*nix Documentation Project
·  Home
 +   man pages
·  Linux HOWTOs
·  FreeBSD Tips
·  *niX Forums

  man pages->NetBSD man pages -> BIO_f_cipher (3)              



NAME    [Toc]    [Back]

       BIO_f_cipher, BIO_set_cipher, BIO_get_cipher_status,
       BIO_get_cipher_ctx - cipher BIO filter

LIBRARY    [Toc]    [Back]

       libcrypto, -lcrypto

SYNOPSIS    [Toc]    [Back]

        #include <openssl/bio.h>
        #include <openssl/evp.h>

        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)

DESCRIPTION    [Toc]    [Back]

       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().

       Cipher BIOs do not support BIO_gets() or BIO_puts().

       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.

       BIO_set_cipher() sets the cipher of BIO <b> to cipher
       using key key and IV iv. enc should be set to 1 for
       encryption and zero for decryption.

       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

       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.

NOTES    [Toc]    [Back]

       When encrypting BIO_flush() must be called to flush the
       final block through the BIO. If it is not then the final
       block will fail a subsequent decrypt.

       When decrypting an error on the final block is signalled
       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.

       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.

RETURN VALUES    [Toc]    [Back]

       BIO_f_cipher() returns the cipher BIO method.

       BIO_set_cipher() does not return a value.

       BIO_get_cipher_status() returns 1 for a successful decrypt
       and 0 for failure.

       BIO_get_cipher_ctx() currently always returns 1.

EXAMPLES    [Toc]    [Back]


SEE ALSO    [Toc]    [Back]


2001-04-12                    0.9.6g              BIO_f_cipher(3)
[ Back ]
 Similar pages
Name OS Title
ipfstat FreeBSD reports on packet filter statistics and filter list
EVP_CIPHER_CTX_get_app_data Tru64 EVP cipher routines
EVP_CIPHER_CTX_flags Tru64 EVP cipher routines
EVP_CIPHER_CTX_ctrl Tru64 EVP cipher routines
EVP_CIPHER_CTX_iv_length Tru64 EVP cipher routines
EVP_CIPHER_CTX_cleanup Tru64 EVP cipher routines
EVP_CIPHER_CTX_cipher Tru64 EVP cipher routines
EVP_CIPHER_CTX_block_size Tru64 EVP cipher routines
EVP_CIPHER_nid Tru64 EVP cipher routines
EVP_CIPHER_CTX_key_length Tru64 EVP cipher routines
Copyright © 2004-2005 DeniX Solutions SRL
newsletter delivery service