CKSUM test suite:
4294967295 0 
1220704766 1 a
1219131554 3 abc
3644109718 14 message digest
2713270184 26 abcdefghijklmnopqrstuvwxyz
2547199108 56 abcdbcdecdefdefgefghfghighijhijkijkljklmklmnlmnomnopnopq
81918263 62 ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789
1939911592 80 12345678901234567890123456789012345678901234567890123456789012345678901234567890
3401932319 1000000 one million 'a' characters