pgcrypto

Hi,
i created extension pgcrypto on public with postgres user.But while
trying to use from my own schma suppose qa.

when i run digest in function in my qa

CREATE OR REPLACE FUNCTION sha1(bytea) returns text AS $$
SELECT encode(digest($1, 'sha1'), 'hex')
$$ LANGUAGE SQL STRICT IMMUTABLE;

it return error;
when i install pgcrypto using postgres user on qa,installed all pgcrypto
function placed in qa function it looks confused.

what should i do how to access the pgcrypto of public and we need to create
extension on each schema..??