...

src/pEpEngine.c

@@ -840,16 +840,18 @@ DYNAMIC_API PEP_STATUS decrypt_and_verify(
         default:
             {
                 gpgme_decrypt_result_t gpgme_decrypt_result = _session->gpgme_op_decrypt_result(_session->ctx);
-                result = PEP_CANNOT_DECRYPT_UNKNOWN;
+                result = PEP_DECRYPT_NO_KEY;
 
                 if (gpgme_decrypt_result != NULL) {
-                    *keylist = new_stringlist(gpgme_decrypt_result->unsupported_algorithm);
+                    if (gpgme_decrypt_result->unsupported_algorithm)
+                        *keylist = new_stringlist(gpgme_decrypt_result->unsupported_algorithm);
+                    else
+                        *keylist = new_stringlist("");
                     assert(*keylist);
                     if (*keylist == NULL) {
                         result = PEP_OUT_OF_MEMORY;
                         break;
                     }
-                    
                     stringlist_t *_keylist = *keylist;
                     for (gpgme_recipient_t r = gpgme_decrypt_result->recipients; r != NULL; r = r->next) {
                         _keylist = stringlist_add(_keylist, r->keyid);

src/pEpEngine.h

@@ -166,8 +166,7 @@ DYNAMIC_API void free_stringlist(stringlist_t *stringlist);
 //		csize (in)		size of cipher text
 //		ptext (out)		pointer to internal buffer with plain text
 //		psize (out)		size of plain text
-//		keylist (out)	list of key ids which where used to encrypt or NULL on
-//		                error
+//		keylist (out)	list of key ids which where used to encrypt
 //
 //	return value:
 //		PEP_UNENCRYPTED				message was unencrypted and not signed
@@ -182,6 +181,9 @@ DYNAMIC_API void free_stringlist(stringlist_t *stringlist);
 //	    the ownerships of ptext as well as keylist are going to the caller
 //	    the caller must use free() (or an Windoze pEp_free()) and
 //	    free_stringlist() to free them
+//
+//      if this function failes an error message may be the first element of
+//      keylist and the other elements may be the keys used for encryption
 
 DYNAMIC_API PEP_STATUS decrypt_and_verify(
         PEP_SESSION session, const char *ctext, size_t csize,