8eec1389fb
which is redundant. They are now in their own document. Also, in the name section, all the functions described shoud be enumerated. This will also make it much simpler to generate softlinks name like each function to man-pages containing the info.
76 lines
2.4 KiB
Text
76 lines
2.4 KiB
Text
=pod
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=head1 NAME
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BIO_f_cipher, BIO_set_cipher, BIO_get_cipher_status, BIO_get_cipher_ctx - cipher BIO filter
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=head1 SYNOPSIS
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#include <openssl/bio.h>
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#include <openssl/evp.h>
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BIO_METHOD * BIO_f_cipher(void);
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void BIO_set_cipher(BIO *b,const EVP_CIPHER *cipher,
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unsigned char *key, unsigned char *iv, int enc);
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int BIO_get_cipher_status(BIO *b)
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int BIO_get_cipher_ctx(BIO *b, EVP_CIPHER_CTX **pctx)
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=head1 DESCRIPTION
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BIO_f_cipher() returns the cipher BIO method. This is a filter
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BIO that encrypts any data written through it, and decrypts any data
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read from it. It is a BIO wrapper for the cipher routines
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EVP_CipherInit(), EVP_CipherUpdate() and EVP_CipherFinal().
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Cipher BIOs do not support BIO_gets() or BIO_puts().
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BIO_flush() on an encryption BIO that is being written through is
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used to signal that no more data is to be encrypted: this is used
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to flush and possibly pad the final block through the BIO.
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BIO_set_cipher() sets the cipher of BIO <b> to B<cipher> using key B<key>
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and IV B<iv>. B<enc> should be set to 1 for encryption and zero for
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decryption.
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When reading from an encryption BIO the final block is automatically
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decrypted and checked when EOF is detected. BIO_get_cipher_status()
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is a BIO_ctrl() macro which can be called to determine whether the
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decryption operation was successful.
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BIO_get_cipher_ctx() is a BIO_ctrl() macro which retrieves the internal
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BIO cipher context. The retrieved context can be used in conjustion
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with the standard cipher routines to set it up. This is useful when
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BIO_set_cipher() is not flexible enough for the applications needs.
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=head1 NOTES
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When encrypting BIO_flush() B<must> be called to flush the final block
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through the BIO. If it is not then the final block will fail a subsequent
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decrypt.
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When decrypting an error on the final block is signalled by a zero
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return value from the read operation. A successful decrypt followed
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by EOF will also return zero for the final read. BIO_get_cipher_status()
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should be called to determine if the decrypt was successful.
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As always, if BIO_gets() or BIO_puts() support is needed then it can
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be achieved by preceding the cipher BIO with a buffering BIO.
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=head1 RETURN VALUES
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BIO_f_cipher() returns the cipher BIO method.
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BIO_set_cipher() does not return a value.
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BIO_get_cipher_status() returns 1 for a successful decrypt and 0
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for failure.
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BIO_get_cipher_ctx() currently always returns 1.
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=head1 EXAMPLES
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TBA
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=head1 SEE ALSO
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TBA
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