diff --git a/build.sbt b/build.sbt
index 4a54b68..77b9139 100644
--- a/build.sbt
+++ b/build.sbt
@@ -33,11 +33,12 @@ val Deps = new {
   }
 
   val Gs = new {
-    val Datagen: ModuleID = "gs" %% "gs-datagen-core-v0" % "0.1.1"
+    val Datagen: ModuleID = "gs" %% "gs-datagen-core-v0" % "0.4.1"
   }
 
   val BouncyCastle = new {
     val Provider: ModuleID = "org.bouncycastle" % "bcprov-jdk18on" % "1.83"
+    val PKIX: ModuleID     = "org.bouncycastle" % "bcpkix-jdk18on" % "1.83"
   }
 
   val MUnit: ModuleID = "org.scalameta" %% "munit" % "1.2.2"
@@ -65,7 +66,8 @@ lazy val core = project
   )
   .settings(
     libraryDependencies ++= Seq(
-      Deps.Cats.Effect
+      Deps.Cats.Effect,
+      Deps.BouncyCastle.PKIX
     )
   )
 
diff --git a/modules/core/src/main/scala/gs/crypto/v0/BaseKeyLoader.scala b/modules/core/src/main/scala/gs/crypto/v0/BaseKeyLoader.scala
index 52e1873..f8a8afa 100644
--- a/modules/core/src/main/scala/gs/crypto/v0/BaseKeyLoader.scala
+++ b/modules/core/src/main/scala/gs/crypto/v0/BaseKeyLoader.scala
@@ -1,12 +1,39 @@
 package gs.crypto.v0
 
+import cats.effect.Sync
+import cats.syntax.all.*
+import java.security.PrivateKey
+import java.security.PublicKey
+
 /** Base implementation for [[KeyLoader]] that provides standard parsing
   * functionality.
   */
-abstract class BaseKeyLoader[F[_]] extends KeyLoader[F]:
-  /** @return
-    *   The key loader configuration.
-    */
+abstract class BaseKeyLoader[F[_]: Sync] extends KeyLoader[F]:
+
+  def loadPublicKey(
+    location: String,
+    algorithm: String
+  ): F[Either[KeyLoadError, PublicKey]] =
+    loadKey(location).flatMap {
+      case Left(err) => Sync[F].pure(Left(err))
+      case Right(key) =>
+        KeyLoader.loadPublicKey[F](key, algorithm).map(Right(_))
+    }
+
+  def loadPrivateKey(
+    location: String,
+    algorithm: String
+  ): F[Either[KeyLoadError, PrivateKey]] =
+    loadKey(location).flatMap {
+      case Left(err) => Sync[F].pure(Left(err))
+      case Right(key) =>
+        KeyLoader.loadPrivateKey[F](key, algorithm).map(Right(_))
+    }
+
+    /** @return
+      *   The key loader configuration.
+      */
+
   def config: BaseKeyLoader.Config
 
   protected def prepareKey(base: String): Either[KeyLoadError, Array[Byte]] =
diff --git a/modules/core/src/main/scala/gs/crypto/v0/FileKeyLoader.scala b/modules/core/src/main/scala/gs/crypto/v0/FileKeyLoader.scala
index 54b0874..22d27fa 100644
--- a/modules/core/src/main/scala/gs/crypto/v0/FileKeyLoader.scala
+++ b/modules/core/src/main/scala/gs/crypto/v0/FileKeyLoader.scala
@@ -2,7 +2,6 @@ package gs.crypto.v0
 
 import cats.effect.Sync
 import cats.syntax.all.*
-import java.nio.charset.Charset
 import java.nio.file.Files
 import java.nio.file.Path
 
@@ -14,8 +13,7 @@ import java.nio.file.Path
   *   The expected character set for the loaded file.
   */
 class FileKeyLoader[F[_]: Sync](
-  val config: BaseKeyLoader.Config,
-  val charset: Charset
+  val config: BaseKeyLoader.Config
 ) extends BaseKeyLoader[F]:
 
   /** @inheritDocs
@@ -28,5 +26,5 @@ class FileKeyLoader[F[_]: Sync](
       case false =>
         Sync[F].pure(Left(KeyLoadError.PathNotRegularFile(p, location)))
       case true =>
-        Sync[F].delay(Files.readString(p, charset)).map(prepareKey)
+        Sync[F].delay(Files.readString(p)).map(prepareKey)
     }
diff --git a/modules/core/src/main/scala/gs/crypto/v0/KeyLoader.scala b/modules/core/src/main/scala/gs/crypto/v0/KeyLoader.scala
index 65f5027..c0b8aba 100644
--- a/modules/core/src/main/scala/gs/crypto/v0/KeyLoader.scala
+++ b/modules/core/src/main/scala/gs/crypto/v0/KeyLoader.scala
@@ -1,38 +1,61 @@
 package gs.crypto.v0
 
-import cats.Applicative
 import cats.effect.Sync
-import java.nio.charset.Charset
-import java.nio.charset.StandardCharsets
+import java.security.KeyFactory
+import java.security.PrivateKey
+import java.security.PublicKey
+import java.security.spec.PKCS8EncodedKeySpec
+import java.security.spec.X509EncodedKeySpec
 
 /** Interface for loading keys (e.g. public/private keys) into memory.
   */
 trait KeyLoader[F[_]]:
-  /** Load the key from the given location.
+  /** Load the key from the given location. This gets the raw bytes, but does
+    * not handle _any_ standard encodings such as PKCS8 or X509. These are
+    * handled by helper functions (static) or [[BaseKeyLoader]].
     *
     * @param location
     *   The location of the key.
     * @return
-    *   The loaded key.
+    *   The key's raw bytes - ready for further decoding.
     */
   def loadKey(location: String): F[Either[KeyLoadError, Array[Byte]]]
 
 object KeyLoader:
 
-  def stringLoader[F[_]: Applicative](
-    config: BaseKeyLoader.Config
+  def stringLoader[F[_]: Sync](
+    config: BaseKeyLoader.Config = BaseKeyLoader.Defaults.Config
   ): StringKeyLoader[F] =
-    new StringKeyLoader[F](config)
+    new StringKeyLoader(config)
 
   def fileLoader[F[_]: Sync](
-    config: BaseKeyLoader.Config,
-    charset: Charset = StandardCharsets.UTF_8
+    config: BaseKeyLoader.Config = BaseKeyLoader.Defaults.Config
   ): FileKeyLoader[F] =
-    new FileKeyLoader(config, charset)
+    new FileKeyLoader(config)
 
   def resourceLoader[F[_]: Sync](
-    config: BaseKeyLoader.Config
+    config: BaseKeyLoader.Config = BaseKeyLoader.Defaults.Config
   ): ResourceKeyLoader[F] =
     new ResourceKeyLoader(config)
 
+  def loadPublicKey[F[_]: Sync](
+    publicKeyRawBytes: Array[Byte],
+    algorithm: String
+  ): F[PublicKey] =
+    Sync[F].delay {
+      val spec       = new X509EncodedKeySpec(publicKeyRawBytes)
+      val keyFactory = KeyFactory.getInstance(algorithm)
+      keyFactory.generatePublic(spec)
+    }
+
+  def loadPrivateKey[F[_]: Sync](
+    privateKeyRawBytes: Array[Byte],
+    algorithm: String
+  ): F[PrivateKey] =
+    Sync[F].delay {
+      val spec       = new PKCS8EncodedKeySpec(privateKeyRawBytes)
+      val keyFactory = KeyFactory.getInstance(algorithm)
+      keyFactory.generatePrivate(spec)
+    }
+
 end KeyLoader
diff --git a/modules/core/src/main/scala/gs/crypto/v0/SignatureVerifier.scala b/modules/core/src/main/scala/gs/crypto/v0/SignatureVerifier.scala
index 713ee32..5a497ee 100644
--- a/modules/core/src/main/scala/gs/crypto/v0/SignatureVerifier.scala
+++ b/modules/core/src/main/scala/gs/crypto/v0/SignatureVerifier.scala
@@ -3,4 +3,8 @@ package gs.crypto.v0
 /** Used to verify cryptographic signatures.
   */
 trait SignatureVerifier[F[_]]:
-  def verify(signature: Signature): F[SignatureValidity]
+
+  def verify(
+    signature: Signature,
+    data: Array[Byte]
+  ): F[SignatureValidity]
diff --git a/modules/core/src/main/scala/gs/crypto/v0/StringKeyLoader.scala b/modules/core/src/main/scala/gs/crypto/v0/StringKeyLoader.scala
index eb458c7..46cbc2a 100644
--- a/modules/core/src/main/scala/gs/crypto/v0/StringKeyLoader.scala
+++ b/modules/core/src/main/scala/gs/crypto/v0/StringKeyLoader.scala
@@ -1,19 +1,15 @@
 package gs.crypto.v0
 
-import cats.Applicative
+import cats.effect.Sync
 
 /** Implementation of [[KeyLoader]] that loads keys directly from input strings.
   *
   * @param config
   *   The key loader configuration.
   */
-class StringKeyLoader[F[_]: Applicative](
+class StringKeyLoader[F[_]: Sync](
   val config: BaseKeyLoader.Config
 ) extends BaseKeyLoader[F]:
 
-  /** @inheritDocs
-    */
-  override def loadKey(
-    location: String
-  ): F[Either[KeyLoadError, Array[Byte]]] =
-    Applicative[F].pure(prepareKey(location))
+  override def loadKey(location: String): F[Either[KeyLoadError, Array[Byte]]] =
+    Sync[F].delay(prepareKey(location))
diff --git a/modules/eddsa/src/main/scala/gs/crypto/v0/eddsa/Ed25519.scala b/modules/eddsa/src/main/scala/gs/crypto/v0/eddsa/Ed25519.scala
new file mode 100644
index 0000000..6ea343c
--- /dev/null
+++ b/modules/eddsa/src/main/scala/gs/crypto/v0/eddsa/Ed25519.scala
@@ -0,0 +1,7 @@
+package gs.crypto.v0.eddsa
+
+object Ed25519:
+
+  val Algorithm: String = "Ed25519"
+
+end Ed25519
diff --git a/modules/eddsa/src/main/scala/gs/crypto/v0/eddsa/Ed25519Signer.scala b/modules/eddsa/src/main/scala/gs/crypto/v0/eddsa/Ed25519Signer.scala
index b10cfbe..7ae148b 100644
--- a/modules/eddsa/src/main/scala/gs/crypto/v0/eddsa/Ed25519Signer.scala
+++ b/modules/eddsa/src/main/scala/gs/crypto/v0/eddsa/Ed25519Signer.scala
@@ -5,7 +5,7 @@ import gs.crypto.v0.Signature
 import gs.crypto.v0.Signer
 import java.nio.charset.Charset
 import java.nio.charset.StandardCharsets
-import org.bouncycastle.crypto.params.Ed25519PrivateKeyParameters
+import java.security.PrivateKey
 
 /** Implementation of [[Signer]] that uses the Ed25519 system to calculate
   * signatures.
@@ -16,18 +16,17 @@ import org.bouncycastle.crypto.params.Ed25519PrivateKeyParameters
   *   The private key.
   */
 final class Ed25519Signer[F[_]: Sync](
-  privateKey: Array[Byte]
+  privateKey: PrivateKey
 ) extends Signer[F]:
-  private lazy val params = new Ed25519PrivateKeyParameters(privateKey)
 
   /** @inheritDocs
     */
   override def sign(data: Array[Byte]): F[Signature] =
     Sync[F].delay {
-      val s = new org.bouncycastle.crypto.signers.Ed25519Signer()
-      val _ = s.init(true, params)
-      val _ = s.update(data, 0, data.length)
-      Signature(s.generateSignature())
+      val s = java.security.Signature.getInstance(Ed25519.Algorithm)
+      val _ = s.initSign(privateKey)
+      val _ = s.update(data)
+      Signature(s.sign())
     }
 
   /** @inheritDocs
diff --git a/modules/eddsa/src/main/scala/gs/crypto/v0/eddsa/Ed25519Verifier.scala b/modules/eddsa/src/main/scala/gs/crypto/v0/eddsa/Ed25519Verifier.scala
index 5a00dd4..c054aea 100644
--- a/modules/eddsa/src/main/scala/gs/crypto/v0/eddsa/Ed25519Verifier.scala
+++ b/modules/eddsa/src/main/scala/gs/crypto/v0/eddsa/Ed25519Verifier.scala
@@ -4,7 +4,7 @@ import cats.effect.Sync
 import gs.crypto.v0.Signature
 import gs.crypto.v0.SignatureValidity
 import gs.crypto.v0.SignatureVerifier
-import org.bouncycastle.crypto.params.Ed25519PublicKeyParameters
+import java.security.PublicKey
 
 /** Implementation of [[SignatureVerifier]] that uses the Ed25519 system to
   * verify signatures.
@@ -15,15 +15,18 @@ import org.bouncycastle.crypto.params.Ed25519PublicKeyParameters
   *   The public key.
   */
 final class Ed25519Verifier[F[_]: Sync](
-  publicKey: Array[Byte]
+  publicKey: PublicKey
 ) extends SignatureVerifier[F]:
-  private lazy val params = new Ed25519PublicKeyParameters(publicKey)
 
   /** @inheritDocs
     */
-  override def verify(signature: Signature): F[SignatureValidity] =
+  override def verify(
+    signature: Signature,
+    data: Array[Byte] // TODO: CLEAN UP
+  ): F[SignatureValidity] =
     Sync[F].delay {
-      val s = new org.bouncycastle.crypto.signers.Ed25519Signer()
-      val _ = s.init(false, params)
-      SignatureValidity(s.verifySignature(signature.unwrap()))
+      val s = java.security.Signature.getInstance(Ed25519.Algorithm)
+      val _ = s.initVerify(publicKey)
+      val _ = s.update(data)
+      SignatureValidity(s.verify(signature.unwrap()))
     }
diff --git a/modules/eddsa/src/test/scala/gs/crypto/v0/eddsa/Ed25519Tests.scala b/modules/eddsa/src/test/scala/gs/crypto/v0/eddsa/Ed25519Tests.scala
new file mode 100644
index 0000000..1d977bf
--- /dev/null
+++ b/modules/eddsa/src/test/scala/gs/crypto/v0/eddsa/Ed25519Tests.scala
@@ -0,0 +1,61 @@
+package gs.crypto.v0.eddsa
+
+import cats.effect.IO
+import cats.effect.unsafe.IORuntime
+import gs.crypto.v0.KeyLoader
+import gs.crypto.v0.SignatureValidity
+import java.security.PrivateKey
+import java.security.PublicKey
+import java.util.UUID
+import munit.Location
+
+class Ed25519Tests extends munit.FunSuite:
+  import Ed25519Tests.Resources
+
+  given IORuntime = IORuntime.global
+
+  def iotest(
+    name: String
+  )(
+    f: => IO[Unit]
+  )(
+    using
+    Location
+  ): Unit =
+    test(name)(f.unsafeRunSync())
+
+  val keyLoader = KeyLoader.resourceLoader[IO]()
+
+  iotest(
+    "should sign some data and verify that signature"
+  ) {
+    val data = UUID.randomUUID().toString()
+    loadKeysOrFail().flatMap { case (publicKey, privateKey) =>
+      val signer   = new Ed25519Signer[IO](privateKey)
+      val verifier = new Ed25519Verifier[IO](publicKey)
+
+      for
+        signature <- signer.sign(data)
+        validity  <- verifier.verify(signature, data.getBytes())
+      yield assertEquals(validity, SignatureValidity.Valid)
+    }
+  }
+
+  private def loadKeysOrFail(): IO[(PublicKey, PrivateKey)] =
+    keyLoader.loadPublicKey(Resources.PublicKey, Ed25519.Algorithm).flatMap {
+      case Left(_) => fail("Failed to load public key.")
+      case Right(pub) =>
+        keyLoader.loadPrivateKey(Resources.PrivateKey, Ed25519.Algorithm).map {
+          case Left(_)     => fail("Failed to load private key.")
+          case Right(priv) => (pub, priv)
+        }
+    }
+
+object Ed25519Tests:
+
+  object Resources:
+    val PublicKey: String  = "public.pem"
+    val PrivateKey: String = "private.pem"
+  end Resources
+
+end Ed25519Tests