diff --git a/poppler/Form.cc b/poppler/Form.cc
index c5b7078..c7f18f5 100644
--- a/poppler/Form.cc
+++ b/poppler/Form.cc
@@ -1433,7 +1433,7 @@ void FormFieldSignature::parseInfo()
 
   // check if subfilter is supported for signature validation, only detached signatures work for now
   sig_dict.dictLookup("SubFilter", &subfilterName);
-  if (subfilterName.isName("adbe.pkcs7.detached")) {
+  if (subfilterName.isName("adbe.pkcs7.detached") || subfilterName.isName("adbe.pkcs7.sha1")) {
     signature_info->setSubFilterSupport(true);
   }
 
diff --git a/poppler/SignatureHandler.cc b/poppler/SignatureHandler.cc
index c741958..861c7fa 100644
--- a/poppler/SignatureHandler.cc
+++ b/poppler/SignatureHandler.cc
@@ -193,7 +193,8 @@ NSSCMSSignerInfo *SignatureHandler::CMS_SignerInfoCreate(NSSCMSSignedData * cms_
   if (!signerInfo) {
     printf("Error in NSS_CMSSignedData_GetSignerInfo()\n");
     return NULL;
-  } else {
+  }
+  else {
     return signerInfo;
   }
 }
@@ -219,10 +220,33 @@ NSSCMSVerificationStatus SignatureHandler::validateSignature(unsigned char *sign
   if ((NSS_CMSSignerInfo_GetSigningCertificate(CMSSignerInfo, CERT_GetDefaultCertDB())) == NULL)
     CMSSignerInfo->verificationStatus = NSSCMSVS_SigningCertNotFound;
 
-  if (NSS_CMSSignerInfo_Verify(CMSSignerInfo, &digest, NULL) != SECSuccess) {
+  if (CMSSignedData->contentInfo.content.data != NULL)
+  {
+    /*
+      This means it's not a detached type signature
+      so the digest is contained in SignedData->contentInfo
+    */
+    if(memcmp(digest.data, CMSSignedData->contentInfo.content.data->data, hash_length) == 0
+        && digest.len == CMSSignedData->contentInfo.content.data->len)
+    {
+      PORT_Free(digest_buffer);
+      return NSSCMSVS_GoodSignature;
+    }
+    else 
+    {
+      PORT_Free(digest_buffer);
+      return NSSCMSVS_DigestMismatch;
+    }
+
+  }
+  else if (NSS_CMSSignerInfo_Verify(CMSSignerInfo, &digest, NULL) != SECSuccess)
+  {
+
     PORT_Free(digest_buffer);
     return CMSSignerInfo->verificationStatus;
-  } else {
+  } 
+  else 
+  {
     PORT_Free(digest_buffer);
     return NSSCMSVS_GoodSignature;
   }