Jan. 22, 2011, 7:54 p.m.
posted by gelassen
An issue with all algorithms is whether or not they are interoperable. The simple answer is that if you stick with the major algorithms, you won’t run into many problems. Almost all encryption programs come ready to use DES, 3DES, AES, and RSA. Fewer are able to handle DH key exchange and even fewer than that handle ECC. If you are going to be exchanging encrypted data with a partner, customer, friend, or significant other, it’s best to make sure that their programs are set up to use the same algorithms that your programs use. Not only do you have to worry about the interoperability or compatibility of the algorithms, but you also have to consider the file formats of the original data, too. For example, if you encrypt a graphics file as a .tif format and your partner can handle only postscript files, the decryption and viewing isn’t going to work correctly.
Interoperability becomes much more of an issue when you move into PKI (Public Key Infrastructure). PKI systems can be complex and expensive, and if you are using this type of system to authenticate users, customers, and partners, it’s very important that their systems and yours be able to talk to one another. I cover this aspect in detail in Chapter 6.