Hello,

I understand that the MD5 Message Digest algorithm takes as input a message
of arbitrary length and produces as output a 128-bit ``fingerprint'' or
``message digest'' of the input.

The output representation could be:
- A binary digest will be 16 bytes long.
- A hex digest will be 32 characters long.
- A base64 digest will be 22 characters long.

***I choose to use the base64 digest for some reason.***

Note:  According to RFC 2045(page 24), Base64 encoding uses characters A-Z,
a-z, 0-9, +, /, and =.

But one thing I don't understand here. When I printed out the md5 encrypted
message in Base64 format, to my surprise, in addition to the Base64 char, I
also find a "." char.

For example, the md5_encrypted_base64_format = "Dp8.E4JGpg7rKxQa49BF9/"
When looking carefully, there is a "dot" in the 22 char base64 encrypted
string.

Why? Can anyone tell me why? Other than the "dot" char, do I expect more
non-Base64 char?  I need this info to build my regular expression for base64
format.

Thanks,
Kian