Internet Explorer Cannot Import Odd-Sized Keys

When you use Microsoft Internet Explorer and you attempt to import cryptographic keys that are made up of two different-sized modulus, you may receive one of the following error messages.

Internet Explorer 5.01 on Microsoft Windows 98: Internet Explorer 5.01 on Microsoft Windows 2000:

The Microsoft Cryptographic Service Providers (CSPs), which support Rivest-Shamir-Adleman (RSA) algorithms, require that the two prime values that are multiplied to generate the modulus be exactly half the length of the modulus. For example, if the modulus is 1024 bits (with the most significant bit set to 1), the two primes are both assumed to be 512 bits (again, the most significant bit is set to 1). Some RSA keys have prime values that do not meet this criterion. For example, some RSA keys generated by cryptography products have one prime that is 513 bits and one that is 511 bits. The Microsoft PFX code and the Microsoft CSPs do not support keys of this type. You are not be able to import these keys.