Winternitz Signature Scheme Using Nonadjacent Forms

Algorithm 2

WSS-N signature generation algorithm Sign.

Input: message , secret key sk and randomization elements r

Output: signature

1.  compute the NAF representation of .

2.  split into blocks of length , padding

  with zeros from the left if required.

3.  for to , set be a block of length obtained by dropping the least

  significant signed digit of .

4.  compute

5.  for to , compute

6.  compute .

7.  compute the checksum

8. split the binary representation of into

  blocks of length , padding with zeros from the left if required.

9.  for to , set be the integer encoded by the block .

10.  set .

11.  for to , compute .

12.  set .

13.  return .