Here are the data structures with brief descriptions:

CCanonicalContext_t	An aggregator to maintain the internal state of canonicalization during intermediate calculations
CHmacContext_t	An aggregator to maintain the internal state of HMAC calculations
CSigV4ConstString_t	A library structure holding the string and length values of parameters to be sorted and standardized. This allows for a layer of abstraction during the canonicalization step of the V4 signing process
CSigV4Credentials_t	Configurations for the AWS credentials used to generate the Signing Key
CSigV4CryptoInterface_t	The cryptography interface used to supply the user-defined hash implementation
CSigV4DateTime_t	An aggregator representing the individually parsed elements of the user-provided date parameter. This is used to verify the complete date representation, and construct the final ISO 8601 string
CSigV4HttpParameters_t	Configurations of the HTTP request used to create the Canonical Request
CSigV4KeyValuePair_t	A key-value pair data structure that allows for sorting of SigV4 string values using internal comparison functions, and provides additional stability to quickSort(), to comply with Misra rule 21.9
CSigV4Parameters_t	Complete configurations required for generating "String to Sign" and "Signing Key" values
CSigV4String_t	A library structure holding the string and length values of parameters to be sorted and standardized. This allows for a layer of abstraction during the canonicalization step of the V4 signing process