Today I added CRC32MBS and MD5MBS functions so you can get the checksum of a blob on your server. Also the REALbasic plugins get a new MD5StringMBS function, so you can calculate files MD5 locally and on the server if you need to compare files without copying them to the other side:
CRC32MBS(data as blob) as integer
Returns CRC of data in the blob. The return value is a 32 bit unsigned integer which is stored in a 64 bit integer.
MD5MBS(data as blob) as string
Returns MD5 checksum of data in the blob. The return string is a 32 character long hex string.
Download here: monkeybreadsoftware.de/realserver/