ref: 4d919ab612f61c1ef1b21d41513f264d57c010d4
dir: /sys/src/libc/port/crypt.c/
/* * Data Encryption Standard * D.P.Mitchell 83/06/08. * * block_cipher(key, block, decrypting) * * these routines use the non-standard 7 byte format * for DES keys. */ #include <u.h> #include <libc.h> #include <libsec.h> /* * destructively encrypt the buffer, which * must be at least 8 characters long. */ int encrypt(void *key, void *vbuf, int n) { ulong ekey[32]; uchar *buf; int i, r; if(n < 8) return 0; key_setup(key, ekey); buf = vbuf; n--; r = n % 7; n /= 7; for(i = 0; i < n; i++){ block_cipher(ekey, buf, 0); buf += 7; } if(r) block_cipher(ekey, buf - 7 + r, 0); return 1; } /* * destructively decrypt the buffer, which * must be at least 8 characters long. */ int decrypt(void *key, void *vbuf, int n) { ulong ekey[128]; uchar *buf; int i, r; if(n < 8) return 0; key_setup(key, ekey); buf = vbuf; n--; r = n % 7; n /= 7; buf += n * 7; if(r) block_cipher(ekey, buf - 7 + r, 1); for(i = 0; i < n; i++){ buf -= 7; block_cipher(ekey, buf, 1); } return 1; }