ECC-25519

This project helps to use elliptic curve cryptography (ECC) with Curve25519 by Daniel J Bernstein. It combines multiple libraries.

All credit goes to following libraries. Please respect their licenses!

Android:

• https://github.com/dazoe/Android.Ed25519
• https://code.google.com/p/curve25519-java/

Java:

• https://github.com/str4d/ed25519-java/
• https://code.google.com/p/curve25519-java/

Download

Download the latest version or grab via Gradle:

dependencies {
    compile 'net.vrallev.ecc:ecc-25519-android:1.0.3' 	// Android
    compile 'net.vrallev.ecc:ecc-25519-java:1.0.3' 		// JVM
}

Usage

byte[] seed = "My random seed".getBytes();
byte[] privateKey = KeyHolder.createPrivateKey(seed); // creates a valid private key (seed hashed with SHA-256) 

KeyHolder keyHolder = new KeyHolder(privateKey); // computes valid public keys
Ecc25519Helper helper = new Ecc25519Helper(keyHolder); // generate our helper class 

byte[] sharedSecret = helper.diffieHellman(); // you can also pass a private and public key

byte[] message = "My message".getBytes();
byte[] signature = helper.sign(message); // computes the signature with the private key
boolean validSignature = helper.isValidSignature(message, signature); // checks the message with the public key from keyHolder instance

License

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

   http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.