1*2175Sjp161948=pod 2*2175Sjp161948 3*2175Sjp161948=head1 NAME 4*2175Sjp161948 5*2175Sjp161948EVP_OpenInit, EVP_OpenUpdate, EVP_OpenFinal - EVP envelope decryption 6*2175Sjp161948 7*2175Sjp161948=head1 SYNOPSIS 8*2175Sjp161948 9*2175Sjp161948 #include <openssl/evp.h> 10*2175Sjp161948 11*2175Sjp161948 int EVP_OpenInit(EVP_CIPHER_CTX *ctx,EVP_CIPHER *type,unsigned char *ek, 12*2175Sjp161948 int ekl,unsigned char *iv,EVP_PKEY *priv); 13*2175Sjp161948 int EVP_OpenUpdate(EVP_CIPHER_CTX *ctx, unsigned char *out, 14*2175Sjp161948 int *outl, unsigned char *in, int inl); 15*2175Sjp161948 int EVP_OpenFinal(EVP_CIPHER_CTX *ctx, unsigned char *out, 16*2175Sjp161948 int *outl); 17*2175Sjp161948 18*2175Sjp161948=head1 DESCRIPTION 19*2175Sjp161948 20*2175Sjp161948The EVP envelope routines are a high level interface to envelope 21*2175Sjp161948decryption. They decrypt a public key encrypted symmetric key and 22*2175Sjp161948then decrypt data using it. 23*2175Sjp161948 24*2175Sjp161948EVP_OpenInit() initializes a cipher context B<ctx> for decryption 25*2175Sjp161948with cipher B<type>. It decrypts the encrypted symmetric key of length 26*2175Sjp161948B<ekl> bytes passed in the B<ek> parameter using the private key B<priv>. 27*2175Sjp161948The IV is supplied in the B<iv> parameter. 28*2175Sjp161948 29*2175Sjp161948EVP_OpenUpdate() and EVP_OpenFinal() have exactly the same properties 30*2175Sjp161948as the EVP_DecryptUpdate() and EVP_DecryptFinal() routines, as 31*2175Sjp161948documented on the L<EVP_EncryptInit(3)|EVP_EncryptInit(3)> manual 32*2175Sjp161948page. 33*2175Sjp161948 34*2175Sjp161948=head1 NOTES 35*2175Sjp161948 36*2175Sjp161948It is possible to call EVP_OpenInit() twice in the same way as 37*2175Sjp161948EVP_DecryptInit(). The first call should have B<priv> set to NULL 38*2175Sjp161948and (after setting any cipher parameters) it should be called again 39*2175Sjp161948with B<type> set to NULL. 40*2175Sjp161948 41*2175Sjp161948If the cipher passed in the B<type> parameter is a variable length 42*2175Sjp161948cipher then the key length will be set to the value of the recovered 43*2175Sjp161948key length. If the cipher is a fixed length cipher then the recovered 44*2175Sjp161948key length must match the fixed cipher length. 45*2175Sjp161948 46*2175Sjp161948=head1 RETURN VALUES 47*2175Sjp161948 48*2175Sjp161948EVP_OpenInit() returns 0 on error or a non zero integer (actually the 49*2175Sjp161948recovered secret key size) if successful. 50*2175Sjp161948 51*2175Sjp161948EVP_OpenUpdate() returns 1 for success or 0 for failure. 52*2175Sjp161948 53*2175Sjp161948EVP_OpenFinal() returns 0 if the decrypt failed or 1 for success. 54*2175Sjp161948 55*2175Sjp161948=head1 SEE ALSO 56*2175Sjp161948 57*2175Sjp161948L<evp(3)|evp(3)>, L<rand(3)|rand(3)>, 58*2175Sjp161948L<EVP_EncryptInit(3)|EVP_EncryptInit(3)>, 59*2175Sjp161948L<EVP_SealInit(3)|EVP_SealInit(3)> 60*2175Sjp161948 61*2175Sjp161948=head1 HISTORY 62*2175Sjp161948 63*2175Sjp161948=cut 64