Cryptography Export Restrictions
Cryptography is subject to export restrictions. Some governments, including the United States government, currently place export restrictions on encryption technology. Other governments also place import restrictions on encryption technology. The availability of the encryption technologies that are described in this guide and the actual strength of the encryption that you are allowed to use for security varies according to the export or import restrictions for a specific geographical area.
Windows 2000 and other security products you use might be export-controlled in geographic areas where your organization has offices. If so, security systems are going to be limited in cryptographic strength for those areas. Give cryptography export restrictions careful consideration when you are planning security systems.
In general, products and technology with exportable cryptography provide much less security than the nonexportable versions of the same products and technologies. Exportable security technology usually limits cryptography to much shorter symmetric encryption keys than the key lengths that are allowed for the nonexportable version of the same technology. For example, the nonexportable version of a secure mail product might use bulk encryption keys with a length of 128 bits. However, the bulk encryption keys for the exportable version of the secure mail product might be limited to a key length of 40 bits or 56 bits. Likewise, the nonexportable version of a secure Web browser might support 128-bit encryption for secure Web communications, whereas the exportable version might support only 40-bit or 56-bit secure communications. Shorter encryption keys are much more vulnerable to brute force attacks than are longer keys (keys that are at least 64 bits in length generally provide strong protection against brute force attacks). Therefore, consider using exportable technology only to protect information of relatively low value.
If you provide cryptography-based security between groups that use exportable technology and groups that use nonexportable technology, the cryptographic strength is limited to the lowest common denominator that is supported by both the exportable technology and the nonexportable technology. Security is generally limited by the exportable technology. For example, encrypted secure mail between groups that use exportable cryptography and groups that use nonexportable cryptography is limited to the longest key length supported by the exportable cryptography (for example, 40 bits or 56 bits). You cannot use the exportable technology to read secure mail that was encrypted with an 128-bit key.
Take the current limitations of exportable cryptography into account when developing your security plans. However, note that the cryptographic strength of the available technologies for exportable security products is subject to change when government policies on cryptography export change. The actual strength of the available cryptography technology might change before your security plans are implemented. For the latest information about the cryptography technology available for the products you intend to deploy, contact each applicable vendor.
For more information about the current cryptography restrictions and policies for Microsoft security products, see the Microsoft Security Advisor link on the Web Resources page at http://windows.microsoft.com/windows2000/reskit/webresources .