often interact with encrypted systems through passwords or PIN codes.
However, the password itself may not be the encryption key.
Instead, the system may process the password through a key derivation mechanism to generate or unlock cryptographic material.
This is one reason why password strength remains important.
A very strong encryption algorithm can still be exposed if an attacker can easily guess the password used to unlock it.
Long, unique passwords and appropriate authentication controls are therefore important parts of an overall security strategy.
What Does Encryption Protect Against?
Encryption is particularly useful when information may be accessed by an unauthorised person.
Examples include:
Stolen devices
If a laptop, external drive or USB storage device is stolen, encryption can prevent straightforward access to the files.
Network interception
Encrypted communications can prevent someone monitoring a network from easily reading transmitted data.
Lost storage devices
USB drives and portable hard drives are easy to misplace. Encryption reduces the consequences if the physical device falls into the wrong hands.
Unauthorised access to stored data
Encrypting databases and storage systems can add another barrier between an attacker and sensitive information.
What Encryption Does Not Protect Against
Encryption is powerful, but it is not a complete cybersecurity solution.
Malware on an unlocked computer
If malware compromises a computer while the authorised user is logged in and files are already accessible, the malware may potentially access the decrypted information.
Stolen passwords
If an attacker steals the credentials required to unlock encrypted information, the strength of the underlying encryption algorithm may become irrelevant.
Social engineering
Encryption cannot prevent users from voluntarily sending sensitive information to an attacker who successfully impersonates a trusted person.
Poor access controls
Giving too many users access to sensitive information remains a security risk even when the underlying storage is encrypted.
Weak endpoints
Information often has to be decrypted before a legitimate user can read it. Protecting those endpoints is therefore essential.
Encryption should be considered part of a broader security system rather than a replacement for other security controls.
Why Organisations Use Encryption
Businesses and government organisations may hold information that could cause serious consequences if exposed.
This includes:
Intellectual property
Financial information
Employee records
Customer databases
Operational plans
Investigation material
Confidential communications
Security information
Encryption can therefore form part of:
Cybersecurity strategies
Data protection programmes
Secure communications
Access-control systems
Backup strategies
Incident-response planning
The objective is often to make sure that obtaining a device or file does not automatically mean obtaining access to the information inside it.
Encryption for Backups
Backups frequently contain the same sensitive information as production systems.
In some cases, they may contain even more because multiple historical versions of files are retained.
Encrypting backup data can therefore be just as important as encrypting the original information.
Organisations should consider protection for:
Local backups
External drives
Off-site backups
Cloud backups
Archived information
The encryption keys must also be managed carefully. Losing the only key capable of decrypting a backup may make the backup permanently unusable.
Encryption and Mobile Devices
Smartphones and tablets contain significant amounts of personal and corporate information.
This can include:
Emails
Messages
Photographs
Authentication tokens
Documents
Contact information
Cloud account access
Modern mobile operating systems frequently incorporate encryption into their security architecture.
However, device security still depends on factors such as authentication, software updates and how the device is configured.
A strong screen lock and good access controls remain important even when storage encryption is enabled.
Is Encryption Unbreakable?
No security technology should automatically be described as completely unbreakable.
A strong modern cryptographic algorithm may be computationally impractical to attack directly, but attackers frequently target weaknesses around the encryption instead.
For example, they may attempt to:
Steal the password.
Capture the encryption key.
Exploit vulnerable software.
Infect the endpoint with malware.
Trick the user.
Access files while the system is unlocked.
Therefore, the practical strength of an encrypted system depends on much more than the mathematical encryption algorithm.
Encryption and Quantum Computing
Quantum computing has created considerable discussion around the future of cryptography.
A sufficiently powerful fault-tolerant quantum computer could threaten some widely used public-key cryptographic systems.
This has driven research and development in post-quantum cryptography, which focuses on cryptographic algorithms designed to resist both conventional and quantum attacks.
Symmetric encryption is affected differently from many public-key systems, and larger symmetric key sizes provide substantial security margins.
For organisations handling information that must remain confidential for many years, the development of post-quantum cryptography is increasingly relevant.
Common Encryption Mistakes
Using outdated cryptographic systems
Older algorithms and protocols may no longer provide an appropriate level of security.
Cryptographic technologies should therefore be reviewed periodically.
Creating custom encryption
Designing secure cryptographic algorithms is extremely difficult.
Organisations should generally rely on established, publicly analysed cryptographic technologies rather than creating proprietary encryption methods without specialist expertise.
Poor key storage
Storing the encryption key next to the encrypted information can undermine the entire system.
Weak passwords
If a weak password protects a powerful encryption system, attackers may focus on guessing the password instead of attacking the encryption itself.
Forgetting about backups
Encrypting laptops while leaving unencrypted copies of the same files on portable backup drives creates an obvious weakness.
How to Choose an Encryption Solution
The appropriate encryption method depends on what needs to be protected.
Start by considering:
What information needs protection?
Highly confidential documents may require stronger controls than ordinary public information.
Where is the information stored?
Protection may be required across computers, servers, USB drives, mobile devices and backups.
Does the information need to be transported?
Portable encrypted storage may be appropriate when sensitive files need to move between physically separated systems.
Who needs access?
Access should be limited to authorised users.
How will encryption keys be managed?
Key management should be planned before large quantities of important information are encrypted.
What happens if credentials are lost?
A recovery strategy may be necessary, particularly for business-critical information.
Frequently Asked Questions About Encryption
What is the simple definition of encryption?
Encryption is the process of converting readable information into unreadable ciphertext using a cryptographic algorithm and key. The information can then be decrypted by an authorised party with the appropriate key.
What is an example of encryption?
Encrypting files on a USB drive is one example. If someone steals the device, the stored information should remain unreadable unless they can successfully authenticate and decrypt the files.
What are the two main types of encryption?
The two major categories are symmetric encryption and asymmetric encryption. Symmetric encryption typically uses one secret key, while asymmetric cryptography uses a public and private key pair.
What is AES encryption?
AES stands for Advanced Encryption Standard. It is a widely used symmetric encryption algorithm available with 128-, 192- and 256-bit keys.
What is end-to-end encryption?
End-to-end encryption protects information from the sender’s device until it reaches the intended recipient’s device, reducing the ability of intermediaries to read the communication.
Is hashing encryption?
No. Encryption is designed to be reversible with the correct key. Cryptographic hashing is generally designed as a one-way process used for purposes such as integrity checking and password verification.
Is Base64 encryption?
No. Base64 is an encoding system rather than an encryption algorithm. Encoded information can easily be converted back without a secret cryptographic key.
Can encrypted data be hacked?
Encryption significantly increases the difficulty of accessing protected information, but attackers may target passwords, encryption keys, software vulnerabilities or unlocked devices rather than attempting to break the encryption algorithm directly.
What is encrypted storage?
Encrypted storage refers to storage systems or devices that use cryptography to protect stored information. Examples include encrypted USB drives, hard drives, SSDs and secure storage systems.
Why is encryption important?
Encryption protects the confidentiality of information. Even if an unauthorised person obtains a copy of encrypted data, they should not be able to interpret it without the appropriate key.
Summary
The definition of encryption is the transformation of readable plaintext into unreadable ciphertext using a cryptographic algorithm and key. Only an authorised person or system with the correct cryptographic information should be able to convert the data back into its readable form.
Encryption can protect information stored on computers, servers, mobile devices, USB drives and backup systems. It can also secure information while it is travelling across networks.
There are two major categories of encryption. Symmetric encryption uses a shared secret key and is highly efficient for protecting large quantities of data. Asymmetric cryptography uses public and private keys and plays an important role in secure communications, authentication, digital signatures and key exchange.
Technologies such as AES, public-key cryptography, TLS, full-disk encryption and end-to-end encryption are therefore fundamental parts of modern cybersecurity.
However, encryption should never be viewed in isolation. Strong cryptography can still be undermined by poor passwords, stolen keys, malware, weak endpoints or inadequate access controls. Effective security combines encryption with proper key management, authentication, physical security, secure storage and appropriate cybersecurity procedures.
Ultimately, encryption is about ensuring that possessing data does not automatically mean being able to read it. Whether the information is stored on an encrypted drive, transmitted through a secure network or exchanged through an encrypted communication system, cryptography provides an essential layer between sensitive information and unauthorised access.
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The definition of encryption
Introduction
The definition of encryption is the process of transforming readable information into an unreadable format so that it can only be accessed by someone who has the correct key or authorization to decrypt it. Encryption is one of the fundamental technologies behind modern digital security and is used to protect everything from personal messages and passwords to business files, payment information, government communications, and stored data.
Whenever information is transmitted across a network or stored on a computer, smartphone, server, USB drive, or cloud platform, there is a possibility that an unauthorized person could gain access to it. Encryption reduces that risk by making the information unintelligible without the appropriate cryptographic key.
However, encryption is a broader subject than simply “scrambling” data. There are different encryption methods, algorithms, key structures, security levels, and practical applications.
In this guide, we go through the definition of encryption, explain how encryption works, compare symmetric and asymmetric encryption, look at encryption for stored and transmitted data, and explain concepts such as encryption keys, AES, RSA, end-to-end encryption, hashing, and encrypted storage.
What Is the Definition of Encryption?
Encryption explained in simple terms
Encryption converts information known as plaintext into an unreadable form known as ciphertext.
For example, imagine a document containing:
Before encryption, anyone who gains access to the document could potentially read the information.
After encryption, the information may appear as an unintelligible sequence of characters and data. To convert that ciphertext back into readable information, the correct decryption process and cryptographic key are required.
The basic process therefore looks like this:
Encryption does not necessarily prevent someone from stealing or copying data. Instead, its primary purpose is to make the stolen information unusable to anyone who does not possess the required key.
Why is encryption important?
Modern organisations generate and store enormous quantities of sensitive information.
This can include:
Without adequate protection, anyone who gains access to a device or network could potentially read this information.
Encryption provides an additional security layer by protecting the content itself.
How Does Encryption Work?
Plaintext and ciphertext
Two fundamental terms in cryptography are plaintext and ciphertext.
Plaintext is the original readable information.
Ciphertext is the encrypted version.
An encryption algorithm performs mathematical operations on the plaintext together with an encryption key. The resulting ciphertext should be extremely difficult to convert back into plaintext without the appropriate key.
Good modern encryption is designed so that simply knowing which algorithm was used should not be enough to recover the information.
The security instead depends heavily on the cryptographic key.
What is an encryption key?
An encryption key is a value used by a cryptographic algorithm when encrypting or decrypting information.
You can think of the key as the secret component that determines how information is transformed.
Modern encryption keys are usually long sequences of bits rather than traditional passwords.
For example, encryption systems may use keys that are:
The appropriate key length depends on the encryption technology being used.
Generally, a larger key space makes brute-force guessing more difficult, although key length alone does not determine whether an encryption system is secure.
The strength of the algorithm, implementation, key generation and key management are also extremely important.
The Two Main Types of Encryption
Encryption is commonly divided into two major categories:
Both protect information, but they operate differently.
What Is Symmetric Encryption?
One key for encryption and decryption
Symmetric encryption uses the same secret key, or closely related secret information, to encrypt and decrypt the data.
The process can be simplified as:
Data + Secret Key → Encrypted Data
The recipient then uses the same secret key to decrypt the information.
Symmetric encryption is generally very fast, making it particularly useful when large amounts of data need to be encrypted.
It is commonly used for:
What is AES encryption?
One of the best-known symmetric encryption algorithms is AES, which stands for Advanced Encryption Standard.
AES supports key sizes including:
The numbers refer to the key length.
AES-256 is widely associated with high-security applications because of its large key space and strong cryptographic design when correctly implemented.
AES can be used to protect stored files, encrypted drives, communication systems and many other types of digital information.
What Is Asymmetric Encryption?
Public and private keys
Asymmetric encryption uses two related cryptographic keys rather than one shared secret key.
These are known as:
The public key can be distributed to other people.
The private key should remain secret.
In a simplified encryption scenario, information encrypted with someone’s public key can only be decrypted using the corresponding private key.
This creates an important advantage.
Two people do not necessarily need to exchange the same secret key before communicating securely.
Where is asymmetric cryptography used?
Public-key cryptography is used extensively in modern digital infrastructure.
Applications include:
Algorithms associated with public-key cryptography include RSA and cryptographic systems based on elliptic curves.
Symmetric vs Asymmetric Encryption
Both encryption methods have advantages.
Symmetric encryption is typically faster and better suited to encrypting large amounts of information.
Asymmetric cryptography solves important problems involving identity, authentication and secure key exchange.
In practice, modern security systems frequently combine both technologies.
For example, a secure connection may initially use asymmetric cryptographic techniques to establish trust and exchange secret information. The actual flow of data can then be protected using faster symmetric encryption.
This combination provides both security and performance.
What Is Encryption at Rest?
Protecting stored information
Encryption at rest refers to encrypting information while it is stored.
This can include data stored on:
The objective is to prevent someone from simply accessing the storage device and reading its contents.
For example, if an unencrypted laptop is stolen, someone may attempt to remove the drive and access the files from another computer.
If the drive is properly encrypted, accessing the physical storage device does not automatically provide access to the information stored on it.
What Is Full-Disk Encryption?
Full-disk encryption protects most or all of the information stored on a drive.
Instead of individually encrypting selected documents, the entire storage system is protected.
When the authorised user unlocks the device, information can be decrypted as required.
Without the appropriate authentication or cryptographic key, the stored information should remain unreadable.
Full-disk encryption is particularly valuable for:
However, full-disk encryption does not solve every security problem.
If an attacker gains access while the computer is already unlocked, encryption may not prevent them from accessing information through the active operating system.
What Is Encrypted Storage?
Encrypted storage refers to storage devices or systems designed to protect stored information using encryption.
This can include:
Some products rely primarily on software encryption, while others incorporate dedicated security hardware.
Hardware-based encrypted storage may include features such as:
Encrypted storage can be particularly useful when sensitive data needs to be transported physically.
What Is Encryption in Transit?
Encryption in transit protects information while it moves between systems.
Examples include data travelling between:
Without encryption, someone monitoring the network may potentially be able to intercept information.
Encryption makes intercepted traffic significantly more difficult to interpret.
What Is TLS Encryption?
TLS stands for Transport Layer Security.
It is one of the technologies used to secure communications across the internet.
When you visit a website using HTTPS, TLS is typically used to establish a secure connection between your browser and the website’s server.
TLS can provide several important protections, including:
This is why HTTPS is particularly important for websites handling passwords, personal information or payment details.
What Is End-to-End Encryption?
End-to-end encryption, often abbreviated E2EE, is designed so that information is encrypted on the sender’s device and only decrypted by the intended recipient.
Ideally, intermediaries transporting the communication cannot read the content.
This is commonly associated with secure messaging services.
Imagine Alice sends Bob a message.
With properly implemented end-to-end encryption:
A server responsible for delivering the message should not possess the key required to read the protected content.
This differs from systems where data is encrypted between the user and a company’s server but decrypted by the service provider before being encrypted again for delivery.
Encryption vs Hashing
Is hashing the same as encryption?
No.
Hashing and encryption are related to information security but serve different purposes.
Encryption is designed to be reversible.
Encrypted information can be converted back into plaintext when the correct key is available.
Hashing is normally designed to work in one direction.
A hash function takes information and produces a fixed-size output known as a hash or digest.
Hashing is commonly used for:
A properly designed cryptographic hash should not provide a straightforward method for recovering the original input from the hash.
Therefore:
Encryption protects confidentiality.
Hashing is commonly used for verification and integrity-related purposes.
The two concepts should not be treated as interchangeable.
Encryption vs Encoding
Encoding is also frequently confused with encryption.
Encoding changes information from one representation into another, usually so that a system can store or transmit it correctly.
For example, Base64 is an encoding method.
Encoding does not provide meaningful cryptographic confidentiality because anyone who knows the encoding format can reverse it.
Encryption, on the other hand, relies on cryptographic algorithms and keys.
This is an important distinction when assessing whether data is actually protected.
What Is a Cryptographic Algorithm?
A cryptographic algorithm defines the mathematical process used to encrypt or decrypt information.
Modern cryptographic algorithms are carefully designed and extensively analysed.
Examples commonly associated with encryption and public-key cryptography include:
Security should not rely on keeping the algorithm secret.
A well-designed cryptographic system assumes that attackers may know exactly which algorithm is being used.
The secret should normally be the cryptographic key.
This principle is important because proprietary or hidden encryption methods are not automatically more secure.
What Is AES-256 Encryption?
AES-256 refers to AES encryption using a 256-bit key.
The extremely large number of possible keys makes exhaustive brute-force searching impractical with conventional computing technology when AES-256 is correctly implemented.
However, the words “AES-256” alone do not guarantee that a product or system is secure.
Security also depends on factors such as:
Strong encryption can still be undermined by weak key management.
What Is RSA Encryption?
RSA is a well-known public-key cryptographic system.
Unlike AES, which is symmetric, RSA uses a public and private key pair.
RSA has historically been used for purposes including:
RSA key sizes are significantly larger than AES key sizes because the algorithms rely on completely different mathematical security properties.
This is why comparing something such as “AES-256” directly with “RSA-2048” based purely on the numbers would be misleading.
Encryption and Digital Signatures
Encryption and digital signatures are also different concepts.
Encryption primarily protects confidentiality.
Digital signatures are primarily used to provide evidence relating to:
A digital signature can help a recipient verify that data was signed using a particular private key and that the signed information has not subsequently been modified.
Public-key cryptography makes this possible.
For organisations handling sensitive files and communications, confidentiality and authenticity may both be important.
Why Encryption Keys Are So Important
Strong encryption with poor key management is still vulnerable
Cryptographic keys are among the most important parts of an encrypted system.
If someone obtains the correct decryption key, they may not need to attack the encryption algorithm at all.
Organisations therefore need to think carefully about:
Keys should not simply be stored alongside encrypted information without suitable protection.
Otherwise, stealing the storage system could potentially provide an attacker with both the encrypted files and the information needed to decrypt them.
Passwords and Encryption Keys Are Not the Same Thing
Users often interact with encrypted systems through passwords or PIN codes.
However, the password itself may not be the encryption key.
Instead, the system may process the password through a key derivation mechanism to generate or unlock cryptographic material.
This is one reason why password strength remains important.
A very strong encryption algorithm can still be exposed if an attacker can easily guess the password used to unlock it.
Long, unique passwords and appropriate authentication controls are therefore important parts of an overall security strategy.
What Does Encryption Protect Against?
Encryption is particularly useful when information may be accessed by an unauthorised person.
Examples include:
Stolen devices
If a laptop, external drive or USB storage device is stolen, encryption can prevent straightforward access to the files.
Network interception
Encrypted communications can prevent someone monitoring a network from easily reading transmitted data.
Lost storage devices
USB drives and portable hard drives are easy to misplace. Encryption reduces the consequences if the physical device falls into the wrong hands.
Unauthorised access to stored data
Encrypting databases and storage systems can add another barrier between an attacker and sensitive information.
What Encryption Does Not Protect Against
Encryption is powerful, but it is not a complete cybersecurity solution.
Malware on an unlocked computer
If malware compromises a computer while the authorised user is logged in and files are already accessible, the malware may potentially access the decrypted information.
Stolen passwords
If an attacker steals the credentials required to unlock encrypted information, the strength of the underlying encryption algorithm may become irrelevant.
Social engineering
Encryption cannot prevent users from voluntarily sending sensitive information to an attacker who successfully impersonates a trusted person.
Poor access controls
Giving too many users access to sensitive information remains a security risk even when the underlying storage is encrypted.
Weak endpoints
Information often has to be decrypted before a legitimate user can read it. Protecting those endpoints is therefore essential.
Encryption should be considered part of a broader security system rather than a replacement for other security controls.
Why Organisations Use Encryption
Businesses and government organisations may hold information that could cause serious consequences if exposed.
This includes:
Encryption can therefore form part of:
The objective is often to make sure that obtaining a device or file does not automatically mean obtaining access to the information inside it.
Encryption for Backups
Backups frequently contain the same sensitive information as production systems.
In some cases, they may contain even more because multiple historical versions of files are retained.
Encrypting backup data can therefore be just as important as encrypting the original information.
Organisations should consider protection for:
The encryption keys must also be managed carefully. Losing the only key capable of decrypting a backup may make the backup permanently unusable.
Encryption and Mobile Devices
Smartphones and tablets contain significant amounts of personal and corporate information.
This can include:
Modern mobile operating systems frequently incorporate encryption into their security architecture.
However, device security still depends on factors such as authentication, software updates and how the device is configured.
A strong screen lock and good access controls remain important even when storage encryption is enabled.
Is Encryption Unbreakable?
No security technology should automatically be described as completely unbreakable.
A strong modern cryptographic algorithm may be computationally impractical to attack directly, but attackers frequently target weaknesses around the encryption instead.
For example, they may attempt to:
Therefore, the practical strength of an encrypted system depends on much more than the mathematical encryption algorithm.
Encryption and Quantum Computing
Quantum computing has created considerable discussion around the future of cryptography.
A sufficiently powerful fault-tolerant quantum computer could threaten some widely used public-key cryptographic systems.
This has driven research and development in post-quantum cryptography, which focuses on cryptographic algorithms designed to resist both conventional and quantum attacks.
Symmetric encryption is affected differently from many public-key systems, and larger symmetric key sizes provide substantial security margins.
For organisations handling information that must remain confidential for many years, the development of post-quantum cryptography is increasingly relevant.
Common Encryption Mistakes
Using outdated cryptographic systems
Older algorithms and protocols may no longer provide an appropriate level of security.
Cryptographic technologies should therefore be reviewed periodically.
Creating custom encryption
Designing secure cryptographic algorithms is extremely difficult.
Organisations should generally rely on established, publicly analysed cryptographic technologies rather than creating proprietary encryption methods without specialist expertise.
Poor key storage
Storing the encryption key next to the encrypted information can undermine the entire system.
Weak passwords
If a weak password protects a powerful encryption system, attackers may focus on guessing the password instead of attacking the encryption itself.
Forgetting about backups
Encrypting laptops while leaving unencrypted copies of the same files on portable backup drives creates an obvious weakness.
How to Choose an Encryption Solution
The appropriate encryption method depends on what needs to be protected.
Start by considering:
What information needs protection?
Highly confidential documents may require stronger controls than ordinary public information.
Where is the information stored?
Protection may be required across computers, servers, USB drives, mobile devices and backups.
Does the information need to be transported?
Portable encrypted storage may be appropriate when sensitive files need to move between physically separated systems.
Who needs access?
Access should be limited to authorised users.
How will encryption keys be managed?
Key management should be planned before large quantities of important information are encrypted.
What happens if credentials are lost?
A recovery strategy may be necessary, particularly for business-critical information.
Frequently Asked Questions About Encryption
What is the simple definition of encryption?
Encryption is the process of converting readable information into unreadable ciphertext using a cryptographic algorithm and key. The information can then be decrypted by an authorised party with the appropriate key.
What is an example of encryption?
Encrypting files on a USB drive is one example. If someone steals the device, the stored information should remain unreadable unless they can successfully authenticate and decrypt the files.
What are the two main types of encryption?
The two major categories are symmetric encryption and asymmetric encryption. Symmetric encryption typically uses one secret key, while asymmetric cryptography uses a public and private key pair.
What is AES encryption?
AES stands for Advanced Encryption Standard. It is a widely used symmetric encryption algorithm available with 128-, 192- and 256-bit keys.
What is end-to-end encryption?
End-to-end encryption protects information from the sender’s device until it reaches the intended recipient’s device, reducing the ability of intermediaries to read the communication.
Is hashing encryption?
No. Encryption is designed to be reversible with the correct key. Cryptographic hashing is generally designed as a one-way process used for purposes such as integrity checking and password verification.
Is Base64 encryption?
No. Base64 is an encoding system rather than an encryption algorithm. Encoded information can easily be converted back without a secret cryptographic key.
Can encrypted data be hacked?
Encryption significantly increases the difficulty of accessing protected information, but attackers may target passwords, encryption keys, software vulnerabilities or unlocked devices rather than attempting to break the encryption algorithm directly.
What is encrypted storage?
Encrypted storage refers to storage systems or devices that use cryptography to protect stored information. Examples include encrypted USB drives, hard drives, SSDs and secure storage systems.
Why is encryption important?
Encryption protects the confidentiality of information. Even if an unauthorised person obtains a copy of encrypted data, they should not be able to interpret it without the appropriate key.
Summary
The definition of encryption is the transformation of readable plaintext into unreadable ciphertext using a cryptographic algorithm and key. Only an authorised person or system with the correct cryptographic information should be able to convert the data back into its readable form.
Encryption can protect information stored on computers, servers, mobile devices, USB drives and backup systems. It can also secure information while it is travelling across networks.
There are two major categories of encryption. Symmetric encryption uses a shared secret key and is highly efficient for protecting large quantities of data. Asymmetric cryptography uses public and private keys and plays an important role in secure communications, authentication, digital signatures and key exchange.
Technologies such as AES, public-key cryptography, TLS, full-disk encryption and end-to-end encryption are therefore fundamental parts of modern cybersecurity.
However, encryption should never be viewed in isolation. Strong cryptography can still be undermined by poor passwords, stolen keys, malware, weak endpoints or inadequate access controls. Effective security combines encryption with proper key management, authentication, physical security, secure storage and appropriate cybersecurity procedures.
Ultimately, encryption is about ensuring that possessing data does not automatically mean being able to read it. Whether the information is stored on an encrypted drive, transmitted through a secure network or exchanged through an encrypted communication system, cryptography provides an essential layer between sensitive information and unauthorised access.
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