1*4724848cSchristos=pod 2*4724848cSchristos 3*4724848cSchristos=head1 NAME 4*4724848cSchristos 5*4724848cSchristosBIO_f_cipher, BIO_set_cipher, BIO_get_cipher_status, BIO_get_cipher_ctx - cipher BIO filter 6*4724848cSchristos 7*4724848cSchristos=head1 SYNOPSIS 8*4724848cSchristos 9*4724848cSchristos=for comment multiple includes 10*4724848cSchristos 11*4724848cSchristos #include <openssl/bio.h> 12*4724848cSchristos #include <openssl/evp.h> 13*4724848cSchristos 14*4724848cSchristos const BIO_METHOD *BIO_f_cipher(void); 15*4724848cSchristos void BIO_set_cipher(BIO *b, const EVP_CIPHER *cipher, 16*4724848cSchristos unsigned char *key, unsigned char *iv, int enc); 17*4724848cSchristos int BIO_get_cipher_status(BIO *b) 18*4724848cSchristos int BIO_get_cipher_ctx(BIO *b, EVP_CIPHER_CTX **pctx) 19*4724848cSchristos 20*4724848cSchristos=head1 DESCRIPTION 21*4724848cSchristos 22*4724848cSchristosBIO_f_cipher() returns the cipher BIO method. This is a filter 23*4724848cSchristosBIO that encrypts any data written through it, and decrypts any data 24*4724848cSchristosread from it. It is a BIO wrapper for the cipher routines 25*4724848cSchristosEVP_CipherInit(), EVP_CipherUpdate() and EVP_CipherFinal(). 26*4724848cSchristos 27*4724848cSchristosCipher BIOs do not support BIO_gets() or BIO_puts(). 28*4724848cSchristos 29*4724848cSchristosBIO_flush() on an encryption BIO that is being written through is 30*4724848cSchristosused to signal that no more data is to be encrypted: this is used 31*4724848cSchristosto flush and possibly pad the final block through the BIO. 32*4724848cSchristos 33*4724848cSchristosBIO_set_cipher() sets the cipher of BIO B<b> to B<cipher> using key B<key> 34*4724848cSchristosand IV B<iv>. B<enc> should be set to 1 for encryption and zero for 35*4724848cSchristosdecryption. 36*4724848cSchristos 37*4724848cSchristosWhen reading from an encryption BIO the final block is automatically 38*4724848cSchristosdecrypted and checked when EOF is detected. BIO_get_cipher_status() 39*4724848cSchristosis a BIO_ctrl() macro which can be called to determine whether the 40*4724848cSchristosdecryption operation was successful. 41*4724848cSchristos 42*4724848cSchristosBIO_get_cipher_ctx() is a BIO_ctrl() macro which retrieves the internal 43*4724848cSchristosBIO cipher context. The retrieved context can be used in conjunction 44*4724848cSchristoswith the standard cipher routines to set it up. This is useful when 45*4724848cSchristosBIO_set_cipher() is not flexible enough for the applications needs. 46*4724848cSchristos 47*4724848cSchristos=head1 NOTES 48*4724848cSchristos 49*4724848cSchristosWhen encrypting BIO_flush() B<must> be called to flush the final block 50*4724848cSchristosthrough the BIO. If it is not then the final block will fail a subsequent 51*4724848cSchristosdecrypt. 52*4724848cSchristos 53*4724848cSchristosWhen decrypting an error on the final block is signaled by a zero 54*4724848cSchristosreturn value from the read operation. A successful decrypt followed 55*4724848cSchristosby EOF will also return zero for the final read. BIO_get_cipher_status() 56*4724848cSchristosshould be called to determine if the decrypt was successful. 57*4724848cSchristos 58*4724848cSchristosAs always, if BIO_gets() or BIO_puts() support is needed then it can 59*4724848cSchristosbe achieved by preceding the cipher BIO with a buffering BIO. 60*4724848cSchristos 61*4724848cSchristos=head1 RETURN VALUES 62*4724848cSchristos 63*4724848cSchristosBIO_f_cipher() returns the cipher BIO method. 64*4724848cSchristos 65*4724848cSchristosBIO_set_cipher() does not return a value. 66*4724848cSchristos 67*4724848cSchristosBIO_get_cipher_status() returns 1 for a successful decrypt and 0 68*4724848cSchristosfor failure. 69*4724848cSchristos 70*4724848cSchristosBIO_get_cipher_ctx() currently always returns 1. 71*4724848cSchristos 72*4724848cSchristos=head1 COPYRIGHT 73*4724848cSchristos 74*4724848cSchristosCopyright 2000-2016 The OpenSSL Project Authors. All Rights Reserved. 75*4724848cSchristos 76*4724848cSchristosLicensed under the OpenSSL license (the "License"). You may not use 77*4724848cSchristosthis file except in compliance with the License. You can obtain a copy 78*4724848cSchristosin the file LICENSE in the source distribution or at 79*4724848cSchristosL<https://www.openssl.org/source/license.html>. 80*4724848cSchristos 81*4724848cSchristos=cut 82