diff --git a/core/jvm/src/main/scala/works/iterative/core/FileSupportPlatformSpecific.scala b/core/jvm/src/main/scala/works/iterative/core/FileSupportPlatformSpecific.scala
index a179a80..451a924 100644
--- a/core/jvm/src/main/scala/works/iterative/core/FileSupportPlatformSpecific.scala
+++ b/core/jvm/src/main/scala/works/iterative/core/FileSupportPlatformSpecific.scala
@@ -1,6 +1,18 @@
 package works.iterative.core
 
+import zio.*
+import zio.stream.*
+
 trait FileSupportPlatformSpecific:
   type FileRepr = java.io.File
 
-  extension (f: FileRepr) def name: String = f.getName
+  extension (f: FileRepr)
+    def name: String = f.getName
+    def toStream: Stream[Throwable, Byte] =
+      ZStream.fromInputStreamScoped(
+        ZIO.fromAutoCloseable(
+          ZIO.attempt(new java.io.FileInputStream(f)).refineOrDie {
+            case e: java.io.IOException => e
+          }
+        )
+      )

diff --git a/core/jvm/src/main/scala/works/iterative/core/FileSupportPlatformSpecific.scala b/core/jvm/src/main/scala/works/iterative/core/FileSupportPlatformSpecific.scala
index a179a80..451a924 100644
--- a/core/jvm/src/main/scala/works/iterative/core/FileSupportPlatformSpecific.scala
+++ b/core/jvm/src/main/scala/works/iterative/core/FileSupportPlatformSpecific.scala
@@ -1,6 +1,18 @@
 package works.iterative.core
 
+import zio.*
+import zio.stream.*
+
 trait FileSupportPlatformSpecific:
   type FileRepr = java.io.File
 
-  extension (f: FileRepr) def name: String = f.getName
+  extension (f: FileRepr)
+    def name: String = f.getName
+    def toStream: Stream[Throwable, Byte] =
+      ZStream.fromInputStreamScoped(
+        ZIO.fromAutoCloseable(
+          ZIO.attempt(new java.io.FileInputStream(f)).refineOrDie {
+            case e: java.io.IOException => e
+          }
+        )
+      )
diff --git a/core/jvm/src/main/scala/works/iterative/core/service/impl/JcaDigestGenerator.scala b/core/jvm/src/main/scala/works/iterative/core/service/impl/JcaDigestGenerator.scala
deleted file mode 100644
index 0fbb024..0000000
--- a/core/jvm/src/main/scala/works/iterative/core/service/impl/JcaDigestGenerator.scala
+++ /dev/null
@@ -1,25 +0,0 @@
-package works.iterative.core
-package service
-package impl
-
-import zio.*
-import zio.stream.*
-
-class JcaDigestGenerator extends DigestGenerator:
-
-  override def generateDigest(
-      algorithm: DigestAlgorithm,
-      content: UStream[Byte]
-  ): UIO[Digest] = {
-    for
-      md <- ZIO.attempt(
-        java.security.MessageDigest.getInstance(algorithm.value)
-      )
-      _ <- content.runForeachChunk(e => ZIO.attempt(md.update(e.toArray)))
-      digest <- ZIO.attempt(md.digest())
-    yield Digest(algorithm, digest)
-  }.orDie
-
-object JcaDigestGenerator:
-  val layer: ULayer[DigestGenerator] =
-    ZLayer.succeed(new JcaDigestGenerator)

diff --git a/core/jvm/src/main/scala/works/iterative/core/FileSupportPlatformSpecific.scala b/core/jvm/src/main/scala/works/iterative/core/FileSupportPlatformSpecific.scala
index a179a80..451a924 100644
--- a/core/jvm/src/main/scala/works/iterative/core/FileSupportPlatformSpecific.scala
+++ b/core/jvm/src/main/scala/works/iterative/core/FileSupportPlatformSpecific.scala
@@ -1,6 +1,18 @@
 package works.iterative.core
 
+import zio.*
+import zio.stream.*
+
 trait FileSupportPlatformSpecific:
   type FileRepr = java.io.File
 
-  extension (f: FileRepr) def name: String = f.getName
+  extension (f: FileRepr)
+    def name: String = f.getName
+    def toStream: Stream[Throwable, Byte] =
+      ZStream.fromInputStreamScoped(
+        ZIO.fromAutoCloseable(
+          ZIO.attempt(new java.io.FileInputStream(f)).refineOrDie {
+            case e: java.io.IOException => e
+          }
+        )
+      )
diff --git a/core/jvm/src/main/scala/works/iterative/core/service/impl/JcaDigestGenerator.scala b/core/jvm/src/main/scala/works/iterative/core/service/impl/JcaDigestGenerator.scala
deleted file mode 100644
index 0fbb024..0000000
--- a/core/jvm/src/main/scala/works/iterative/core/service/impl/JcaDigestGenerator.scala
+++ /dev/null
@@ -1,25 +0,0 @@
-package works.iterative.core
-package service
-package impl
-
-import zio.*
-import zio.stream.*
-
-class JcaDigestGenerator extends DigestGenerator:
-
-  override def generateDigest(
-      algorithm: DigestAlgorithm,
-      content: UStream[Byte]
-  ): UIO[Digest] = {
-    for
-      md <- ZIO.attempt(
-        java.security.MessageDigest.getInstance(algorithm.value)
-      )
-      _ <- content.runForeachChunk(e => ZIO.attempt(md.update(e.toArray)))
-      digest <- ZIO.attempt(md.digest())
-    yield Digest(algorithm, digest)
-  }.orDie
-
-object JcaDigestGenerator:
-  val layer: ULayer[DigestGenerator] =
-    ZLayer.succeed(new JcaDigestGenerator)
diff --git a/core/jvm/src/main/scala/works/iterative/core/service/impl/JcaDigestService.scala b/core/jvm/src/main/scala/works/iterative/core/service/impl/JcaDigestService.scala
new file mode 100644
index 0000000..8c88818
--- /dev/null
+++ b/core/jvm/src/main/scala/works/iterative/core/service/impl/JcaDigestService.scala
@@ -0,0 +1,26 @@
+package works.iterative.core
+package service
+package impl
+
+import zio.*
+import zio.stream.*
+
+class JcaDigestService extends DigestService:
+
+  override def digest[E](
+      algorithm: DigestAlgorithm,
+      content: Stream[E, Byte]
+  ): IO[E, Digest] =
+    for
+      md <- ZIO
+        .attempt(
+          java.security.MessageDigest.getInstance(algorithm.value)
+        )
+        .orDie
+      _ <- content.runForeachChunk(e => ZIO.attempt(md.update(e.toArray)).orDie)
+      digest <- ZIO.attempt(md.digest()).orDie
+    yield Digest(algorithm, digest)
+
+object JcaDigestGenerator:
+  val layer: ULayer[DigestService] =
+    ZLayer.succeed(new JcaDigestService)

diff --git a/core/jvm/src/main/scala/works/iterative/core/FileSupportPlatformSpecific.scala b/core/jvm/src/main/scala/works/iterative/core/FileSupportPlatformSpecific.scala
index a179a80..451a924 100644
--- a/core/jvm/src/main/scala/works/iterative/core/FileSupportPlatformSpecific.scala
+++ b/core/jvm/src/main/scala/works/iterative/core/FileSupportPlatformSpecific.scala
@@ -1,6 +1,18 @@
 package works.iterative.core
 
+import zio.*
+import zio.stream.*
+
 trait FileSupportPlatformSpecific:
   type FileRepr = java.io.File
 
-  extension (f: FileRepr) def name: String = f.getName
+  extension (f: FileRepr)
+    def name: String = f.getName
+    def toStream: Stream[Throwable, Byte] =
+      ZStream.fromInputStreamScoped(
+        ZIO.fromAutoCloseable(
+          ZIO.attempt(new java.io.FileInputStream(f)).refineOrDie {
+            case e: java.io.IOException => e
+          }
+        )
+      )
diff --git a/core/jvm/src/main/scala/works/iterative/core/service/impl/JcaDigestGenerator.scala b/core/jvm/src/main/scala/works/iterative/core/service/impl/JcaDigestGenerator.scala
deleted file mode 100644
index 0fbb024..0000000
--- a/core/jvm/src/main/scala/works/iterative/core/service/impl/JcaDigestGenerator.scala
+++ /dev/null
@@ -1,25 +0,0 @@
-package works.iterative.core
-package service
-package impl
-
-import zio.*
-import zio.stream.*
-
-class JcaDigestGenerator extends DigestGenerator:
-
-  override def generateDigest(
-      algorithm: DigestAlgorithm,
-      content: UStream[Byte]
-  ): UIO[Digest] = {
-    for
-      md <- ZIO.attempt(
-        java.security.MessageDigest.getInstance(algorithm.value)
-      )
-      _ <- content.runForeachChunk(e => ZIO.attempt(md.update(e.toArray)))
-      digest <- ZIO.attempt(md.digest())
-    yield Digest(algorithm, digest)
-  }.orDie
-
-object JcaDigestGenerator:
-  val layer: ULayer[DigestGenerator] =
-    ZLayer.succeed(new JcaDigestGenerator)
diff --git a/core/jvm/src/main/scala/works/iterative/core/service/impl/JcaDigestService.scala b/core/jvm/src/main/scala/works/iterative/core/service/impl/JcaDigestService.scala
new file mode 100644
index 0000000..8c88818
--- /dev/null
+++ b/core/jvm/src/main/scala/works/iterative/core/service/impl/JcaDigestService.scala
@@ -0,0 +1,26 @@
+package works.iterative.core
+package service
+package impl
+
+import zio.*
+import zio.stream.*
+
+class JcaDigestService extends DigestService:
+
+  override def digest[E](
+      algorithm: DigestAlgorithm,
+      content: Stream[E, Byte]
+  ): IO[E, Digest] =
+    for
+      md <- ZIO
+        .attempt(
+          java.security.MessageDigest.getInstance(algorithm.value)
+        )
+        .orDie
+      _ <- content.runForeachChunk(e => ZIO.attempt(md.update(e.toArray)).orDie)
+      digest <- ZIO.attempt(md.digest()).orDie
+    yield Digest(algorithm, digest)
+
+object JcaDigestGenerator:
+  val layer: ULayer[DigestService] =
+    ZLayer.succeed(new JcaDigestService)
diff --git a/core/shared/src/main/scala/works/iterative/core/Digest.scala b/core/shared/src/main/scala/works/iterative/core/Digest.scala
index 17db0e2..e61a4fc 100644
--- a/core/shared/src/main/scala/works/iterative/core/Digest.scala
+++ b/core/shared/src/main/scala/works/iterative/core/Digest.scala
@@ -1,6 +1,6 @@
 package works.iterative.core
 
-import works.iterative.core.service.DigestGenerator
+import works.iterative.core.service.DigestService
 
 import zio.*
 
@@ -19,5 +19,5 @@
   def compute(
       algorithm: DigestAlgorithm,
       value: Array[Byte]
-  ): URIO[DigestGenerator, Digest] =
-    DigestGenerator.generateDigest(algorithm, value)
+  ): URIO[DigestService, Digest] =
+    DigestService.digest(algorithm, value)

diff --git a/core/jvm/src/main/scala/works/iterative/core/FileSupportPlatformSpecific.scala b/core/jvm/src/main/scala/works/iterative/core/FileSupportPlatformSpecific.scala
index a179a80..451a924 100644
--- a/core/jvm/src/main/scala/works/iterative/core/FileSupportPlatformSpecific.scala
+++ b/core/jvm/src/main/scala/works/iterative/core/FileSupportPlatformSpecific.scala
@@ -1,6 +1,18 @@
 package works.iterative.core
 
+import zio.*
+import zio.stream.*
+
 trait FileSupportPlatformSpecific:
   type FileRepr = java.io.File
 
-  extension (f: FileRepr) def name: String = f.getName
+  extension (f: FileRepr)
+    def name: String = f.getName
+    def toStream: Stream[Throwable, Byte] =
+      ZStream.fromInputStreamScoped(
+        ZIO.fromAutoCloseable(
+          ZIO.attempt(new java.io.FileInputStream(f)).refineOrDie {
+            case e: java.io.IOException => e
+          }
+        )
+      )
diff --git a/core/jvm/src/main/scala/works/iterative/core/service/impl/JcaDigestGenerator.scala b/core/jvm/src/main/scala/works/iterative/core/service/impl/JcaDigestGenerator.scala
deleted file mode 100644
index 0fbb024..0000000
--- a/core/jvm/src/main/scala/works/iterative/core/service/impl/JcaDigestGenerator.scala
+++ /dev/null
@@ -1,25 +0,0 @@
-package works.iterative.core
-package service
-package impl
-
-import zio.*
-import zio.stream.*
-
-class JcaDigestGenerator extends DigestGenerator:
-
-  override def generateDigest(
-      algorithm: DigestAlgorithm,
-      content: UStream[Byte]
-  ): UIO[Digest] = {
-    for
-      md <- ZIO.attempt(
-        java.security.MessageDigest.getInstance(algorithm.value)
-      )
-      _ <- content.runForeachChunk(e => ZIO.attempt(md.update(e.toArray)))
-      digest <- ZIO.attempt(md.digest())
-    yield Digest(algorithm, digest)
-  }.orDie
-
-object JcaDigestGenerator:
-  val layer: ULayer[DigestGenerator] =
-    ZLayer.succeed(new JcaDigestGenerator)
diff --git a/core/jvm/src/main/scala/works/iterative/core/service/impl/JcaDigestService.scala b/core/jvm/src/main/scala/works/iterative/core/service/impl/JcaDigestService.scala
new file mode 100644
index 0000000..8c88818
--- /dev/null
+++ b/core/jvm/src/main/scala/works/iterative/core/service/impl/JcaDigestService.scala
@@ -0,0 +1,26 @@
+package works.iterative.core
+package service
+package impl
+
+import zio.*
+import zio.stream.*
+
+class JcaDigestService extends DigestService:
+
+  override def digest[E](
+      algorithm: DigestAlgorithm,
+      content: Stream[E, Byte]
+  ): IO[E, Digest] =
+    for
+      md <- ZIO
+        .attempt(
+          java.security.MessageDigest.getInstance(algorithm.value)
+        )
+        .orDie
+      _ <- content.runForeachChunk(e => ZIO.attempt(md.update(e.toArray)).orDie)
+      digest <- ZIO.attempt(md.digest()).orDie
+    yield Digest(algorithm, digest)
+
+object JcaDigestGenerator:
+  val layer: ULayer[DigestService] =
+    ZLayer.succeed(new JcaDigestService)
diff --git a/core/shared/src/main/scala/works/iterative/core/Digest.scala b/core/shared/src/main/scala/works/iterative/core/Digest.scala
index 17db0e2..e61a4fc 100644
--- a/core/shared/src/main/scala/works/iterative/core/Digest.scala
+++ b/core/shared/src/main/scala/works/iterative/core/Digest.scala
@@ -1,6 +1,6 @@
 package works.iterative.core
 
-import works.iterative.core.service.DigestGenerator
+import works.iterative.core.service.DigestService
 
 import zio.*
 
@@ -19,5 +19,5 @@
   def compute(
       algorithm: DigestAlgorithm,
       value: Array[Byte]
-  ): URIO[DigestGenerator, Digest] =
-    DigestGenerator.generateDigest(algorithm, value)
+  ): URIO[DigestService, Digest] =
+    DigestService.digest(algorithm, value)
diff --git a/core/shared/src/main/scala/works/iterative/core/UserMessage.scala b/core/shared/src/main/scala/works/iterative/core/UserMessage.scala
index 37bda09..0391884 100644
--- a/core/shared/src/main/scala/works/iterative/core/UserMessage.scala
+++ b/core/shared/src/main/scala/works/iterative/core/UserMessage.scala
@@ -9,5 +9,8 @@
     s"${id}[${args.mkString(", ")}]"
 
 object UserMessage:
+  def withMessage(id: MessageId)(t: Throwable): UserMessage =
+    UserMessage(id, t.getMessage())
+
   given Conversion[MessageId, UserMessage] with
     def apply(id: MessageId): UserMessage = UserMessage(id)

diff --git a/core/jvm/src/main/scala/works/iterative/core/FileSupportPlatformSpecific.scala b/core/jvm/src/main/scala/works/iterative/core/FileSupportPlatformSpecific.scala
index a179a80..451a924 100644
--- a/core/jvm/src/main/scala/works/iterative/core/FileSupportPlatformSpecific.scala
+++ b/core/jvm/src/main/scala/works/iterative/core/FileSupportPlatformSpecific.scala
@@ -1,6 +1,18 @@
 package works.iterative.core
 
+import zio.*
+import zio.stream.*
+
 trait FileSupportPlatformSpecific:
   type FileRepr = java.io.File
 
-  extension (f: FileRepr) def name: String = f.getName
+  extension (f: FileRepr)
+    def name: String = f.getName
+    def toStream: Stream[Throwable, Byte] =
+      ZStream.fromInputStreamScoped(
+        ZIO.fromAutoCloseable(
+          ZIO.attempt(new java.io.FileInputStream(f)).refineOrDie {
+            case e: java.io.IOException => e
+          }
+        )
+      )
diff --git a/core/jvm/src/main/scala/works/iterative/core/service/impl/JcaDigestGenerator.scala b/core/jvm/src/main/scala/works/iterative/core/service/impl/JcaDigestGenerator.scala
deleted file mode 100644
index 0fbb024..0000000
--- a/core/jvm/src/main/scala/works/iterative/core/service/impl/JcaDigestGenerator.scala
+++ /dev/null
@@ -1,25 +0,0 @@
-package works.iterative.core
-package service
-package impl
-
-import zio.*
-import zio.stream.*
-
-class JcaDigestGenerator extends DigestGenerator:
-
-  override def generateDigest(
-      algorithm: DigestAlgorithm,
-      content: UStream[Byte]
-  ): UIO[Digest] = {
-    for
-      md <- ZIO.attempt(
-        java.security.MessageDigest.getInstance(algorithm.value)
-      )
-      _ <- content.runForeachChunk(e => ZIO.attempt(md.update(e.toArray)))
-      digest <- ZIO.attempt(md.digest())
-    yield Digest(algorithm, digest)
-  }.orDie
-
-object JcaDigestGenerator:
-  val layer: ULayer[DigestGenerator] =
-    ZLayer.succeed(new JcaDigestGenerator)
diff --git a/core/jvm/src/main/scala/works/iterative/core/service/impl/JcaDigestService.scala b/core/jvm/src/main/scala/works/iterative/core/service/impl/JcaDigestService.scala
new file mode 100644
index 0000000..8c88818
--- /dev/null
+++ b/core/jvm/src/main/scala/works/iterative/core/service/impl/JcaDigestService.scala
@@ -0,0 +1,26 @@
+package works.iterative.core
+package service
+package impl
+
+import zio.*
+import zio.stream.*
+
+class JcaDigestService extends DigestService:
+
+  override def digest[E](
+      algorithm: DigestAlgorithm,
+      content: Stream[E, Byte]
+  ): IO[E, Digest] =
+    for
+      md <- ZIO
+        .attempt(
+          java.security.MessageDigest.getInstance(algorithm.value)
+        )
+        .orDie
+      _ <- content.runForeachChunk(e => ZIO.attempt(md.update(e.toArray)).orDie)
+      digest <- ZIO.attempt(md.digest()).orDie
+    yield Digest(algorithm, digest)
+
+object JcaDigestGenerator:
+  val layer: ULayer[DigestService] =
+    ZLayer.succeed(new JcaDigestService)
diff --git a/core/shared/src/main/scala/works/iterative/core/Digest.scala b/core/shared/src/main/scala/works/iterative/core/Digest.scala
index 17db0e2..e61a4fc 100644
--- a/core/shared/src/main/scala/works/iterative/core/Digest.scala
+++ b/core/shared/src/main/scala/works/iterative/core/Digest.scala
@@ -1,6 +1,6 @@
 package works.iterative.core
 
-import works.iterative.core.service.DigestGenerator
+import works.iterative.core.service.DigestService
 
 import zio.*
 
@@ -19,5 +19,5 @@
   def compute(
       algorithm: DigestAlgorithm,
       value: Array[Byte]
-  ): URIO[DigestGenerator, Digest] =
-    DigestGenerator.generateDigest(algorithm, value)
+  ): URIO[DigestService, Digest] =
+    DigestService.digest(algorithm, value)
diff --git a/core/shared/src/main/scala/works/iterative/core/UserMessage.scala b/core/shared/src/main/scala/works/iterative/core/UserMessage.scala
index 37bda09..0391884 100644
--- a/core/shared/src/main/scala/works/iterative/core/UserMessage.scala
+++ b/core/shared/src/main/scala/works/iterative/core/UserMessage.scala
@@ -9,5 +9,8 @@
     s"${id}[${args.mkString(", ")}]"
 
 object UserMessage:
+  def withMessage(id: MessageId)(t: Throwable): UserMessage =
+    UserMessage(id, t.getMessage())
+
   given Conversion[MessageId, UserMessage] with
     def apply(id: MessageId): UserMessage = UserMessage(id)
diff --git a/core/shared/src/main/scala/works/iterative/core/service/DigestGenerator.scala b/core/shared/src/main/scala/works/iterative/core/service/DigestGenerator.scala
deleted file mode 100644
index 5cbfa3d..0000000
--- a/core/shared/src/main/scala/works/iterative/core/service/DigestGenerator.scala
+++ /dev/null
@@ -1,26 +0,0 @@
-package works.iterative.core.service
-
-import works.iterative.core.Digest
-import works.iterative.core.DigestAlgorithm
-
-import zio.*
-import zio.stream.*
-
-trait DigestGenerator:
-  def generateDigest(
-      algorithm: DigestAlgorithm,
-      content: UStream[Byte]
-  ): UIO[Digest]
-
-object DigestGenerator:
-  def generateDigest(
-      algorithm: DigestAlgorithm,
-      content: UStream[Byte]
-  ): URIO[DigestGenerator, Digest] =
-    ZIO.serviceWithZIO[DigestGenerator](_.generateDigest(algorithm, content))
-
-  def generateDigest(
-      algorithm: DigestAlgorithm,
-      content: Array[Byte]
-  ): URIO[DigestGenerator, Digest] =
-    generateDigest(algorithm, ZStream.fromChunk(Chunk.fromArray(content)))

diff --git a/core/jvm/src/main/scala/works/iterative/core/FileSupportPlatformSpecific.scala b/core/jvm/src/main/scala/works/iterative/core/FileSupportPlatformSpecific.scala
index a179a80..451a924 100644
--- a/core/jvm/src/main/scala/works/iterative/core/FileSupportPlatformSpecific.scala
+++ b/core/jvm/src/main/scala/works/iterative/core/FileSupportPlatformSpecific.scala
@@ -1,6 +1,18 @@
 package works.iterative.core
 
+import zio.*
+import zio.stream.*
+
 trait FileSupportPlatformSpecific:
   type FileRepr = java.io.File
 
-  extension (f: FileRepr) def name: String = f.getName
+  extension (f: FileRepr)
+    def name: String = f.getName
+    def toStream: Stream[Throwable, Byte] =
+      ZStream.fromInputStreamScoped(
+        ZIO.fromAutoCloseable(
+          ZIO.attempt(new java.io.FileInputStream(f)).refineOrDie {
+            case e: java.io.IOException => e
+          }
+        )
+      )
diff --git a/core/jvm/src/main/scala/works/iterative/core/service/impl/JcaDigestGenerator.scala b/core/jvm/src/main/scala/works/iterative/core/service/impl/JcaDigestGenerator.scala
deleted file mode 100644
index 0fbb024..0000000
--- a/core/jvm/src/main/scala/works/iterative/core/service/impl/JcaDigestGenerator.scala
+++ /dev/null
@@ -1,25 +0,0 @@
-package works.iterative.core
-package service
-package impl
-
-import zio.*
-import zio.stream.*
-
-class JcaDigestGenerator extends DigestGenerator:
-
-  override def generateDigest(
-      algorithm: DigestAlgorithm,
-      content: UStream[Byte]
-  ): UIO[Digest] = {
-    for
-      md <- ZIO.attempt(
-        java.security.MessageDigest.getInstance(algorithm.value)
-      )
-      _ <- content.runForeachChunk(e => ZIO.attempt(md.update(e.toArray)))
-      digest <- ZIO.attempt(md.digest())
-    yield Digest(algorithm, digest)
-  }.orDie
-
-object JcaDigestGenerator:
-  val layer: ULayer[DigestGenerator] =
-    ZLayer.succeed(new JcaDigestGenerator)
diff --git a/core/jvm/src/main/scala/works/iterative/core/service/impl/JcaDigestService.scala b/core/jvm/src/main/scala/works/iterative/core/service/impl/JcaDigestService.scala
new file mode 100644
index 0000000..8c88818
--- /dev/null
+++ b/core/jvm/src/main/scala/works/iterative/core/service/impl/JcaDigestService.scala
@@ -0,0 +1,26 @@
+package works.iterative.core
+package service
+package impl
+
+import zio.*
+import zio.stream.*
+
+class JcaDigestService extends DigestService:
+
+  override def digest[E](
+      algorithm: DigestAlgorithm,
+      content: Stream[E, Byte]
+  ): IO[E, Digest] =
+    for
+      md <- ZIO
+        .attempt(
+          java.security.MessageDigest.getInstance(algorithm.value)
+        )
+        .orDie
+      _ <- content.runForeachChunk(e => ZIO.attempt(md.update(e.toArray)).orDie)
+      digest <- ZIO.attempt(md.digest()).orDie
+    yield Digest(algorithm, digest)
+
+object JcaDigestGenerator:
+  val layer: ULayer[DigestService] =
+    ZLayer.succeed(new JcaDigestService)
diff --git a/core/shared/src/main/scala/works/iterative/core/Digest.scala b/core/shared/src/main/scala/works/iterative/core/Digest.scala
index 17db0e2..e61a4fc 100644
--- a/core/shared/src/main/scala/works/iterative/core/Digest.scala
+++ b/core/shared/src/main/scala/works/iterative/core/Digest.scala
@@ -1,6 +1,6 @@
 package works.iterative.core
 
-import works.iterative.core.service.DigestGenerator
+import works.iterative.core.service.DigestService
 
 import zio.*
 
@@ -19,5 +19,5 @@
   def compute(
       algorithm: DigestAlgorithm,
       value: Array[Byte]
-  ): URIO[DigestGenerator, Digest] =
-    DigestGenerator.generateDigest(algorithm, value)
+  ): URIO[DigestService, Digest] =
+    DigestService.digest(algorithm, value)
diff --git a/core/shared/src/main/scala/works/iterative/core/UserMessage.scala b/core/shared/src/main/scala/works/iterative/core/UserMessage.scala
index 37bda09..0391884 100644
--- a/core/shared/src/main/scala/works/iterative/core/UserMessage.scala
+++ b/core/shared/src/main/scala/works/iterative/core/UserMessage.scala
@@ -9,5 +9,8 @@
     s"${id}[${args.mkString(", ")}]"
 
 object UserMessage:
+  def withMessage(id: MessageId)(t: Throwable): UserMessage =
+    UserMessage(id, t.getMessage())
+
   given Conversion[MessageId, UserMessage] with
     def apply(id: MessageId): UserMessage = UserMessage(id)
diff --git a/core/shared/src/main/scala/works/iterative/core/service/DigestGenerator.scala b/core/shared/src/main/scala/works/iterative/core/service/DigestGenerator.scala
deleted file mode 100644
index 5cbfa3d..0000000
--- a/core/shared/src/main/scala/works/iterative/core/service/DigestGenerator.scala
+++ /dev/null
@@ -1,26 +0,0 @@
-package works.iterative.core.service
-
-import works.iterative.core.Digest
-import works.iterative.core.DigestAlgorithm
-
-import zio.*
-import zio.stream.*
-
-trait DigestGenerator:
-  def generateDigest(
-      algorithm: DigestAlgorithm,
-      content: UStream[Byte]
-  ): UIO[Digest]
-
-object DigestGenerator:
-  def generateDigest(
-      algorithm: DigestAlgorithm,
-      content: UStream[Byte]
-  ): URIO[DigestGenerator, Digest] =
-    ZIO.serviceWithZIO[DigestGenerator](_.generateDigest(algorithm, content))
-
-  def generateDigest(
-      algorithm: DigestAlgorithm,
-      content: Array[Byte]
-  ): URIO[DigestGenerator, Digest] =
-    generateDigest(algorithm, ZStream.fromChunk(Chunk.fromArray(content)))
diff --git a/core/shared/src/main/scala/works/iterative/core/service/DigestService.scala b/core/shared/src/main/scala/works/iterative/core/service/DigestService.scala
new file mode 100644
index 0000000..883bd7a
--- /dev/null
+++ b/core/shared/src/main/scala/works/iterative/core/service/DigestService.scala
@@ -0,0 +1,26 @@
+package works.iterative.core.service
+
+import works.iterative.core.Digest
+import works.iterative.core.DigestAlgorithm
+
+import zio.*
+import zio.stream.*
+
+trait DigestService:
+  def digest[E](
+      algorithm: DigestAlgorithm,
+      content: Stream[E, Byte]
+  ): IO[E, Digest]
+
+object DigestService:
+  def digest[E](
+      algorithm: DigestAlgorithm,
+      content: Stream[E, Byte]
+  ): ZIO[DigestService, E, Digest] =
+    ZIO.serviceWithZIO[DigestService](_.digest(algorithm, content))
+
+  def digest(
+      algorithm: DigestAlgorithm,
+      content: Array[Byte]
+  ): URIO[DigestService, Digest] =
+    digest(algorithm, ZStream.fromChunk(Chunk.fromArray(content)))