diff --git a/lib/Document.php b/lib/Document.php
index 8319b49b..3fdb4f98 100644
--- a/lib/Document.php
+++ b/lib/Document.php
@@ -194,6 +194,13 @@ public function createProperty(string $name, $value = null, ?array $parameters =
             $class = $this->getClassNameForPropertyValue($valueType);
         }
 
+        // A base64 encoded value is binary, whatever the default value type of
+        // the property: vCard 2.1 and 3.0 embed keys and sounds this way too,
+        // not only photos and logos.
+        if (!$class && $this->isBase64Encoded($parameters['ENCODING'] ?? null)) {
+            $class = Property\Binary::class;
+        }
+
         // If the value parameter is not set or set to something we do not recognize
         // we do not attempt to interpret or parse the datass value as specified in
         // https://datatracker.ietf.org/doc/html/rfc5545#section-3.2.20
@@ -205,6 +212,18 @@ public function createProperty(string $name, $value = null, ?array $parameters =
         return new $class($this, $name, $value, $parameters, $group, $lineIndex, $lineString);
     }
 
+    /**
+     * Whether an ENCODING parameter value says the value is base64 encoded.
+     */
+    private function isBase64Encoded(mixed $encoding): bool
+    {
+        if (is_array($encoding)) {
+            $encoding = reset($encoding);
+        }
+
+        return is_string($encoding) && in_array(strtoupper($encoding), ['B', 'BASE64'], true);
+    }
+
     /**
      * This method returns a full class-name for a value parameter.
      *
diff --git a/tests/VObject/Base64EncodingTest.php b/tests/VObject/Base64EncodingTest.php
new file mode 100644
index 00000000..bf7a6b8b
--- /dev/null
+++ b/tests/VObject/Base64EncodingTest.php
@@ -0,0 +1,43 @@
+<?php
+
+namespace Sabre\VObject;
+
+use PHPUnit\Framework\TestCase;
+
+class Base64EncodingTest extends TestCase
+{
+    public function testKeyInVCard30(): void
+    {
+        $input = "BEGIN:VCARD\r\nVERSION:3.0\r\nKEY;ENCODING=b;TYPE=PGP:LS0tLS1CRUdJTg==\r\nEND:VCARD\r\n";
+        $vcard = Reader::read($input);
+
+        self::assertInstanceOf(Property\Binary::class, $vcard->KEY);
+        self::assertEquals('-----BEGIN', $vcard->KEY->getValue());
+        self::assertEquals($input, $vcard->serialize());
+    }
+
+    public function testSoundInVCard21(): void
+    {
+        $vcard = Reader::read("BEGIN:VCARD\r\nVERSION:2.1\r\nSOUND;ENCODING=BASE64;TYPE=WAVE:UklGRg==\r\nEND:VCARD\r\n");
+
+        self::assertInstanceOf(Property\Binary::class, $vcard->SOUND);
+        self::assertEquals('RIFF', $vcard->SOUND->getValue());
+    }
+
+    public function testConversionToVCard40GivesADataUri(): void
+    {
+        $vcard = Reader::read("BEGIN:VCARD\r\nVERSION:3.0\r\nKEY;ENCODING=b;TYPE=PGP:LS0tLS1CRUdJTg==\r\nEND:VCARD\r\n");
+
+        $converted = $vcard->convert(Document::VCARD40);
+
+        self::assertStringStartsWith('data:', (string) $converted->KEY);
+        self::assertStringEndsWith(';base64,LS0tLS1CRUdJTg==', (string) $converted->KEY);
+    }
+
+    public function testValueParameterComesFirst(): void
+    {
+        $vcard = Reader::read("BEGIN:VCARD\r\nVERSION:3.0\r\nKEY;ENCODING=b;VALUE=text:LS0tLS1CRUdJTg==\r\nEND:VCARD\r\n");
+
+        self::assertInstanceOf(Property\Text::class, $vcard->KEY);
+    }
+}