How to encrypt and decrypt data with Hibernate

(Last Updated On: June 6, 2018)

Introduction

Today, one of my Twitter followers sent me the following StackOverflow question, and, while answering it, I realized that it definitely deserves a post of its own.

In this post, I will explain how you can encrypt and decrypt data with Hibernate.

PostgreSQL crypto module

Because the StackOverflow question mentions PostgreSQL, we first need to enable the pgcrypto extension. For this purpose, we need to execute the following statement:

CREATE EXTENSION pgcrypto;

The pgcrypto will allow us to use the pgp_sym_encrypt and pgp_sym_decrypt functions.

Domain Model

Assuming we have the following entity:

vault

The storage column needs to be encrypted upon being written and decrypted during a read operation.

@ColumnTransformer annotation to the rescue!

Luckily, Hibernate offers the @ColumnTransformer annotation which was added exactly for this type of scenarios.

Therefore, the Vault mapping looks like this:

@Entity(name = "Vault")
public class Vault {

    @Id
    private Long id;

    @ColumnTransformer(
        read =  "pgp_sym_decrypt(" +
                "    storage, " +
                "    current_setting('encrypt.key')" +
                ")",
        write = "pgp_sym_encrypt( " +
                "    ?, " +
                "    current_setting('encrypt.key')" +
                ") "
    )
    @Column(columnDefinition = "bytea")
    private String storage;

    //Getter and setters omitted for brevity
}

Because hard-coding the encryption key in the mapping does not sound like a very good idea, we will use the PostgreSQL support for user-defined settings instead.

So, the encrypt.key is stored in postgresql.conf configuration file:

encrypt.key = 'Wow! So much security.'

Testing time

When persisting a Vault entity:

Vault user = new Vault();
user.setId(1L);
user.setStorage("my_secret_key");

entityManager.persist(user);

Hibernate is going to encrypt the column, so if you select it with a native SQL query:

String encryptedStorage = (String) entityManager
.createNativeQuery(
    "select encode(storage, 'base64') " +
    "from Vault " +
    "where id = :id")
.setParameter("id", 1L)
.getSingleResult();

LOGGER.info("Encoded storage: {}", encryptedStorage);

You are going to see a value like this:

-- Encoded storage: ww0EBwMC3If4VmIUn2x+0j4BKrKR9j0GFpg87Qoz/v21etflhGPE6l9p7O5Sz9yOhynbvr+gwncW

However, when loading the entity with Hibernate:

Vault vault = entityManager.find( Vault.class, 1L );
assertEquals("my_secret_key", vault.getStorage());

The storage attribute is properly decrypted back to the original value.

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Conclusion

As I explained in my book, High-Performance Java Persistence, if you don’t take advantage of the underlying JPA provider or relational database capabilities, you are going to lose lots of features, like easy-peasy encryption.

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4 thoughts on “How to encrypt and decrypt data with Hibernate

  1. How secure is it to store the encryption key on a database where the data is encrypted? If someone gained access to the DB, would they not be able to retrieve the key and decrypt all sensitive information?

    1. If they get access to the OS, it’s probably very serious anyway. However, you can get the key as an SQL Session variable provided by the database connection. That can be located from an encrypted source.

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