diff --git a/sop-java-picocli/src/main/java/sop/cli/picocli/commands/AbstractSopCmd.java b/sop-java-picocli/src/main/java/sop/cli/picocli/commands/AbstractSopCmd.java
index 9cca658..c64922f 100644
--- a/sop-java-picocli/src/main/java/sop/cli/picocli/commands/AbstractSopCmd.java
+++ b/sop-java-picocli/src/main/java/sop/cli/picocli/commands/AbstractSopCmd.java
@@ -13,6 +13,7 @@ import java.io.ByteArrayInputStream;
 import java.io.ByteArrayOutputStream;
 import java.io.File;
 import java.io.FileInputStream;
+import java.io.FileNotFoundException;
 import java.io.FileOutputStream;
 import java.io.IOException;
 import java.io.InputStream;
@@ -21,6 +22,7 @@ import java.util.Collection;
 import java.util.Date;
 import java.util.Locale;
 import java.util.ResourceBundle;
+import java.util.regex.Pattern;
 
 public abstract class AbstractSopCmd implements Runnable {
 
@@ -40,6 +42,8 @@ public abstract class AbstractSopCmd implements Runnable {
     public static final Date BEGINNING_OF_TIME = new Date(0);
     public static final Date END_OF_TIME = new Date(8640000000000000L);
 
+    public static final Pattern PATTERN_FD = Pattern.compile("^\\d{1,3}$");
+
     protected final ResourceBundle messages;
     protected EnvironmentVariableResolver envResolver = System::getenv;
 
@@ -141,9 +145,14 @@ public abstract class AbstractSopCmd implements Runnable {
                 throw new SOPGPException.AmbiguousInput(errorMsg);
             }
 
-            String errorMsg = getMsg("sop.error.indirect_data_type.designator_fd_not_supported");
-            throw new SOPGPException.UnsupportedSpecialPrefix(errorMsg);
-
+            File fdFile = fileDescriptorFromString(trimmed);
+            try {
+                FileInputStream fileIn = new FileInputStream(fdFile);
+                return fileIn;
+            } catch (FileNotFoundException e) {
+                String errorMsg = getMsg("sop.error.indirect_data_type.file_descriptor_not_found", fdFile.getAbsolutePath());
+                throw new IOException(errorMsg, e);
+            }
         } else {
             File file = new File(trimmed);
             if (!file.exists()) {
@@ -176,9 +185,16 @@ public abstract class AbstractSopCmd implements Runnable {
             throw new SOPGPException.UnsupportedSpecialPrefix(errorMsg);
         }
 
+        // File Descriptor
         if (trimmed.startsWith(PRFX_FD)) {
-            String errorMsg = getMsg("sop.error.indirect_data_type.designator_fd_not_supported");
-            throw new SOPGPException.UnsupportedSpecialPrefix(errorMsg);
+            File fdFile = fileDescriptorFromString(trimmed);
+            try {
+                FileOutputStream fout = new FileOutputStream(fdFile);
+                return fout;
+            } catch (FileNotFoundException e) {
+                String errorMsg = getMsg("sop.error.indirect_data_type.file_descriptor_not_found", fdFile.getAbsolutePath());
+                throw new IOException(errorMsg, e);
+            }
         }
 
         File file = new File(trimmed);
@@ -194,6 +210,21 @@ public abstract class AbstractSopCmd implements Runnable {
 
         return new FileOutputStream(file);
     }
+
+    public File fileDescriptorFromString(String fdString) {
+        File fdDir = new File("/dev/fd/");
+        if (!fdDir.exists()) {
+            String errorMsg = getMsg("sop.error.indirect_data_type.designator_fd_not_supported");
+            throw new SOPGPException.UnsupportedSpecialPrefix(errorMsg);
+        }
+        String fdNumber = fdString.substring(PRFX_FD.length());
+        if (!PATTERN_FD.matcher(fdNumber).matches()) {
+            throw new IllegalArgumentException("File descriptor must be a 1-3 digit, positive number.");
+        }
+        File descriptor = new File(fdDir, fdNumber);
+        return descriptor;
+    }
+
     public static String stringFromInputStream(InputStream inputStream) throws IOException {
         try {
             ByteArrayOutputStream byteOut = new ByteArrayOutputStream();
diff --git a/sop-java-picocli/src/main/resources/msg_sop.properties b/sop-java-picocli/src/main/resources/msg_sop.properties
index fce60c5..7530994 100644
--- a/sop-java-picocli/src/main/resources/msg_sop.properties
+++ b/sop-java-picocli/src/main/resources/msg_sop.properties
@@ -48,6 +48,7 @@ sop.error.input.stdin_not_openpgp_data=Standard Input appears not to contain val
 sop.error.indirect_data_type.ambiguous_filename=File name '%s' is ambiguous. File with the same name exists on the filesystem.
 sop.error.indirect_data_type.environment_variable_not_set=Environment variable '%s' not set.
 sop.error.indirect_data_type.environment_variable_empty=Environment variable '%s' is empty.
+sop.error.indirect_data_type.file_descriptor_not_found=File descriptor '%s' not found.
 sop.error.indirect_data_type.input_file_does_not_exist=Input file '%s' does not exist.
 sop.error.indirect_data_type.input_not_a_file=Input file '%s' is not a file.
 sop.error.indirect_data_type.output_file_already_exists=Output file '%s' already exists.
diff --git a/sop-java-picocli/src/main/resources/msg_sop_de.properties b/sop-java-picocli/src/main/resources/msg_sop_de.properties
index acbfb68..6848777 100644
--- a/sop-java-picocli/src/main/resources/msg_sop_de.properties
+++ b/sop-java-picocli/src/main/resources/msg_sop_de.properties
@@ -48,6 +48,7 @@ sop.error.input.stdin_not_openpgp_data=Standard-Eingabe enth
 sop.error.indirect_data_type.ambiguous_filename=Dateiname '%s' ist mehrdeutig. Datei mit dem selben Namen existiert im Dateisystem.
 sop.error.indirect_data_type.environment_variable_not_set=Umgebungsvariable '%s' nicht gesetzt.
 sop.error.indirect_data_type.environment_variable_empty=Umgebungsvariable '%s' ist leer.
+sop.error.indirect_data_type.file_descriptor_not_found=File Descriptor '%s' nicht gefunden.
 sop.error.indirect_data_type.input_file_does_not_exist=Quelldatei '%s' existiert nicht.
 sop.error.indirect_data_type.input_not_a_file=Quelldatei '%s' ist keine Datei.
 sop.error.indirect_data_type.output_file_already_exists=Zieldatei '%s' existiert bereits.
diff --git a/sop-java-picocli/src/test/java/sop/cli/picocli/commands/AbstractSopCmdTest.java b/sop-java-picocli/src/test/java/sop/cli/picocli/commands/AbstractSopCmdTest.java
index 9f383f5..aed420b 100644
--- a/sop-java-picocli/src/test/java/sop/cli/picocli/commands/AbstractSopCmdTest.java
+++ b/sop-java-picocli/src/test/java/sop/cli/picocli/commands/AbstractSopCmdTest.java
@@ -145,8 +145,8 @@ public class AbstractSopCmdTest {
     }
 
     @Test
-    public void getOutput_fdUnsupportedSpecialPrefix() {
-        assertThrows(SOPGPException.UnsupportedSpecialPrefix.class, () -> abstractCmd.getOutput("@FD:IS_ILLEGAL"));
+    public void getOutput_malformedFileDescriptor() {
+        assertThrows(IllegalArgumentException.class, () -> abstractCmd.getOutput("@FD:IS_ILLEGAL"));
     }
 
     @Test