HP Open Source Security for OpenVMS Volume 2: HP SSL for ...

4 SSL Programming Concepts
SSL Programming Concepts
HP SSL Data Structures
This chapter discusses how to write application programs using HP SSL on OpenVMS. The SSL library
provides APIs supporting three SSL protocols: SSL Version 2 (SSLv2), SSL Version 3 (SSLv3), and TLS
Version 1 (TLSv1). You can write an HP SSL application program in C or C++.
This chapter provides the following information:
A description of the seven HP SSL data structures
How to configure and obtain certificates
An HP SSL programming tutorial that shows the implementation of a simple HP SSL client and server
program using HP SSL APIs
4.1 HP SSL Data Structures
Before you start SSL application development, you should understand the data structures used for SSL APIs,
and the relationships between the data structures.
SSL APIs use data structures to hold various types of information about SSL sessions and connections. The
most important structures are SSL_CTX and SSL. Usually, one SSL_CTX structure exists per SSL application
program, and an SSL structure is created every time a new SSL connection is created. An SSL structure
inherits configuration information from the SSL_CTX structure when it is created.
Table 4-1 shows the APIs commonly used for creating and deallocating data structures.
Table 4-1 APIs for Data Structure Creation and Deallocation
Data Structure API for Creation API for Deallocation
SSL_CTX SSL_CTX_new() SSL_CTX_free()
SSL SSL_new() SSL_free()
SSL_SESSION SSL_SESSION_new() SSL_SESSION_free()
BIO BIO_new() BIO_free()
X509 X509_new() X509_free()
RSA RSA_new() RSA_free()
DH DH_new() DH_free()
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