Name
des_decipher
Synopsis
void des_decipher(const unsigned char *ciphertext, unsigned char *plaintext, unsigned char *key);
Return Value
None.
Description
Uses DES to decipher one 64-bit block of ciphertext
specified by ciphertext. It is assumed
that ciphertext contains data
previously enciphered with des_encipher.
Specify the 64-bit key in key. (Recall
that every eighth bit of this key is ignored, resulting in a
56-bit key.) The 64-bit block of plaintext is returned in
plaintext. It is the responsibility of
the caller to manage the storage required in
plaintext. To decipher a large buffer
of data, call des_decipher in accordance with
the block cipher mode used to encipher the data. For efficiency,
des_decipher can reuse the subkeys computed
during a previous call. To enable this, set
key to NULL in subsequent calls.
Complexity
O (1)
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