The RSAExponentOfOne class generates so-called 'exponent-of-one' RSA keys. These keys are special RSA keys, in the sense that the output buffer matches the input buffer for an RSA encryption or decryption. Practically, this means that if you generate a key-exchange message using a RSAPKCS1KeyExchangeFormatter class that was initialized with such a special key, the resulting key exchange buffer will include the secret key unencrypted. Exponent-of-one keys are very useful when you're in the debugging stage of your application. You can use these keys instead of 'normal' RSA keys, and the entire system keeps working as expected. The only difference is that the 'encrypted' data is the same as the unencrypted data - a very useful feature for debugging purposes.