ENCRYPT(2)							System Calls Manual							ENCRYPT(2)

NAME

       encrypt, decrypt, netcrypt - DES encryption

SYNOPSIS

       #include <u.h>
       #include <libc.h>

       int  encrypt(void *key, void *data, int len)

       int  decrypt(void *key, void *data, int len)

       int  netcrypt(void *key, void *data)

DESCRIPTION

       Encrypt	and  decrypt  perform DES encryption and decryption.  Key is an array of DESKEYLEN (defined as 7 in <auth.h>) bytes containing the
       encryption key.	Data is an array of len bytes; it must be at least 8 bytes long.  The bytes are encrypted or decrypted in place.

       The DES algorithm encrypts an individual 8 byte block of data.  Encrypt uses the following method to encrypt data longer than 8 bytes.  The
       first 8 bytes are encrypted as usual.  The last byte of the encrypted result is prefixed to the next 7 unencrypted bytes to make the next 8
       bytes to encrypt.  This is repeated until fewer than 7 bytes remain unencrypted.  Any remaining unencrypted bytes are encrypted with enough
       of the preceding encrypted bytes to make a full 8 byte block.  Decrypt uses the inverse algorithm.

       Netcrypt  performs  the	same encryption as a SecureNet Key.  Data points to an ASCII string of decimal digits with numeric value between 0
       and 10000.  These digits are copied into an 8 byte buffer with trailing binary zero fill and encrypted as one DES block.   The  first  four
       bytes are each formatted as two digit ASCII hexadecimal numbers, and the string is copied into data.

SOURCE

       /sys/src/libc/port

DIAGNOSTICS

       These routines return 1 if the data was encrypted, and 0 if the encryption fails.  Encrypt and decrypt fail if the data passed is less than
       8 bytes long.  Netcrypt can fail if it is passed invalid data.

SEE ALSO

       securenet(8)

BUGS

       The source is not included in public distributions.  The implementation is broken in a way  that  makes	it  unsuitable	for  anything  but
       authentication.

																	ENCRYPT(2)