Secure. Portable. Pure Kotlin.

Kodium is a comprehensive, pure Kotlin Multiplatform (KMP) cryptography library. It acts as a faithful port of the renowned TweetNaCl C library, providing high-speed, high-security cryptographic primitives without any native dependencies.

Write once, encrypt everywhere.

• Pure Kotlin: No JNI, no C interop headaches, no complex build scripts for native binaries. Just pure Kotlin code running everywhere.
• TweetNaCl Core: Built on the solid foundation of the TweetNaCl crypto suite, known for its security and simplicity.
• Multiplatform Native: First-class support for Android, iOS, JVM, JavaScript (Browser/Node), Wasm, Linux, macOS, and Windows.
• Developer Friendly: Simple, opinionated APIs for common tasks (Box, SecretBox, Signatures).

• Initial implementation of the library.
• Port of TweetNaCl (Box, SecretBox, Signatures).
• Base58Check encoding/decoding.
• Minimal test coverage.

Add Kodium to your common module's dependencies.

Gradle (Kotlin DSL)

implementation("eu.livotov.labs:kodium:0.0.1")

Gradle (Groovy)

implementation 'eu.livotov.labs:kodium:0.0.1'

Maven

<dependency>
    <groupId>eu.livotov.labs</groupId>
    <artifactId>kodium</artifactId>
    <version>0.0.1</version>
</dependency>

• Public-Key Cryptography (Box): Authenticated encryption using Curve25519, XSalsa20, and Poly1305.
• Secret-Key Cryptography (SecretBox): Authenticated encryption using XSalsa20 and Poly1305.
• Digital Signatures: Ed25519 high-speed, high-security signatures.
• Key Management: Secure generation, import, and export of keys (Raw & Base58Check).
• Utils: Robust Base58Check encoding/decoding.

Securely exchange messages between Alice and Bob.

// 1. Generate keys
val alice = Kodium.generateKeyPair()
val bob = Kodium.generateKeyPair()

// 2. Alice encrypts a message for Bob
val message = "The eagle flies at midnight.".encodeToByteArray()

val encryptedResult = Kodium.encryptToEncodedString(
    mySecretKey = alice,
    theirPublicKey = bob.getPublicKey(),
    data = message
)

// 3. Bob decrypts the message
encryptedResult.onSuccess { cipherText ->
    Kodium.decryptFromEncodedString(
        mySecretKey = bob,
        theirPublicKey = alice.getPublicKey(),
        data = cipherText
    ).onSuccess { decryptedBytes ->
        println("Decrypted: ${decryptedBytes.decodeToString()}")
    }
}

Protect data with a shared password/secret.

val password = "CorrectHorseBatteryStaple"
val secretData = "Launch codes: 12345".encodeToByteArray()

// Encrypt
val encryptedResult = Kodium.encryptSymmetricToEncodedString(password, secretData)

// Decrypt
encryptedResult.onSuccess { cipherText ->
    val decryptedResult = Kodium.decryptSymmetricFromEncodedString(password, cipherText)
    println("Restored: ${decryptedResult.getOrThrow().decodeToString()}")
}

Easily store keys using Base58Check encoding.

val keyPair = Kodium.generateKeyPair()

// Export Public Key (Safe to share)
val pubKeyString = keyPair.getPublicKey().exportToEncodedString()

// Export Private Key (Encrypted with a password)
val privKeyString = keyPair.exportToEncryptedString("StrongPassword")

// Import later
val restoredKeyPair = KodiumPrivateKey.importFromEncryptedString(
    data = privKeyString.getOrThrow(), 
    password = "StrongPassword"
)

Kodium provides efficient Base58 and Base58Check extensions for ByteArray and String. Base58 is superior to Base64 for many crypto use cases as it eliminates ambiguous characters (0OIl) and is more compact than hexadecimal.

val data = "Kodium Pure Kotlin".encodeToByteArray()

// Standard Base58
val b58 = data.encodeToBase58String()
val decoded = b58.decodeBase58()

// Base58 with Checksum (Standard in Bitcoin/Crypto)
val b58Check = data.encodeToBase58WithChecksum()
val decodedCheck = b58Check.decodeBase58WithChecksum()

Derive strong cryptographic keys from user passwords using PBKDF2 with HMAC-SHA256.

val password = "UserPassword123".encodeToByteArray()
val salt = "RandomSalt".encodeToByteArray() // Should be random and at least 16 bytes

// Derive a 32-byte key
val derivedKey = KDF.deriveKey(
    password = password,
    salt = salt,
    iterations = 100_000,
    keyLengthBytes = 32
)

Kodium is licensed under the Apache 2.0 License.

Copyright 2026 Livotov Labs Ltd.

Disclaimer: While this library implements standard cryptographic primitives based on TweetNaCl, it has not been audited by a security expert. Users should always review security requirements for their specific use case and use at their own risk.