Typo.

[openssl.git] / doc / crypto / evp.pod

diff --git a/doc/crypto/evp.pod b/doc/crypto/evp.pod
index f089dd49a219b57c6abcc08eb196988b6085e9d1..9faa349243af460499070337e6b3c6e0111b258b 100644 (file)
--- a/doc/crypto/evp.pod
+++ b/doc/crypto/evp.pod
@@ -10,7 +10,7 @@ evp - high-level cryptographic functions
 
 =head1 DESCRIPTION
 
-The EVP library provided a high-level interface to cryptographic
+The EVP library provides a high-level interface to cryptographic
 functions.
 
 B<EVP_Seal>I<...> and B<EVP_Open>I<...> provide public key encryption
@@ -22,8 +22,25 @@ digital signatures.
 Symmetric encryption is available with the B<EVP_Encrypt>I<...>
 functions.  The B<EVP_Digest>I<...> functions provide message digests.
 
+The B<EVP_PKEY>I<...> functions provide a high level interface to
+asymmetric algorithms.
+
 Algorithms are loaded with OpenSSL_add_all_algorithms(3).
 
+All the symmetric algorithms (ciphers), digests and asymmetric algorithms
+(public key algorithms) can be replaced by ENGINE modules providing alternative
+implementations. If ENGINE implementations of ciphers or digests are registered
+as defaults, then the various EVP functions will automatically use those
+implementations automatically in preference to built in software
+implementations. For more information, consult the engine(3) man page.
+
+Although low level algorithm specific functions exist for many algorithms
+their use is discouraged. They cannot be used with an ENGINE and ENGINE
+versions of new algorithms cannot be accessed using the low level functions.
+Also makes code harder to adapt to new algorithms and some options are not 
+cleanly supported at the low level and some operations are more efficient
+using the high level interface.
+
 =head1 SEE ALSO
 
 L<EVP_DigestInit(3)|EVP_DigestInit(3)>,
@@ -32,6 +49,7 @@ L<EVP_OpenInit(3)|EVP_OpenInit(3)>,
 L<EVP_SealInit(3)|EVP_SealInit(3)>,
 L<EVP_SignInit(3)|EVP_SignInit(3)>,
 L<EVP_VerifyInit(3)|EVP_VerifyInit(3)>,
-L<OpenSSL_add_all_algorithms(3)|OpenSSL_add_all_algorithms(3)>
+L<OpenSSL_add_all_algorithms(3)|OpenSSL_add_all_algorithms(3)>,
+L<engine(3)|engine(3)>
 
 =cut