64 lines
1.9 KiB
Plaintext
64 lines
1.9 KiB
Plaintext
=pod
|
|
|
|
=head1 NAME
|
|
|
|
EVP_OpenInit, EVP_OpenUpdate, EVP_OpenFinal - EVP envelope decryption
|
|
|
|
=head1 SYNOPSIS
|
|
|
|
#include <openssl/evp.h>
|
|
|
|
int EVP_OpenInit(EVP_CIPHER_CTX *ctx,EVP_CIPHER *type,unsigned char *ek,
|
|
int ekl,unsigned char *iv,EVP_PKEY *priv);
|
|
int EVP_OpenUpdate(EVP_CIPHER_CTX *ctx, unsigned char *out,
|
|
int *outl, unsigned char *in, int inl);
|
|
int EVP_OpenFinal(EVP_CIPHER_CTX *ctx, unsigned char *out,
|
|
int *outl);
|
|
|
|
=head1 DESCRIPTION
|
|
|
|
The EVP envelope routines are a high level interface to envelope
|
|
decryption. They decrypt a public key encrypted symmetric key and
|
|
then decrypt data using it.
|
|
|
|
EVP_OpenInit() initializes a cipher context B<ctx> for decryption
|
|
with cipher B<type>. It decrypts the encrypted symmetric key of length
|
|
B<ekl> bytes passed in the B<ek> parameter using the private key B<priv>.
|
|
The IV is supplied in the B<iv> parameter.
|
|
|
|
EVP_OpenUpdate() and EVP_OpenFinal() have exactly the same properties
|
|
as the EVP_DecryptUpdate() and EVP_DecryptFinal() routines, as
|
|
documented on the L<EVP_EncryptInit(3)|EVP_EncryptInit(3)> manual
|
|
page.
|
|
|
|
=head1 NOTES
|
|
|
|
It is possible to call EVP_OpenInit() twice in the same way as
|
|
EVP_DecryptInit(). The first call should have B<priv> set to NULL
|
|
and (after setting any cipher parameters) it should be called again
|
|
with B<type> set to NULL.
|
|
|
|
If the cipher passed in the B<type> parameter is a variable length
|
|
cipher then the key length will be set to the value of the recovered
|
|
key length. If the cipher is a fixed length cipher then the recovered
|
|
key length must match the fixed cipher length.
|
|
|
|
=head1 RETURN VALUES
|
|
|
|
EVP_OpenInit() returns 0 on error or a non zero integer (actually the
|
|
recovered secret key size) if successful.
|
|
|
|
EVP_OpenUpdate() returns 1 for success or 0 for failure.
|
|
|
|
EVP_OpenFinal() returns 0 if the decrypt failed or 1 for success.
|
|
|
|
=head1 SEE ALSO
|
|
|
|
L<evp(3)|evp(3)>, L<rand(3)|rand(3)>,
|
|
L<EVP_EncryptInit(3)|EVP_EncryptInit(3)>,
|
|
L<EVP_SealInit(3)|EVP_SealInit(3)>
|
|
|
|
=head1 HISTORY
|
|
|
|
=cut
|