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evp.pod 1.8 KB

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  1. =pod
  2. =head1 NAME
  3. evp - high-level cryptographic functions
  4. =head1 SYNOPSIS
  5. #include <openssl/evp.h>
  6. =head1 DESCRIPTION
  7. The EVP library provides a high-level interface to cryptographic
  8. functions.
  9. B<EVP_Seal>I<...> and B<EVP_Open>I<...> provide public key encryption
  10. and decryption to implement digital "envelopes".
  11. The B<EVP_Sign>I<...> and B<EVP_Verify>I<...> functions implement
  12. digital signatures.
  13. Symmetric encryption is available with the B<EVP_Encrypt>I<...>
  14. functions. The B<EVP_Digest>I<...> functions provide message digests.
  15. The B<EVP_PKEY>I<...> functions provide a high level interface to
  16. asymmetric algorithms.
  17. Algorithms are loaded with OpenSSL_add_all_algorithms(3).
  18. All the symmetric algorithms (ciphers), digests and asymmetric algorithms
  19. (public key algorithms) can be replaced by ENGINE modules providing alternative
  20. implementations. If ENGINE implementations of ciphers or digests are registered
  21. as defaults, then the various EVP functions will automatically use those
  22. implementations automatically in preference to built in software
  23. implementations. For more information, consult the engine(3) man page.
  24. Although low level algorithm specific functions exist for many algorithms
  25. their use is discouraged. They cannot be used with an ENGINE and ENGINE
  26. versions of new algorithms cannot be accessed using the low level functions.
  27. Also makes code harder to adapt to new algorithms and some options are not
  28. cleanly supported at the low level and some operations are more efficient
  29. using the high level interface.
  30. =head1 SEE ALSO
  31. L<EVP_DigestInit(3)|EVP_DigestInit(3)>,
  32. L<EVP_EncryptInit(3)|EVP_EncryptInit(3)>,
  33. L<EVP_OpenInit(3)|EVP_OpenInit(3)>,
  34. L<EVP_SealInit(3)|EVP_SealInit(3)>,
  35. L<EVP_SignInit(3)|EVP_SignInit(3)>,
  36. L<EVP_VerifyInit(3)|EVP_VerifyInit(3)>,
  37. L<OpenSSL_add_all_algorithms(3)|OpenSSL_add_all_algorithms(3)>,
  38. L<engine(3)|engine(3)>
  39. =cut