diff --git a/asn1crypto/cms.py b/asn1crypto/cms.py
index c395b22..2800051 100644
--- a/asn1crypto/cms.py
+++ b/asn1crypto/cms.py
@@ -729,6 +729,10 @@ class RecipientKeyIdentifier(Sequence):
         ('other', OtherKeyAttribute, {'optional': True}),
     ]
 
+    def _setup(self):
+        super(RecipientKeyIdentifier, self)._setup()
+        self._field_map['subjectKeyIdentifier'] = self._field_map['subject_key_identifier']
+
 
 class KeyAgreementRecipientIdentifier(Choice):
     _alternatives = [
@@ -929,14 +933,6 @@ def decompressed(self):
         return self._decompressed
 
 
-class RecipientKeyIdentifier(Sequence):
-    _fields = [
-        ('subjectKeyIdentifier', OctetString),
-        ('date', GeneralizedTime, {'optional': True}),
-        ('other', OtherKeyAttribute, {'optional': True}),
-    ]
-
-
 class SMIMEEncryptionKeyPreference(Choice):
     _alternatives = [
         ('issuer_and_serial_number', IssuerAndSerialNumber, {'implicit': 0}),