To write a list of EncryptedObject out to disk and then read it back in try this approach:
In[972]:= $fPrefix = "encrypted-messages-";
In[973]:= rndFileName[] :=
StringJoin[{$fPrefix, ToString@RandomInteger[{10000, 20000}]}]
In[974]:= SetDirectory[$HomeDirectory];
In[975]:=
key = GenerateSymmetricKey[
Method -> <|"Cipher" -> "Blowfish", "KeySize" -> 192,
"BlockMode" -> "CFB"|>];
In[993]:= message = "
Little Secret Hoppy Ale / 55 IBU / 6% ABV
Little Secret falls somewhere between Session IPA and American \
Pale Ale. Using a blend of three malts and four hops, Little Secret \
presents an herbal, fruity hop character punctuated by a citrus \
bitterness that lasts through the finish.";
In[992]:= encrypted = Encrypt[key, message];
In[1004]:= messages =
Table[encrypted, {i, 1,
25}]; (* list of encrypted messages (all the same in this \
example)*)
In[1005]:= fname = rndFileName[]
Out[1005]= "encrypted-messages-12078"
In[1006]:= out = OpenWrite[fname];
In[1007]:= Write[out, messages]
In[1008]:= Close[out]
Out[1008]= "encrypted-messages-12078"
In[1012]:= Head[First@Flatten@ReadList[fname]]
Out[1012]= EncryptedObject
