Adding scalrmult_ native impl, starting work on sample

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Ugljesa Jovanovic 2020-10-15 20:38:30 +02:00
parent 60dfdb01cc
commit c66fde8502
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7 changed files with 98 additions and 24 deletions

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@ -0,0 +1,34 @@
package com.ionspin.kotlin.crypto.scalarmut
/**
* Created by Ugljesa Jovanovic
* ugljesa.jovanovic@ionspin.com
* on 15-Oct-2020
*/
const val crypto_scalarmult_BYTES = 32
const val crypto_scalarmult_SCALARBYTES = 32
expect object ScalarMultiplication {
/**
* This function can be used to compute a shared secret q given a user's secret key and another user's public key.
* n is crypto_scalarmult_SCALARBYTES bytes long, p and the output are crypto_scalarmult_BYTES bytes long.
* q represents the X coordinate of a point on the curve. As a result, the number of possible keys is limited to
* the group size (2^252), which is smaller than the key space.
* For this reason, and to mitigate subtle attacks due to the fact many (p, n) pairs produce the same result,
* using the output of the multiplication q directly as a shared key is not recommended.
* A better way to compute a shared key is h(q pk1 pk2), with pk1 and pk2 being the public keys.
* By doing so, each party can prove what exact public key they intended to perform a key exchange with
* (for a given public key, 11 other public keys producing the same shared secret can be trivially computed).
* This can be achieved with the following code snippet:
*/
fun scalarMultiplication(secretKeyN : UByteArray, publicKeyP: UByteArray) : UByteArray
/**
* Given a user's secret key n (crypto_scalarmult_SCALARBYTES bytes), the crypto_scalarmult_base() function
* computes the user's public key and puts it into q (crypto_scalarmult_BYTES bytes).
* crypto_scalarmult_BYTES and crypto_scalarmult_SCALARBYTES are provided for consistency,
* but it is safe to assume that crypto_scalarmult_BYTES == crypto_scalarmult_SCALARBYTES.
*/
fun scalarMultiplicationBase(secretKeyN : UByteArray) : UByteArray
}

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@ -0,0 +1,58 @@
package com.ionspin.kotlin.crypto.scalarmut
import com.ionspin.kotlin.crypto.util.toPtr
import kotlinx.cinterop.pin
import libsodium.crypto_scalarmult
import libsodium.crypto_scalarmult_base
actual object ScalarMultiplication {
/**
* This function can be used to compute a shared secret q given a user's secret key and another user's public key.
* n is crypto_scalarmult_SCALARBYTES bytes long, p and the output are crypto_scalarmult_BYTES bytes long.
* q represents the X coordinate of a point on the curve. As a result, the number of possible keys is limited to
* the group size (2^252), which is smaller than the key space.
* For this reason, and to mitigate subtle attacks due to the fact many (p, n) pairs produce the same result,
* using the output of the multiplication q directly as a shared key is not recommended.
* A better way to compute a shared key is h(q pk1 pk2), with pk1 and pk2 being the public keys.
* By doing so, each party can prove what exact public key they intended to perform a key exchange with
* (for a given public key, 11 other public keys producing the same shared secret can be trivially computed).
* This can be achieved with the following code snippet:
*/
actual fun scalarMultiplication(secretKeyN: UByteArray, publicKeyP: UByteArray): UByteArray {
val result = UByteArray(crypto_scalarmult_BYTES)
val resultPinned = result.pin()
val secretKeyNPinned = secretKeyN.pin()
val publicKeyPPinned = publicKeyP.pin()
crypto_scalarmult(resultPinned.toPtr(), secretKeyNPinned.toPtr(), publicKeyPPinned.toPtr())
resultPinned.unpin()
secretKeyNPinned.unpin()
publicKeyPPinned.unpin()
return result
}
/**
* Given a user's secret key n (crypto_scalarmult_SCALARBYTES bytes), the crypto_scalarmult_base() function
* computes the user's public key and puts it into q (crypto_scalarmult_BYTES bytes).
* crypto_scalarmult_BYTES and crypto_scalarmult_SCALARBYTES are provided for consistency,
* but it is safe to assume that crypto_scalarmult_BYTES == crypto_scalarmult_SCALARBYTES.
*/
actual fun scalarMultiplicationBase(
secretKeyN: UByteArray
): UByteArray {
val result = UByteArray(crypto_scalarmult_BYTES)
val resultPinned = result.pin()
val secretKeyNPinned = secretKeyN.pin()
crypto_scalarmult_base(resultPinned.toPtr(), secretKeyNPinned.toPtr())
resultPinned.unpin()
secretKeyNPinned.unpin()
return result
}
}

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@ -144,7 +144,7 @@ kotlin {
implementation(kotlin(Deps.Common.stdLib))
implementation(kotlin(Deps.Common.test))
implementation(Deps.Common.kotlinBigNum)
implementation(project(":multiplatform-crypto-delegated"))
implementation(project(":multiplatform-crypto-libsodium-bindings"))
}
}
val commonTest by getting {

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@ -1,28 +1,12 @@
package com.ionspin.kotlin.crypto.sample
import com.ionspin.kotlin.crypto.Crypto
import com.ionspin.kotlin.crypto.CryptoInitializerDelegated
import com.ionspin.kotlin.crypto.CryptoPrimitives
import com.ionspin.kotlin.crypto.hash.encodeToUByteArray
import com.ionspin.kotlin.crypto.util.LibsodiumRandom
import com.ionspin.kotlin.crypto.util.toHexString
object Sample {
fun runSample() {
println("Initializing crypto library")
CryptoInitializerDelegated.initializeWithCallback {
blake2b()
}
}
fun blake2b() {
println("Blake2b updateable")
val blake2bUpdateable = CryptoPrimitives.Blake2b.updateable()
blake2bUpdateable.update("test".encodeToUByteArray())
println(blake2bUpdateable.digest().toHexString())
println("Blake2b stateless")
val statelessResult = CryptoPrimitives.Blake2b.stateless("test".encodeToUByteArray())
println("Blake2b stateless: ${statelessResult.toHexString()}")
val random = LibsodiumRandom.buf(32)
println("Random: ${random.toHexString()}")
}
}

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@ -2,7 +2,6 @@ import com.ionspin.kotlin.crypto.sample.Sample
import kotlin.time.ExperimentalTime
@ExperimentalTime
fun main() {
Sample.runSample()

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@ -1,7 +1,5 @@
import com.ionspin.kotlin.crypto.sample.Sample
fun main() {
Sample.runSample()
}

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@ -156,6 +156,7 @@ native libsodium library.
## Constants
| Constant name| Implemented |
|-------------|-------------|
| SODIUM_LIBRARY_VERSION_MAJOR | |
| SODIUM_LIBRARY_VERSION_MINOR | |
| crypto_aead_chacha20poly1305_ABYTES | |