Security has become a great topic of discussion in the last few years due to the recent releasing of documents from Edward Snowden and the explosion of hacking against online commerce stores like JC Penny, Sony and Target. While this post will not give you all of the tools to help prevent the use of illegally sourced data, this post will provide a starting point for building a set of tools and tactics that will help prevent the use of data by other parties.
AES encryption and decryption online tool for free.It is an aes calculator that performs aes encryption and decryption of image, text and.txt file in ECB and CBC mode with 128, 192,256 bit. The output can be base64 or Hex encoded. Dec 03, 2016 AES 256bit Encryption/Decryption and storing in the. And supports a block length of 128bits and key lengths of 128,192 and 256 bits. AES-256 encryption/decryption using Java.
This post will show how to adopt AES encryption for strings in a Java environment. It will talk about creating AES keys and storing AES keys in a JCEKS keystore format. A working example of the code in this blog is located at https://github.com/mike-ensor/aes-256-encryption-utility
It is recommended to read each section in order because each section builds off of the previous section, however, this you might want to just jump quickly jump to a particular section.
JCEKS stands for Java Cryptography Extension KeyStore and it is an alternative keystore format for the Java platform. Storing keys in a KeyStore can be a measure to prevent your encryption keys from being exposed. Java KeyStores securely contain individual certificates and keys that can be referenced by an alias for use in a Java program. Java KeyStores are often created using the 'keytool' provided with the Java JDK.
NOTE: It is strongly recommended to create a complex passcode for KeyStores to keep the contents secure. The KeyStore is a file that is considered to be public, but it is advisable to not give easy access to the file.
All encryption is governed by laws of each country and often have restrictions on the strength of the encryption. One example is that in the United States, all encryption over 128-bit is restricted if the data is traveling outside of the boarder. By default, the Java JCE implements a strength policy to comply with these rules. If a stronger encryption is preferred, and adheres to the laws of the country, then the JCE needs to have access to the stronger encryption policy. Very plainly put, if you are planning on using AES 256-bit encryption, you must install the Unlimited Strength Jurisdiction Policy Files. Without the policies in place, 256-bit encryption is not possible.
This post is focusing on the keys rather than the installation and setup of the JCE. The installation is rather simple with explicit instructions found here (NOTE: this is for JDK7, if using a different JDK, search for the appropriate JCE policy files).
When using the KeyTool manipulating a keystore is simple. Keystores must be created with a link to a new key or during an import of an existing keystore. In order to create a new key and keystore simply type:
In the example above here are the explanations for the keytool's parameters:
As it pertains to data in Java and at the most basic level, encryption is an algorithmic process used to programmatically obfuscate data through a reversible process where both parties have information pertaining to the data and how the algorithm is used. In Java encryption, this involves the use of a Cipher. A Cipher object in the JCE is a generic entry point into the encryption provider typically selected by the algorithm. This example uses the default Java provider but would also work with Bouncy Castle.
Obtaining an instance of Cipher is rather easy and the same process is required for both encryption and decryption. (NOTE: Encryption and Decryption require the same algorithm but do not require the same object instance)Once we have an instance of the Cipher, we can encrypt and decrypt data according to the algorithm. Often the algorithm will require additional pieces of information in order to encrypt/decrypt data. In this example, we will need to pass the algorithm the bytes containing the key and an initial vector (explained below).
In order to use the Cipher, we must first initialize the cipher. This step is necessary so we can provide additional information to the algorithm like the AES key and the Initial Vector (aka IV).
The SecretKeySpecification is an object containing a reference to the bytes forming the AES key. The AES key is nothing more than a specific sized byte array (256-bit for AES 256 or 32 bytes) that is generated by the keytool (see above).
There are multiple methods to create keys such as a hash including a salt, username and password (or similar). This method would utilize a SHA1 hash of the concatenated strings, convert to bytes and then truncate result to the desired size. This post will not show the generation of a key using this method or the use of a PBE key method using a password and salt. The password and/or salt usage for the keys is handled by the keytool using the inputs during the creation of new keys.
The AES algorithm also requires a second parameter called the Initialiation Vector. The IV is used in the process to randomize the encrypted message and prevent the key from easy guessing. The IV is considered a publicly shared piece of information, but again, it is not recommended to openly share the information (for example, it wouldn't be wise to post it on your company's website). When encrypting a message, it is not uncommon to prepend the message with the IV since the IV will be a set/known size based on the algorithm. NOTE: the AES algorithm will output the same result if using the same IV, key and message. It is recommended that the IV be randomly created each time an encryption takes place.
With the newly initialized Cipher, encrypting a message is simple. Simply call:
Byte arrays are difficult to visualize since they often do not form characters in any charset. The best recommendation to solve this is to represent the bytes in HEX (base-16), Double HEX (base-32) or Base64 format. If the message will be passed via a URL or POST parameter, be sure to use a web-safe Base64 encoding. Google Guava library provides a excellent BaseEncoding utility. NOTE: Remember to decode the encoded message before decrypting.
Decrypting a message is almost a reverse of the encryption process with a few exceptions. Decryption requires a known initialization vector as a parameter unlike the encryption process generating a random IV.
When decrypting, obtain a cipher object with the same process as the encryption method. The Cipher object will need to utilize the exact same algorithm including the method and padding selections. Once the code has obtained a reference to a Cipher object, the next step is to initialize the cipher for decryption and pass in a reference to a key and the initialization vector.NOTE: The key is stored in the keystore and obtained by the use of an alias. See below for details on obtaining keys from a keystore
Once the cipher has been provided the key, IV and initialized for decryption, the cipher is ready to perform the decryption.
The IV used to encrypt the message is important to decrypting the message therefore the question is raised, how do they stay together. One solution is to Base Encode (see above) the IV and prepend it to the encrypted and encoded message: Base64UrlSafe(myIv) + delimiter + Base64UrlSafe(encryptedMessage). Other possible solutions might be contextual such as including an attribute in an XML file with the IV and one for the alias to the key used.
The beginning of this post has shown how easy it is to create new AES-256 keys that reference an alias inside of a keystore database. The post then continues on how to encrypt and decrypt a message given a key, but has yet shown how to obtain a reference to the key in a keystore.
This post has shown how to encrypt and decrypt string based messages using the AES-256 encryption algorithm. The keys to encrypt and decrypt these messages are held inside of a JCEKS formatted KeyStore database created using the JDK provided 'keytool' utility. The examples in this post should be considered a solid start to encrypting/decrypting symmetric keys such as AES. This should not be considered the only line of defense when encrypting messages, for example key rotation. Key rotation is a method to mitigate risks in the event of a data breach. If an intruder obtains data and manages to hack a single key, the data contained in multiple files should have used several keys to encrypt the data thus bringing down risk of a total exposure loss.
All of the examples in this blog post have been condensed into a simple tool allowing for the viewing of keys inside of a keystore, an operation that is not supported out of the box by the JDK keytool. Each aspect of the steps and topics outlined in this post are available at: https://github.com/mike-ensor/aes-256-encryption-utility. NOTE: The examples, sample code and any reference is to be used at the sole implementers risk and there is no implied warranty or liability, you assume all risks.
Advanced Encryption Standard(AES) is a symmetric encryption algorithm. AES is the industry standard as of now as it allows 128 bit, 192 bit and 256 bit encryption.Symmetric encryption is very fast as compared to asymmetric encryption and are used in systems such as database system. Following is an online tool to generate AES encrypted password and decrypt AES encrypted password. It provides two mode of encryption and decryption ECB and CBC mode. For more info on AES encryption visit this explanation on AES Encryption.
Also, you can find the sample usage screenshot below:
Any plain-text input or output that you enter or we generate is not stored on this site, this tool is provided via an HTTPS URL to ensure that text cannot be stolen.
For encryption, you can either enter the plain text, password, an image file or a .txt file that you want to encrypt. Now choose the block cipher mode of encryption. ECB(Electronic Code Book) is the simplest encryption mode and does not require IV for encryption. The input plain text will be divided into blocks and each block will be encrypted with the key provided and hence identical plain text blocks are encrypted into identical cipher text blocks. CBC mode is highly recommended and it requires IV to make each message unique. If no IV is entered then default will be used here for CBC mode and that defaults to a zero based byte[16].
The AES algorithm has a 128-bit block size, regardless of whether you key length is 256, 192 or 128 bits. When a symmetric cipher mode requires an IV, the length of the IV must be equal to the block size of the cipher. Hence, you must always use an IV of 128 bits (16 bytes) with AES.
AES provides 128 bit, 192 bit and 256 bit of secret key size for encryption. Things to remember here is if you are selecting 128 bits for encryption, then the secret key must be of 16 bits long and 24 and 32 bits for 192 and 256 bits of key size. Now you can enter the secret key accordingly. By default, the encrypted text will be base64 encoded but you have options to select the output format as HEX too.
Similarly, for image and .txt file the encrypted form will be Base64 encoded. Rsa public key example.
Below is a screenshot that shows a sample usage of this online AES encryption tool.
AES decryption has also the same process. By default it assumes the entered text be in Base64. The input can be Base64 encoded or Hex encoded image and .txt file too. And the final decrypted output will be Base64 string. If the intended output is a plain-text then, it can be decoded to plain-text in-place.
But if the intended output is an image or .txt file then you can use this tool to convert the base64 encoded output to an image.
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