解决方法
Jacksum：
http://www.jonelo.de/java/jacksum/index.html
cksum algorithm: POSIX 1003.2 CRC algorithm
length: 32 bits
type: crc
since: Jacksum 1.0.0
comment: - under BeOS it is /bin/cksum
- under FreeBSD it is /usr/bin/cksum
- under HP-UX it is /usr/bin/cksum and
/usr/bin/sum -p
- under IBM AIX it is /usr/bin/cksum
- under Linux it is /usr/bin/cksum
它是开源的.
