diff --git a/lib/marcel/mime_type/definitions.rb b/lib/marcel/mime_type/definitions.rb
index 09ce72b..b9dfeab 100644
--- a/lib/marcel/mime_type/definitions.rb
+++ b/lib/marcel/mime_type/definitions.rb
@@ -37,6 +37,7 @@
 Marcel::MimeType.extend("audio/ogg", extensions: %w( ogg oga ), magic: [[0, 'OggS', [[29, 'vorbis']]]])
 
 Marcel::MimeType.extend "image/vnd.dwg", magic: [[0, "AC10"]]
+Marcel::MimeType.extend "application/pkcs8", magic: [[0, '-----BEGIN PRIVATE KEY-----']], extensions: %w( p8 )
 
 Marcel::MimeType.extend "application/x-x509-ca-cert", magic: [[0, '-----BEGIN CERTIFICATE-----']], extensions: %w( pem ), parents: "application/x-x509-cert;format=pem"
 
diff --git a/test/fixtures/magic/application/pkcs8/pkcs8_key.p8 b/test/fixtures/magic/application/pkcs8/pkcs8_key.p8
new file mode 100644
index 0000000..61ee26d
--- /dev/null
+++ b/test/fixtures/magic/application/pkcs8/pkcs8_key.p8
@@ -0,0 +1,10 @@
+-----BEGIN PRIVATE KEY-----
+MIIBVQIBADANBgkqhkiG9w0BAQEFAASCAT8wggE7AgEAAkEAsyAfVMJ5DEAqMnMP
+bwL5+eqZvys5Fyhv8+r/g/dhiz2EdGXthahSGw+99+Zv12EFvn5eDX86a0rO9bQN
+hjQJcwIDAQABAj91jJ8DAJxvbaxDbz6xm0Jwv4Ql8DeG+wJ9D7qe37kjpiIabMfE
+JyYw+cpdbpgQ04OdQLVoRNqSgiQFIrJxhkECIQDcRM9H+RvF0W6Bjgec3/8P4ciC
+m5ddpMkffeyLXhPibQIhANAuvOtaXXBVoUODb6YEdOLnu3XeIV6KhrG11adepS9f
+AiEAsiHTn9kNZMUiIRPDhFKB604k4bsChnClVhp4GZ1TZ2ECIQCTKFaWrxvZqk4C
+IUisu/273z6dxNUltRodSIGse7ScVQIhAJmPYxR8oc7q0HpMvXgfQhEs9cHFlNHG
+XDpubBUpqjwK
+-----END PRIVATE KEY-----