Oracle: DBMS_CRYPTO.HASH

Calculate a 256-bit SHA-2 hash from a CLOB

declare
   h raw(32); -- 32 * 8-bit = 256-bit

   c clob := q'[foo
bar
baz]';

begin
   h := dbms_crypto.HASH(c, dbms_crypto.hash_sh256);
   dbms_output.put_line('hash: ' || rawtohex(h));
end;
/

hash: 33B28259443FA31A0052030C1E5482E2145219AD02B6E226CD5D3F096FC7E897

Calculate an MD5 hash from a string (varchar2)

declare

   txt varchar2(100) := 'foo, bar and baz.';
   md5 raw(16); -- MD5 is 128 = 16 * 8 bits

begin

   md5 := dbms_crypto.hash(
            utl_i18n.string_to_raw(txt, 'AL32UTF8'),
            dbms_crypto.hash_md5
          );

   dbms_output.put_line('MD5 is: ' || md5);

end;
/

See also