{"id":51,"date":"2019-07-06T10:17:13","date_gmt":"2019-07-06T04:47:13","guid":{"rendered":"http:\/\/techieshouts.com\/?p=51"},"modified":"2022-08-09T19:08:57","modified_gmt":"2022-08-09T13:38:57","slug":"aes-encryption-and-decryption-in-java","status":"publish","type":"post","link":"https:\/\/techieshouts.com\/home\/aes-encryption-and-decryption-in-java\/","title":{"rendered":"AES Encryption and Decryption in Java"},"content":{"rendered":"\n
\"AES\"<\/figure>
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While there are many encryption and decryption algorithms available, AES is one of the robust and reliable modes of encrypting the data. The implementation can be done in many languages as there are libraries and packages available for multiple languages. <\/p>\n<\/div><\/div>\n\n\n\n

<\/p>\n\n\n\n

Creating the AES encryption\/decryption library<\/strong><\/h2>\n\n\n\n

We do not need any special library to be downloaded for creating the AES encryption\/decryption library. All we need is the javax.crypto package which is already available as a part of JDK <\/p>\n\n\n\n

import javax.crypto.Cipher;\nimport javax.crypto.spec.IvParameterSpec;\nimport javax.crypto.spec.SecretKeySpec;\nimport javax.xml.bind.DatatypeConverter;\npublic final class EncDec \n{\npublic static String encrypt(String value, String ivVal, String key) {\n    try {\n        IvParameterSpec iv = new IvParameterSpec(ivVal.getBytes(\"UTF-8\"));\n        SecretKeySpec skeySpec = new SecretKeySpec(key.getBytes(\"UTF-8\"), \"AES\");\n        Cipher cipher = Cipher.getInstance(\"AES\/CBC\/PKCS5PADDING\");\n        cipher.init(1, skeySpec, iv);\n        byte[] encrypted = cipher.doFinal(value.getBytes());\n        return DatatypeConverter.printBase64Binary(encrypted);\n    } catch (Exception ex) {\n        ex.printStackTrace();\n    }\n    return null;\n}\npublic static String decrypt(String encrypted, String ivVal, String key) {\n    try {\n        IvParameterSpec iv = new IvParameterSpec(ivVal.getBytes(\"UTF-8\"));\n        SecretKeySpec skeySpec = new SecretKeySpec(key.getBytes(\"UTF-8\"), \"AES\");\n        Cipher cipher = Cipher.getInstance(\"AES\/CBC\/PKCS5PADDING\");\n        cipher.init(2, skeySpec, iv);\n        byte[] original = cipher.doFinal(DatatypeConverter.parseBase64Binary(encrypted));\n        return new String(original);\n    } catch (Exception ex) {\n        ex.printStackTrace();\n    }\n    return null;\n}\n}<\/pre>\n\n\n\n
Now let us look into the above code by each section<\/p>\n\n\n\n
Imports required for AES Encryption<\/h2>\n\n\n\n
import javax.crypto.Cipher;\nimport javax.crypto.spec.IvParameterSpec;\nimport javax.crypto.spec.SecretKeySpec;\nimport javax.xml.bind.DatatypeConverter;<\/pre>\n\n\n\n
These are the classes required to perform encryption\/decryption. AES is using Cipher padding for performing the encryption. There are two main classes that we are using here.  IvParameterSpec will receive a byte array of the iv(initial vector).<\/p>\n\n\n\n
 IV is used along with the secret key to prevent the repetition of sequence in encryption. This will make the job of a hacker tough. <\/p>\n\n\n\n
IvParameterSpec iv = new IvParameterSpec(ivVal.getBytes(\"UTF-8\"));<\/pre>\n\n\n\n
The next one is the secret key.  Similar to IvParameterSpec the SecretKeySpec class will also accept a byte array of the secret key. Along with that, it will receive the value of the encryption type that we want to use.<\/p>\n\n\n\n
SecretKeySpec skeySpec = new SecretKeySpec(key.getBytes(\"UTF-8\"), \"AES\");<\/pre>\n\n\n\n
After this, the Cipher object will be created with the above two objects and the mode(Encryption or Decryption) is indicated with the help of the first parameter while creating the Cipher object.<\/p>\n\n\n\n
Cipher cipher = Cipher.getInstance(\"AES\/CBC\/PKCS5PADDING\");\ncipher.init(1, skeySpec, iv);<\/pre>\n\n\n\n
The different types of cipher class instances are<\/p>\n\n\n\n