What is encryption and why is it used?
Encryption is the process of encoding data or information in such a way that only authorized parties can access it. The data is encrypted by applying a cipher algorithm that scrambles the data into an unreadable format called ciphertext. Decryption is the reverse process which converts the ciphertext back into readable plaintext.
Encryption is commonly used to protect sensitive information stored on computer systems, transmitted across networks like the internet, and transported through portable storage devices. It ensures that only those who have the correct encryption key can decrypt and access the original data. This prevents unauthorized access from cybercriminals and bad actors.
Some common reasons to encrypt data include:
- Protecting confidential personal, financial, or healthcare records
- Securing classified government and military information
- Preventing financial fraud such as identity theft
- Ensuring privacy of communications like email and instant messaging
Encryption applies to many different types of digital data including text documents, spreadsheets, databases, email messages, images, and videos. It provides a level of security and privacy when transferring or storing data digitally.
When is encryption applied to documents?
Encryption can be applied to documents in many different situations:
- To protect documents stored on hard drives, USB drives, CDs, DVDs, and other storage media.
- To secure documents sent as email attachments.
- To encode documents transferred over public Wi-Fi networks and the internet.
- To safeguard backups and archives of important documents.
- To comply with regulations like HIPAA for protecting healthcare data.
- To prevent unauthorized access when documents contain sensitive data.
Documents that often need encryption include:
- Financial statements
- Contracts and legal agreements
- Business plans
- Product designs and diagrams
- Personnel records
- Patient healthcare information
- Classified government documents
Encryption is applied through encryption software that runs on desktops, servers, cloud services, and mobile devices. This software can encrypt files and folders, entire disks and storage devices, as well as email communications.
What are the different types of encryption?
There are several types of data encryption that use different levels of security and algorithms:
This uses a shared private key to both encrypt and decrypt data. The sender encrypts data with the key and the recipient uses the same key to decrypt it. Examples are AES and 3DES.
This uses a public-private key pair for encrypting and decrypting data. The public key encrypts data and the private key decrypts it. Data encrypted with the public key can only be decrypted using the corresponding private key. Example is RSA.
This combines symmetric and asymmetric encryption. Data is encrypted with a symmetric key, and then the symmetric key is encrypted with an asymmetric public key. Provides added security benefits of both types.
This encrypts data using a password instead of encryption keys. The password acts as the secret key to encrypt and decrypt the data. Example is AES 256-bit encryption.
This allows computing on encrypted data without decrypting it first. Performs operations like search, analytics, machine learning on ciphertext. Useful when processing sensitive cloud data.
This leverages quantum physics to provide enhanced cryptographic security. Uses photons polarized in different ways to produce shared encryption keys. Provides high defense against attacks.
How does encryption work?
The encryption process uses an encryption algorithm or cipher that follows these general steps:
- The original plaintext data is encrypted using a key and encryption algorithm.
- The encryption algorithm applies a series of mathematical operations to scramble the plaintext. This produces unintelligible ciphertext.
- The encryption key is required by the algorithm to correctly encrypt and decrypt the data.
- The key and ciphertext are then transmitted or stored depending on the use case.
- To decrypt the ciphertext, the key is used with the encryption algorithm to restore the data back into plaintext.
The encryption key must be securely transmitted or shared with authorized recipients in order for them to decrypt data. The algorithm provides the mathematical obfuscation that protects the confidentiality and integrity of the data.
There are different categories of encryption algorithms:
- Symmetric algorithms use the same key to encrypt and decrypt data. Examples include AES, Blowfish, RC4.
- Asymmetric algorithms use different public and private keys for encryption and decryption. Examples include RSA, ECC, ElGamal.
- Hashing algorithms create a unique hash value or checksum from the plaintext data. Examples include MD5, SHA-1, Blake2.
Encryption key management is critical to maintain security as keys must be properly generated, distributed, stored, rotated, and revoked when compromised.
What are the standard encryption algorithms?
Some commonly used standard encryption algorithms include:
AES (Advanced Encryption Standard)
- Symmetric algorithm that uses 128, 192, or 256-bit keys.
- Adopted in 2001 by the US National Institute of Standards and Technology (NIST) as a standard algorithm.
- Used worldwide today for encrypting government, financial, and commercial data.
- Implemented in software and hardware by many vendors.
- Effective against brute force attacks.
- Asymmetric algorithm based on factoring large prime numbers.
- Uses public and private key pair for encryption and decryption.
- Widely used for secure data transmission and digital signatures.
- Provides high level of security but slower than symmetric algorithms.
- Symmetric algorithm that uses 32 to 448 bit keys.
- Designed as a fast and secure alternative to existing algorithms like DES and 3DES.
- Public domain and freely available algorithm.
- Used today in applications like data security and encryption products.
- Cryptographic hashing algorithm that produces a 256-bit hash value.
- Designed by the NSA and published by NIST as a US Federal Information Processing Standard.
- Generates an irreversible and unique hash from input data like passwords, messages, files.
- Used for verifying data integrity and digital signatures.
There are many other standard algorithms like ECC, 3DES, MD5, SHA-1, RC4 that are in use today for varied encryption use cases.
How can encryption be removed from a document?
To remove encryption from an encrypted document, you need access to the correct encryption key or password that was originally used to encrypt the document. Without the proper decryption key, it is impossible to fully decrypt the document. Some ways the encryption can be removed include:
Using the decryption key
If you have the original key used to encrypt the document, you can use it with the appropriate decryption algorithm to decrypt the document. This could be a shared secret key for symmetric encryption or the private key if public key encryption was used. Decrypting the document restores it to its original plaintext version with the encryption removed.
Using the password
For password-protected documents, supplying the correct password will allow the document to be decrypted. This password serves as the secret encryption key. Tools like Microsoft Office allow opening password-protected documents by entering the password when prompted.
Using decryption tools
There are tools and software like VeraCrypt, PGP, and GaussCrypt that can decrypt encrypted files and documents if provided the correct key. They use the appropriate decryption cipher based on the detected encryption algorithm.
Disabling encryption permissions
In the case of files encrypted using access controls, removing the encryption permissions from the user’s account will allow full access to the decrypted document.
Brute forcing the encryption key
This involves trying all possible decryption key combinations to find the correct key that decrypts the document through trial and error. This is rarely successful with modern algorithms.
However, if the document was improperly encrypted allowing parts of the plaintext to be visible, then it may be possible to exploit this vulnerability to recover sections of the document or even the full plaintext content without decrypting it. But otherwise, accessing the encrypted document’s contents is not possible without the decryption key or password.
What are the risks of removing encryption from a document?
Removing encryption from a document leads to several security risks:
- Exposes confidential data – Encrypted data is protected from unauthorized access. Removing encryption exposes the sensitive contents.
- Violates compliance regulations – Encryption is often required to meet data compliance standards like HIPAA and PCI DSS.
- Increased risk of data leaks – Unencrypted documents can more easily be accessed, copied, and distributed.
- Enables data theft – Removes a barrier preventing cybercriminals from stealing valuable information.
- Loss of data integrity – Encryption provides verification that the data has not been altered or corrupted.
- Loss of non-repudiation – Encryption provides proof of the authenticity and origin of a document which is lost when removing it.
- Escalated legal liability – Organizations may face lawsuits, fines, and reputation damage if encryption is removed from regulated data.
It is recommended to only remove encryption with careful examination of the legal, compliance, and data security ramifications. In most cases, properly encrypted documents should remain encrypted to maintain confidentiality protections.
When can you legally remove encryption from a document?
There are limited scenarios where it may be legal to remove encryption from a document:
- When you own the copyrights to the document and contents as the author.
- When you have explicit written permission from the document owner to decrypt it.
- If the document is classified as public domain material.
- If the encryption key was obtained through legal means such as public disclosure.
- When required by court order or subpoena for legal investigation or discovery.
- If mandated by government regulations for national security purposes.
- For ethical hacking or penetration testing with proper authorization.
- When conducting authorized audits or forensic analysis on organizational data.
- For repositories storing historical documents without access restrictions.
However, there are many instances where removing encryption is illegal:
- When violating copyright or intellectual property protections.
- If prohibited by laws like DMCA, HIPAA, and GLBA.
- When used for malicious hacking, corporate espionage, or competitive intelligence.
- To steal healthcare records, financial information, or other regulated data.
- When illegally obtaining or distributing proprietary information.
- To profit from the sale or distribution of decrypted data.
- When decryption defeats digital rights management protections on media.
It is best to consult legal counsel before removing any encryption, even your own, to avoid violating laws. Ethical and authorized use cases should be carefully evaluated as well.
What tools can remove encryption from documents?
There are various software tools, both paid and free, that allow removing encryption from documents when the correct encryption keys or passwords are supplied:
- Free and open source disk encryption tool.
- Decrypts documents and entire storage drives protected by AES, Serpent or Twofish algorithms.
- Supports common containers like ZIP and formats like NTFS, FAT.
- Runs on Windows, macOS, and Linux.
PGP (Pretty Good Privacy)
- Uses public-key cryptography to encrypt files, emails, directories.
- Decrypts data encrypted with PGP keys.
- Good for decrypting older PGP-encrypted data.
- Commercial encryption removal tool for documents, disks, databases, email.
- Cracks passwords using dictionary, brute force, rainbow tables.
- Recovers keys from memory and extracts encryption keys.
- Supports platform business applications like BitLocker, Office, etc.
- Set of Windows tools for removing encryption from Office documents, PDFs, disk backups.
- Offers advanced GPU acceleration for password recovery.
- Uses rainbow tables, brute force, masking attacks.
- Online cloud-based encryption and decryption for files.
- Removes password protection from PDFs, Office files, and media files.
- Uses ciphers like AES, Twofish, Serpent, and RSA.
There are also toolkits like GaussCrypt, Crypt-O-Matic, and Hash Kracker that provide a variety of encryption removal capabilities.
However, ethical usage and legal compliance must be ensured when using any encryption removal software.
Best practices for removing encryption
If removing encryption from a document is necessary, some best practices should be followed:
- Obtain legal authorization and verify regulatory compliance.
- Notify appropriate personnel like legal, compliance, and IT security teams.
- Only use encryption keys obtained through valid ownership or legal rights.
- Strictly limit access to decrypted documents to authorized eyes only.
- Store decrypted documents securely with strict access controls.
- Re-encrypt documents immediately after valid usage of decrypted contents.
- Comply with all proprietary, copyright, security standards for the data.
- Destroy the encryption keys and decrypted contents after use.
- Frequently rotate keys and re-encrypt data with improved ciphers.
- Monitor systems containing decrypted data for suspicious activity.
Removing encryption should be a meticulously controlled exception, rather than the norm, for securely stored and transmitted data. Limiting data’s exposure in decrypted form is crucial.
Encryption provides the vital protection required to secure confidential documents and data in storage and transit. Removing encryption exposes sensitive data to unauthorized access, theft, leakage, corruption, and non-compliance risks.
Obtaining the original encryption keys is necessary to decrypt documents. Even then, decryption should only be performed under legal and regulated circumstances. Proper key handling and management, limited decrypted data access, strong re-encryption, and encryption hygiene is essential to safely remove encryption when absolutely required.
Organizations and users should favour robust encryption applied correctly to sensitive documents, with decryption performed rarely in controlled scenarios to uphold security and compliance. This maintains encryption’s crucial barriers against internal and external data breaches, unauthorized disclosures, IP theft, financial crimes, and reputational damages.