BIO_f_cipher(3) - NetBSD Manual Pages

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BIO_f_cipher(3)              OpenSSL              BIO_f_cipher(3)



NAME

       BIO_f_cipher, BIO_set_cipher, BIO_get_cipher_status,
       BIO_get_cipher_ctx - cipher BIO filter


LIBRARY

       libcrypto, -lcrypto


SYNOPSIS

        #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

       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
       successful.

       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

       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



2001-04-12                    0.9.6g                            1





BIO_f_cipher(3)              OpenSSL              BIO_f_cipher(3)


       by a zero return value from the read operation. A success-
       ful 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

       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

       TBA


SEE ALSO

       TBA

































2001-04-12                    0.9.6g                            2