| =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 |
