ENCRYPT(2) 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)
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ENCRYPT(2) ENCRYPT(2)
BUGS
The implementation is broken in a way that makes it unsuit-
able for anything but authentication.
Page 2 Plan 9 (printed 11/18/24)