Password Callback

SourcePro : Secure Communication Module User’s Guide : PART II Secure Sockets Package : Advanced Topics : Using the Secure Sockets Callbacks : Password Callback

Password Callback

The password callback is invoked when an attempt is made to construct a key from encrypted data. The password callback supplies the password with which the key was encrypted. The signature of the callback function is:

extern “C” int passwordCallback(char *buffer, int bufLen, int flag);

The following table describes the parameters and their definitions.

Parameter	Definition
char *buffer	The buffer into which the null terminated password string must be copied.
int bufLen	The maximum length of buffer. The length of the password plus the null terminator must be less than or equal to this number.
int flag	The flag parameter can be safely ignored, but it must be specified in the signature of the callback.The password callback is also called by the cryptographic library when the cryptographic library tries to write a key. In this case, the flag parameter is 1. The Secure Sockets package does not support writing keys, so this parameter is not needed.

The password callback function must return the length of the password.

If the password copied into buffer is incorrect, the exception RWUnableToReadPrivateKeyError is thrown.

For more information, see the example in examples\secsock\manual\InlineEncryptedKeyServer.cpp.