Unfortunatly, I cant see it being that easy.
The passwords are encrypted and cannot be decrypted (easily if atall)
both systems will use a different “secret key” when creating the password hash, which means you would first have to decrypt all the passwords
then re-encrypt them in the CS-Cart format.
If however they are held in plain format (in OS) which I very much doubt, your task will be a lot easier.
SWS is correct concerning the password hashes.
OSC uses a ‘salted’ MD5 method for encoding a users password while CS-Cart is still using the standard MD5 method. These are not compatible with one another.
There is also an additional problem of both scripts storing customer data in multiple non-matching tables as well as each having a few unique fields…
Even if you were able to solve the password problem, your customers would still need to update some profile fields on the new store…
There would be such a vast improvement of your cart that most of your clients would be appreciative and not mind the extra effort.
OSC customer tables
TABLE customers
customers_id
customers_gender
customers_firstname
customers_lastname
customers_dob
customers_email_address
customers_default_address_id
customers_telephone
customers_fax
customers_password
customers_newsletter
TABLE customers_info
customers_info_id
customers_info_date_of_last_logon
customers_info_number_of_logons
customers_info_date_account_created
customers_info_date_account_last_modified
CS-Cart customer tables
TABLE cscart_users
user_id
active
user_type
user_login
cart_content
wishlist
membership_status
membership_id
referer
last_login
timestamp
password
card_name
card_type
card_number
card_expire
card_cvv2
title
firstname
lastname
company
email
phone
fax
url
tax_exempt
lang_code
TABLE cscart_user_profiles
profile_id
user_id
profile_type
b_title
b_firstname
b_lastname
b_address
b_address_2
b_city
b_county
b_state
b_country
b_zipcode
s_title
s_firstname
s_lastname
s_address
s_address_2
s_city
s_county
s_state
s_country
s_zipcode
profile_name
[quote name=‘SWS’]If however they are held in plain format (in OS) which I very much doubt, your task will be a lot easier.[/QUOTE]
I’m wondering if someone here is familiar with this problem as I have several thousands (+40) of users that need to be imported into our CS-Cart store. All the other fields are not a hassle to update, but the password field needs to be encrypted to MD5 - seemingly.
The old CMS had the passwords in plain format, so it’s only the encryption missing. “Only…” 
EDIT:
Found a solution for my problem, here: [url]http://forum.cs-cart.com/showthread.php?t=2786[/url]