erlang crypto block_encrypt

t(Num) ->
Key = <<Num:64>>,
B = <<116,101,115,116,0,0,0,0>>,
Dest = crypto:block_encrypt(des_cbc,Key,<<0:64>>,B), 
Src = crypto:block_decrypt(des_cbc,Key,<<0:64>>,Dest),

io:format("B:~ts;Dest:~ts;src:~ts;src==b:~p;",[B,Dest,Src,B==Src]).

1> tt:t(123456).
B:test  ;Dest:T?瑲<;src:test


;src==b:true;ok
2> tt:t(123).
B:test  ;Dest:餾.眉w;src:test  ;src==b:true;ok