How to encrypt a column using nifi

Which repository are you referring to? An internal NiFi repository or the location your flow is writing data to?

You can use the EncryptContent processor to encrypt the whole content of the flowfile, but there isn't an easy way to a single field of a record. To do this you will have to use something like the ScriptedTransformRecord and provide a script that encrypts parts of your data.

Here's an example of using ScriptedTransformRecord with a Groovy script to encrypt the field "name":

import javax.crypto.Cipher
import javax.crypto.SecretKey
import javax.crypto.SecretKeyFactory
import javax.crypto.spec.IvParameterSpec
import javax.crypto.spec.PBEKeySpec
import javax.crypto.spec.SecretKeySpec
import java.security.Key
import java.security.spec.KeySpec

String encryptionKey = "#{encryption.key}"
Key aesKey = new SecretKeySpec(encryptionKey.getBytes("UTF-8"), "AES")
Cipher cipher = Cipher.getInstance("AES/ECB/PKCS5Padding")
cipher.init(Cipher.ENCRYPT_MODE, aesKey)
record.setValue("name", cipher.doFinal(record.getValue("name").getBytes("UTF-8")).encodeBase64())
record

 To decrypt it you could use:

import javax.crypto.Cipher
import javax.crypto.SecretKey
import javax.crypto.SecretKeyFactory
import javax.crypto.spec.IvParameterSpec
import javax.crypto.spec.PBEKeySpec
import javax.crypto.spec.SecretKeySpec
import java.security.Key
import java.security.spec.KeySpec
import java.util.Base64

String encryptionKey = "#{encryption.key}"
Key aesKey = new SecretKeySpec(encryptionKey.getBytes("UTF-8"), "AES")
Cipher cipher = Cipher.getInstance("AES/ECB/PKCS5Padding")
cipher.init(Cipher.DECRYPT_MODE, aesKey)
record.setValue("name", cipher.doFinal(Base64.getDecoder().decode(record.getValue("name"))))
record

The encrypt key is specified through a NiFi parameter called encryption.key.

Cheers,

André