diff --git a/src/lib/crypto.pl b/src/lib/crypto.pl
index af03e7d6..1f78c8cb 100644
--- a/src/lib/crypto.pl
+++ b/src/lib/crypto.pl
@@ -592,7 +592,6 @@ crypto_data_decrypt(CipherText0, Algorithm, Key, IV, PlainText, Options) :-
         encoding_chars(Encoding, AAD0, AAD),
         must_be(atom, Encoding),
         member(Encoding, [utf8,octet]),
-        must_be(list, CipherText0),
         encoding_chars(octet, CipherText0, CipherText1),
         maplist(char_code, TagChars, Tag),
         append(CipherText1, TagChars, CipherText),