1*4724848cSchristos=pod 2*4724848cSchristos 3*4724848cSchristos=head1 NAME 4*4724848cSchristos 5*4724848cSchristosEVP_OpenInit, EVP_OpenUpdate, EVP_OpenFinal - EVP envelope decryption 6*4724848cSchristos 7*4724848cSchristos=head1 SYNOPSIS 8*4724848cSchristos 9*4724848cSchristos #include <openssl/evp.h> 10*4724848cSchristos 11*4724848cSchristos int EVP_OpenInit(EVP_CIPHER_CTX *ctx, EVP_CIPHER *type, unsigned char *ek, 12*4724848cSchristos int ekl, unsigned char *iv, EVP_PKEY *priv); 13*4724848cSchristos int EVP_OpenUpdate(EVP_CIPHER_CTX *ctx, unsigned char *out, 14*4724848cSchristos int *outl, unsigned char *in, int inl); 15*4724848cSchristos int EVP_OpenFinal(EVP_CIPHER_CTX *ctx, unsigned char *out, int *outl); 16*4724848cSchristos 17*4724848cSchristos=head1 DESCRIPTION 18*4724848cSchristos 19*4724848cSchristosThe EVP envelope routines are a high-level interface to envelope 20*4724848cSchristosdecryption. They decrypt a public key encrypted symmetric key and 21*4724848cSchristosthen decrypt data using it. 22*4724848cSchristos 23*4724848cSchristosEVP_OpenInit() initializes a cipher context B<ctx> for decryption 24*4724848cSchristoswith cipher B<type>. It decrypts the encrypted symmetric key of length 25*4724848cSchristosB<ekl> bytes passed in the B<ek> parameter using the private key B<priv>. 26*4724848cSchristosThe IV is supplied in the B<iv> parameter. 27*4724848cSchristos 28*4724848cSchristosEVP_OpenUpdate() and EVP_OpenFinal() have exactly the same properties 29*4724848cSchristosas the EVP_DecryptUpdate() and EVP_DecryptFinal() routines, as 30*4724848cSchristosdocumented on the L<EVP_EncryptInit(3)> manual 31*4724848cSchristospage. 32*4724848cSchristos 33*4724848cSchristos=head1 NOTES 34*4724848cSchristos 35*4724848cSchristosIt is possible to call EVP_OpenInit() twice in the same way as 36*4724848cSchristosEVP_DecryptInit(). The first call should have B<priv> set to NULL 37*4724848cSchristosand (after setting any cipher parameters) it should be called again 38*4724848cSchristoswith B<type> set to NULL. 39*4724848cSchristos 40*4724848cSchristosIf the cipher passed in the B<type> parameter is a variable length 41*4724848cSchristoscipher then the key length will be set to the value of the recovered 42*4724848cSchristoskey length. If the cipher is a fixed length cipher then the recovered 43*4724848cSchristoskey length must match the fixed cipher length. 44*4724848cSchristos 45*4724848cSchristos=head1 RETURN VALUES 46*4724848cSchristos 47*4724848cSchristosEVP_OpenInit() returns 0 on error or a non zero integer (actually the 48*4724848cSchristosrecovered secret key size) if successful. 49*4724848cSchristos 50*4724848cSchristosEVP_OpenUpdate() returns 1 for success or 0 for failure. 51*4724848cSchristos 52*4724848cSchristosEVP_OpenFinal() returns 0 if the decrypt failed or 1 for success. 53*4724848cSchristos 54*4724848cSchristos=head1 SEE ALSO 55*4724848cSchristos 56*4724848cSchristosL<evp(7)>, L<RAND_bytes(3)>, 57*4724848cSchristosL<EVP_EncryptInit(3)>, 58*4724848cSchristosL<EVP_SealInit(3)> 59*4724848cSchristos 60*4724848cSchristos=head1 COPYRIGHT 61*4724848cSchristos 62*4724848cSchristosCopyright 2000-2020 The OpenSSL Project Authors. All Rights Reserved. 63*4724848cSchristos 64*4724848cSchristosLicensed under the OpenSSL license (the "License"). You may not use 65*4724848cSchristosthis file except in compliance with the License. You can obtain a copy 66*4724848cSchristosin the file LICENSE in the source distribution or at 67*4724848cSchristosL<https://www.openssl.org/source/license.html>. 68*4724848cSchristos 69*4724848cSchristos=cut 70