Edit File: BIO_f_cipher.html
<?xml version="1.0" ?> <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd"> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <title>BIO_f_cipher</title> <meta http-equiv="content-type" content="text/html; charset=utf-8" /> <link rev="made" href="mailto:root@localhost" /> </head> <body> <ul id="index"> <li><a href="#NAME">NAME</a></li> <li><a href="#SYNOPSIS">SYNOPSIS</a></li> <li><a href="#DESCRIPTION">DESCRIPTION</a></li> <li><a href="#NOTES">NOTES</a></li> <li><a href="#RETURN-VALUES">RETURN VALUES</a></li> <li><a href="#COPYRIGHT">COPYRIGHT</a></li> </ul> <h1 id="NAME">NAME</h1> <p>BIO_f_cipher, BIO_set_cipher, BIO_get_cipher_status, BIO_get_cipher_ctx - cipher BIO filter</p> <h1 id="SYNOPSIS">SYNOPSIS</h1> <pre><code> #include <openssl/bio.h> #include <openssl/evp.h> const BIO_METHOD *BIO_f_cipher(void); void BIO_set_cipher(BIO *b, const EVP_CIPHER *cipher, unsigned char *key, unsigned char *iv, int enc); int BIO_get_cipher_status(BIO *b) int BIO_get_cipher_ctx(BIO *b, EVP_CIPHER_CTX **pctx)</code></pre> <h1 id="DESCRIPTION">DESCRIPTION</h1> <p>BIO_f_cipher() returns the cipher BIO method. This is a filter BIO that encrypts any data written through it, and decrypts any data read from it. It is a BIO wrapper for the cipher routines EVP_CipherInit(), EVP_CipherUpdate() and EVP_CipherFinal().</p> <p>Cipher BIOs do not support BIO_gets() or BIO_puts().</p> <p>BIO_flush() on an encryption BIO that is being written through is used to signal that no more data is to be encrypted: this is used to flush and possibly pad the final block through the BIO.</p> <p>BIO_set_cipher() sets the cipher of BIO <b>b</b> to <b>cipher</b> using key <b>key</b> and IV <b>iv</b>. <b>enc</b> should be set to 1 for encryption and zero for decryption.</p> <p>When reading from an encryption BIO the final block is automatically decrypted and checked when EOF is detected. BIO_get_cipher_status() is a BIO_ctrl() macro which can be called to determine whether the decryption operation was successful.</p> <p>BIO_get_cipher_ctx() is a BIO_ctrl() macro which retrieves the internal BIO cipher context. The retrieved context can be used in conjunction with the standard cipher routines to set it up. This is useful when BIO_set_cipher() is not flexible enough for the applications needs.</p> <h1 id="NOTES">NOTES</h1> <p>When encrypting BIO_flush() <b>must</b> be called to flush the final block through the BIO. If it is not then the final block will fail a subsequent decrypt.</p> <p>When decrypting an error on the final block is signaled by a zero return value from the read operation. A successful decrypt followed by EOF will also return zero for the final read. BIO_get_cipher_status() should be called to determine if the decrypt was successful.</p> <p>As always, if BIO_gets() or BIO_puts() support is needed then it can be achieved by preceding the cipher BIO with a buffering BIO.</p> <h1 id="RETURN-VALUES">RETURN VALUES</h1> <p>BIO_f_cipher() returns the cipher BIO method.</p> <p>BIO_set_cipher() does not return a value.</p> <p>BIO_get_cipher_status() returns 1 for a successful decrypt and 0 for failure.</p> <p>BIO_get_cipher_ctx() currently always returns 1.</p> <h1 id="COPYRIGHT">COPYRIGHT</h1> <p>Copyright 2000-2016 The OpenSSL Project Authors. All Rights Reserved.</p> <p>Licensed under the OpenSSL license (the "License"). You may not use this file except in compliance with the License. You can obtain a copy in the file LICENSE in the source distribution or at <a href="https://www.openssl.org/source/license.html">https://www.openssl.org/source/license.html</a>.</p> </body> </html>