Cryptography

This repository will slowly get more and more cryptography code samples written in Java. Methods are related to Cryptography android application cipher method collection. Point of this repository is that users can find everything in one place, modify code, play with these methods in any way they want and this way learn how ciphers worked in the past and how they work these days. In short words this repository is meant to be educational.

This repository is part of this Android application: Google Play - Cryptography

Feel free to contribute or open issues!

Table of contents

• Ciphers
• Converters
• Encoding
• Hashes
• Random
• Certificates
• Signatures
• Installation
• Running tests
  • Automatically
  • Manually
• External libraries
• Adding external library
• Notes
• Troubleshooting
• Contributions
• Authors
• Contributors
• License

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Ciphers

Cipher (or cypher) is an algorithm for performing encryption or decryption—a series of well-defined steps that can be followed as a procedure. Encryption is the process of encoding information. This process converts the original representation of the information, known as plaintext, into an alternative form known as ciphertext.

Adfgvx

AES - 128 / 192 / 256

Anubis - 320

ARIA

Atbash

Autokey

Bacon

Beaufort

Blowfish

Caesar

CAST - 5 / 6

Chaocipher

Elgamal

Gronsfeld

IDEA

Keyword

Khazad - 128

LC4 / LS47

Navajo

OneTimePad | Vernam

Playfair

Porta

Rail fence

RC - 2 / 4 / 6

Scytale

Vigenere

Elliptic Curve

VIC

Converters

Converters converts input from representation system A to representation system B and vice versa.

BinaryDecimal

BinaryHex

BinaryInteger

BinaryText

Compliment

Encoding

Encoding is used to represent data in ASCII string format by translating the data into selected encoding representation.

A1z26

Adaptive Huffman

Base16

Base32

Base58

Base64

Base85

Base91

Huffman

Morse

PEM

Pig Latin

RLE

Koblitz

VIC Sequencing

Hashes

A hash function is any function that can be used to map data of arbitrary size to fixed-size values. The values returned by a hash function are called hash values, hash codes, digests, or simply hashes.

ADLER - 32

Blake2b - 160 / 256 / 384 / 512

CRC - 8 / 16 / 24 / 32 / 64

ELF - 32

FCS - 16

HAS - 160

KECCAK - 256 / 384 / 512

Kupyna - 256 / 384 / 512

MD - 2 / 4 / 5

PBKDF2

RIPEMD - 128 / 160 / 256 / 320

SHA - 0 / 1 / 224 / 256 / 384 / 512

SHA2 - 224 / 256 / 384 / 512

SHA3 - 224 / 256 / 384 / 512

Skein - 256 / 512 / 1024

SM3

SUM - 8 / 16 / 24 / 32

TIGER - T / 2 / 128 / 160

WHIRLPOOL - 0 / 1 / W

XOR - 8

Random

Random generation is a process which, often by means of a random number generator (RNG), generates a sequence of numbers or symbols that cannot be reasonably predicted better than by a random chance.

Dummy - Bytes

Secure Random - Strong / SHA1PRNG

Certificates

In computer security, an attribute certificate, or authorization certificate (AC) is a digital document containing attributes associated to the holder by the issuer. When the associated attributes are mainly used for the purpose of authorization, AC is called authorization certificate. AC is standardized in X.509. RFC 5755 further specifies the usage for authorization purpose in the Internet.

X509

Signatures

mathematical scheme for verifying the authenticity of digital messages or documents. A valid digital signature, where the prerequisites are satisfied, gives a recipient very strong reason to believe that the message was created by a known sender (authentication), and that the message was not altered in transit (integrity).

JWT - Json Web Token

Installation

1. Download and install eclipse: https://www.eclipse.org/downloads/ or any other IDE.
2. Download project source code by either cloning it with Git or by Clone or download menu Download ZIP option.
3. Open project in Eclipse File - Open projects from File System...
4. Navigate to /src - cryptography - Ciphers.java and start play with it. Rest of the folder structure has method specific code and tests files for running automated tests.

I warmly recommend watching basic Eclipse tutorials if you are new to the topic.

Running tests

Automatically

1. Make new branch.
2. Push changes. (tests will be run with each push)
3. Open pull request.
4. Later tests are run by Github Actions workflow (./.github/workflows/Tests.yml).

Manually

1. Right click on TestRunner.java
2. Click Coverage As
3. Select 1 Java Application
4. If everything is fine result is Tests success: true

External libraries

commons-codec-1.10.jar

• Included for Base32 and Base64 encoding methods.

jacksum-1.7.0 (jacksum.jar)

• Included for many hashing algorithms.
• You can find all source code and details here: https://jacksum.loefflmann.net/en/download.html

core-1.58.0.0.jar | prov-1.58.0.0.jar | bcpg-jdk15on-1.58.0.0.jar | bcpkix-jdk15on-1.58.0.0.jar (Spongy Castle)

• Providing tons of newer strong Cryptographic methods. See https://rtyley.github.io/spongycastle/ and http://www.bouncycastle.org/java.html

bcprov-jdk15on-170

• BouncyCastle signed cryptography provider

bcpkix-jdk15on-170

• BouncyCastle signed cryptography provider

org.junit_4.13.0.v20200204-1500.jar | core-1.3.0.jar

• JUnit 4 jar and hamcrest core for Github Actions based test runs.

Adding external library

Every time new external jar library is added, it must be also added to build.xml in a block seen below as example

<path id="Cryptography.classpath">
    <pathelement location="bin"/>
    <path refid="JUnit 4.libraryclasspath"/>
    <pathelement location="jar/commons-codec-1.10.jar"/>
    <pathelement location="jar/jacksum.jar"/>
    <pathelement location="jar/core-1.58.0.0.jar"/>
    <pathelement location="jar/prov-1.58.0.0.jar"/>
    <pathelement location="jar/bcpkix-jdk15on-1.58.0.0.jar"/>
    <pathelement location="jar/bcpg-jdk15on-1.58.0.0.jar"/>
    <pathelement location="jar/org.junit_4.13.0.v20200204-1500.jar"/>
    <pathelement location="jar/core-1.3.0.jar"/>
    <pathelement location="jar/bcprov-jdk15on-170"/>
    <pathelement location="jar/bcpkix-jdk15on-170"/>
</path>

Notes

Some ciphers or parts of ciphers originate from web sites, tutorials, repositories or other sources. There's unfortunately no links to original references.

Troubleshooting

Noticed at Mac with jdk1.8.0...

[java.security.InvalidKeyException: Illegal key size or default parameters]>

this could be due to crypto policy being limited at java config. To change this, go to:

cd /Library/Java/JavaVirtualMachines/jdk1.8.0_152.jdk/Contents/Home/jre/lib/security/
sudo nano java.security

and uncomment out crypto.policy=unlimited:

Following did same trick but from code, so used this one:

import java.security.Security;
public class SomeClass {
	public static void main(String[] args) {
        Security.setProperty("crypto.policy", "unlimited");
    }
}

Contributions

Rules?

• Please, write tests if you make something new.

Found problem?

• Open issue or make new branch and create pull request when problem is fixed.

Want to optimize code?

• You are free to optimize code, make new branch and create pull request when ready.

Authors

• Norkator - Initial work - norkator

Contributors

• Saurav Kumar - *Added Morse, Huffman, Compliment, Koblitz, EllipticCurve, VICsequencing, VIC * - SKR301

License

See repo license section or license file.