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Encrypting Data at Rest – Comparison between PGP and AES

Storing data at Rest in a data integration tool is critical for both data security and compliance with industry standards. This gets more significant if the data is stored at LAN. Therefore, it is imperative to encrypt the data at rest to save it from misuse or theft.

Why Is It Important to Encrypt Data at Rest?

Encrypting data at rest is of paramount importance for several key reasons:

  1. Data Security: Encrypting data at rest protects it from unauthorized access. Even if a malicious actor gains physical access to storage devices, encrypted data remains unreadable without the proper decryption keys.
  2. Compliance Requirements: Many industry regulations and data protection laws, such as GDPR and HIPAA, mandate the encryption of sensitive data at rest. Failure to comply with these regulations can result in severe legal and financial consequences.
  3. Preventing Data Theft: In the event of a data breach or theft of storage devices, encrypted data remains confidential and secure. This prevents the exposure of sensitive information, mitigating reputational damage and potential legal liabilities.
  4. Protecting Confidentiality: Data encryption ensures the confidentiality of sensitive information, including personal and financial data, trade secrets, and intellectual property. This is critical for businesses, as the loss or compromise of such data can be detrimental.
  5. Risk Management: Encrypting data at rest is a proactive measure to mitigate risks. It serves as a last line of defense, providing an additional layer of protection even when other security measures may fail.
  6. Data in the Cloud: As organizations increasingly move data to cloud-based storage services, encrypting data at rest is essential to secure data stored in remote servers, reducing the risk of unauthorized access by cloud service providers or external attackers.
  7. Data Integrity: Some encryption methods also include data integrity checks, ensuring that data remains unchanged and uncorrupted during storage. This is crucial for maintaining data accuracy and reliability.
  8. Third-Party Vendors: When businesses rely on third-party vendors or data center providers for storage, encrypting data at rest adds an extra level of security, reducing reliance on the vendor’s security measures.

How to Encrypt Data at Rest?

Let’s talk about the encryption of data at rest in the context of data integration applications with an example. Firstly, we should understand that encryption on any system requires three components:

(1) Data that needs to be encrypted

(2) A method to encrypt the data using a cryptographic algorithm

(3) Encryption keys to be used in conjunction with the data and the algorithm

Programming languages like JAVA provide libraries with a wide range of cryptographic algorithms, such as Advanced Encryption Standard (AES). Choosing the right algorithm involves analysis and research based on security and performance.

A data integration tool that companies use for data transactions generally handles the sensitive information of their clients. This information can be as generic as SSN or as confidential as Credit Card Details. The tool stores data for processing on the file system, and an application interacts with it through a Java IO API. In this case, the file needs to be encrypted before it persists on the file system by the tool and then decrypts before the application reads it for parsing and processing.

What Is PGP Encryption?

To secure data, we may look for a good algorithm that can help in encrypting it at rest. The commonly thought-after method for encrypting and decrypting data is PGP (Pretty Good Privacy). PGP uses symmetric and asymmetric keys to encrypt data being transferred across networks. Asymmetric encryption uses two different keys for encryption and decryption and both keys are derived from one another and created at the same time. These are divided into and referred to as public and private key that makes up the key pair. Data is only encrypted with a public key and thus can only be decrypted with the matching private key. PGP provides additional security that prevents anyone who has only the public key from decrypting data that was previously encrypted with it. Another benefit of asymmetric encryption is that it allows authentication checks. This seemed to be a viable option but with some limitations. Take a look at the public key encryption demo depicted below.

PGP is mainly beneficial in cases when sensitive data is exchanged between partners; essentially when the information is shared over the network. It works fine when you work to attain public key cryptography. However, PGP requires more computational resources which can lead to performance issues and make the process cumbersome and slow. Hence, one must be aware of other algorithms such as AES for encryption. Let’s explore AES vs PGP  to know how these are different from each

What is AES Encryption?

AES is a symmetric key encryption algorithm that essentially lets the key be used for encryption and decryption of data. A computer program takes the clear text processes it through an encryption key and returns the ciphertext.

AES Encryption (Advanced Encryption Standard) is a widely adopted symmetric encryption algorithm used to secure sensitive data. It transforms plaintext into ciphertext using a secret encryption key, which is the same for both encryption and decryption. AES operates on fixed-size data blocks (most commonly 128 bits) and supports key lengths of 128, 192, and 256 bits. Chosen as the U.S. federal government standard in 2001, AES is known for its strong security, efficient performance, and resistance to attacks. It is used in secure communications, data protection, and various applications where data confidentiality is crucial.

PGP Vs AES: If data needs to be decrypted, the program processes it again with the same key and reproduces the clear text. It requires less computational resources as compared to PGPthat means lower performance impact. As we discuss the encryption of data at rest, AES seems to be a promising solution.

There are a few important points that need to be noted while implementing AES in the application:

1. Initialization Vector (IV): The role of IV is to insert some new randomness into the process each time a message is encrypted. This would enable the same message to be encrypted to a different ciphertext each time, but similar messages will not result in similar ciphertexts. This is the reason why IVs need to be random, but never need to be secret, they can live at the beginning of the ciphertext. There are all sorts of attacks on CBC mode when IVs are predictable. For example, many of the attacks on SSL (such as POODLE) take advantage of predictable IVs.

2. Generate AES Keys and store them in a JCEKS keystore format: JCEKS or Java Cryptography Extension KeyStore is created using the “keytool” provided with the Java JDK. Storing keys in a KeyStore can be a measure to prevent your encryption keys from being exposed. It is simple to manipulate a keystore while using the KeyTool. Keystores must be created either with a link to a new key or during an import of an existing keystore. In order to create a new key and keystore type:

keytool -genseckey -keystore aes-keystore.jck -storetype jceks -storepass mystorepass -keyalg AES -keysize 256 -alias jceksaes -keypass mykeypass

Keystore Parameters

genseckey: Generate SecretKey. This is the flag indicating the creation of a synchronous key which will become our AES key

keystore: Location of the keystore. If the keystore does not exist, the tool will create a new store. Paths can be relative or absolute but must be local

storetype: This is the type of store (JCE, PK12, JCEKS, etc). JCEKS is used to store symmetric keys (AES) not contained within a certificate.

storepass: password related to the keystore. Highly recommended to create a strong passphrase for the keystore

Key Parameters

keyalg: algorithm used to create the key (AES)

keysize: size of the key (128, 192, 256, etc)

alias: alias given to the newly created key

keypass: password protecting the use of the key

3. Cipher Instance: While getting Cipher instance in Java, there is an option to provide the security provider such as BouncyCastle. Instead of recreating the provider instance multiple times (which is a bad idea), try using Security.addProvider(new BouncyCastleProvider()) and then using the name “BC”. This approach will save you few milliseconds (~200) for each call to get the Cipher instance.

So, instead of using:

Cipher.getInstance(algorithm, new


use this:

// required only once

Security.addProvider(new BouncyCastleProvider());

Cipher.getInstance(algorithm, “BC”);