https://github.com/andreypfau/curve25519-kotlin

A pure Kotlin/Multiplatform implementation of group operations on Curve25519.
https://github.com/andreypfau/curve25519-kotlin

cryptography curve25519 ed25519 edwards-curve kotlin kotlin-js kotlin-jvm kotlin-multiplatform kotlin-native montgomery-curve x25519

Last synced: 8 months ago
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A pure Kotlin/Multiplatform implementation of group operations on Curve25519.

• Host: GitHub
• URL: https://github.com/andreypfau/curve25519-kotlin
• Owner: andreypfau
• License: mit
• Created: 2022-10-22T01:22:32.000Z (about 3 years ago)
• Default Branch: main
• Last Pushed: 2025-01-14T01:48:07.000Z (11 months ago)
• Last Synced: 2025-03-30T04:51:15.168Z (9 months ago)
• Topics: cryptography, curve25519, ed25519, edwards-curve, kotlin, kotlin-js, kotlin-jvm, kotlin-multiplatform, kotlin-native, montgomery-curve, x25519
• Language: Kotlin
• Homepage:
• Size: 1.06 MB
• Stars: 19
• Watchers: 2
• Forks: 2
• Open Issues: 0
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

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README

          
# curve25519-kotlin

[![Maven Central](https://img.shields.io/maven-central/v/io.github.andreypfau/curve25519-kotlin.svg)](https://search.maven.org/artifact/io.github.andreypfau/curve25519-kotlin/0.0.8/pom)

[![License](https://img.shields.io/badge/License-MIT-blue.svg)](https://opensource.org/licenses/MIT)

[![Kotlin](https://img.shields.io/badge/kotlin-1.7.20-blue.svg?logo=kotlin)](http://kotlinlang.org)

**A pure Kotlin/Multiplatform implementation of group operations on Curve25519.**

### Gradle Kotlin DSL:

```kotlin

dependencies {

    implementation("io.github.andreypfau:curve25519-kotlin:0.0.8")

}

```

### Apache Maven:

```xml

    io.github.andreypfau

    curve25519-kotlin-jvm

    0.0.8

```

## Examples:

### Generate key-pair from random

```kotlin

val privateKey: Ed25519PrivateKey = Ed25519.generateKey(Random)

val publicKey: Ed25519PublicKey = privateKey.publicKey()

```

### Generate key-pair from seed bytes

```kotlin

val seedBytes: ByteArray = ByteArray(32)

val privateKey: Ed25519PrivateKey = Ed25519.keyFromSeed(seedBytes)

val publicKey: Ed25519PublicKey = privateKey.publicKey() 

```

### Signing messages & verify signatures

```kotlin

val message: ByteArray = "test message".encodeToByteArray()

val signature: ByteArray = privateKey.sign(message)

check(publicKey.verify(message, signature)) // Valid message returns true

val invalidMessage = "invalid message".encodeToByteArray()

check(!publicKey.verify(invalidMessage, signature)) // Invalid message returns false

```

### Shared key calculation

```kotlin

val alicePrivate = Ed25519.generateKey(Random)

val alicePublic = alicePrivate.publicKey()

val bobPrivate = Ed25519.generateKey(Random)

val bobPublic = bobPrivate.publicKey()

val aliceShared = alicePrivate.sharedKey(bobPublic)

val bobShared = bobPrivate.sharedKey(alicePublic)

check(aliceShared.contentEquals(bobShared))

```