#include
void OpenSSL_add_all_algorithms(void); void OpenSSL_add_all_ciphers(void); void OpenSSL_add_all_digests(void);
void EVP_cleanup(void);
_O_p_e_n_S_S_L___a_d_d___a_l_l___d_i_g_e_s_t_s_(_) adds all digest algorithms to the table.
_O_p_e_n_S_S_L___a_d_d___a_l_l___a_l_g_o_r_i_t_h_m_s_(_) adds all algorithms to the table (digests and ciphers).
_O_p_e_n_S_S_L___a_d_d___a_l_l___c_i_p_h_e_r_s_(_) adds all encryption algorithms to the table including password based encryption algorithms.
_E_V_P___c_l_e_a_n_u_p_(_) removes all ciphers and digests from the table.
An application does not need to add algorithms to use them explicitly, for example by _E_V_P___s_h_a_1_(_). It just needs to add them if it (or any of the functions it calls) needs to lookup algorithms.
The cipher and digest lookup functions are used in many parts of the library. If the table is not initialized several functions will misbehave and complain they cannot find algorithms. This includes the PEM, PKCS#12, SSL and S/MIME libraries. This is a common query in the OpenSSL mailing lists.
Calling _O_p_e_n_S_S_L___a_d_d___a_l_l___a_l_g_o_r_i_t_h_m_s_(_) links in all algorithms: as a result a statically linked executable can be quite large. If this is important it is possible to just add the required ciphers and digests.