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/* |
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* "enigma.c" is in file cbw.tar from |
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* anonymous FTP host watmsg.waterloo.edu: pub/crypt/cbw.tar.Z |
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* |
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* A one-rotor machine designed along the lines of Enigma |
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* but considerably trivialized. |
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* |
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* A public-domain replacement for the UNIX "crypt" command. |
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* Changed to fit in mcrypt by nmav@i-net.paiko.gr |
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*/ |
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|
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/* modified in order to use the libmcrypt API by Nikos Mavroyanopoulos |
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* All modifications are placed under the license of libmcrypt. |
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*/ |
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|
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/* $Id: enigma.c,v 1.12 2000/03/19 14:08:34 nikos Exp $ */ |
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|
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#include "libdefs.h" |
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#include "bzero.h" |
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#include "enigma.h" |
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|
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/* it needs to be linked against libufc or libcrypt */ |
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/* it no longer needs that. It just needs the password to be |
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* transformed by unix crypt() or the mhash SCRYPT |
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*/ |
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|
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void _mcrypt_enigma_set_key(CRYPT_KEY *ckey, char* password, int plen) |
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{ |
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int ic, i, k, temp; |
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unsigned random; |
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sword32 seed; |
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|
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|
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Bzero(ckey, sizeof(CRYPT_KEY)); |
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ckey->n1 = ckey->n2 = ckey->nr1 = ckey->nr2 = 0; |
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|
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if (plen > 13) plen = 13; |
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memmove( ckey->cbuf, password, plen); |
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|
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seed = 123; |
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for (i = 0; i < 13; i++) |
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seed = seed * ckey->cbuf[i] + i; |
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for (i = 0; i < ROTORSZ; i++) { |
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ckey->t1[i] = i; |
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ckey->deck[i] = i; |
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} |
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for (i = 0; i < ROTORSZ; i++) { |
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seed = 5 * seed + ckey->cbuf[i % 13]; |
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random = seed % 65521; |
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k = ROTORSZ - 1 - i; |
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ic = (random & MASK) % (k + 1); |
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random >>= 8; |
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|
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temp = ckey->t1[k]; |
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ckey->t1[k] = ckey->t1[ic]; |
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ckey->t1[ic] = temp; |
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if (ckey->t3[k] != 0) |
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continue; |
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|
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ic = (random & MASK) % k; |
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while (ckey->t3[ic] != 0) |
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ic = (ic + 1) % k; |
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ckey->t3[k] = ic; |
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ckey->t3[ic] = k; |
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} |
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|
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for (i = 0; i < ROTORSZ; i++) |
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ckey->t2[ckey->t1[i] & MASK] = i; |
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|
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return; |
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} |
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|
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|
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int shuffle(CRYPT_KEY* ckey) |
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{ |
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int i, ic, k, temp; |
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unsigned random; |
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static sword32 seed = 123; |
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|
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for (i = 0; i < ROTORSZ; i++) { |
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seed = 5 * seed + ckey->cbuf[i % 13]; |
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random = seed % 65521; |
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k = ROTORSZ - 1 - i; |
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ic = (random & MASK) % (k + 1); |
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temp = ckey->deck[k]; |
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ckey->deck[k] = ckey->deck[ic]; |
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ckey->deck[ic] = temp; |
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} |
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return 0; |
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} |
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|
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void _mcrypt_enigma_encrypt(CRYPT_KEY *ckey, void *gtext, int textlen) |
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{ /* 0 or 1 */ |
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int i, j; |
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int secureflg=0; |
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char *text = gtext; |
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|
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for (j = 0; j < textlen; j++) { |
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|
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i = text[j]; |
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if (secureflg) { |
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ckey->nr1 = ckey->deck[ckey->n1] & MASK; |
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ckey->nr2 = ckey->deck[ckey->nr1] & MASK; |
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} else { |
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ckey->nr1 = ckey->n1; |
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} |
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i = ckey->t2[(ckey->t3[(ckey->t1[(i + ckey->nr1) & MASK] + ckey->nr2) & MASK] - ckey->nr2) & MASK] - ckey->nr1; |
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text[j] = i; |
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ckey->n1++; |
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if (ckey->n1 == ROTORSZ) { |
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ckey->n1 = 0; |
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ckey->n2++; |
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if (ckey->n2 == ROTORSZ) |
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ckey->n2 = 0; |
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if (secureflg) { |
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shuffle(ckey); |
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} else { |
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ckey->nr2 = ckey->n2; |
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} |
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} |
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} |
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|
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return; |
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} |
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|
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void _mcrypt_enigma_decrypt(CRYPT_KEY *ckey, void *gtext, int textlen) |
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{ /* 0 or 1 */ |
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int i, j; |
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int secureflg=0; |
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char *text = gtext; |
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|
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|
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for (j = 0; j < textlen; j++) { |
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|
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i = text[j]; |
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if (secureflg) { |
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ckey->nr1 = ckey->deck[ckey->n1] & MASK; |
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ckey->nr2 = ckey->deck[ckey->nr1] & MASK; |
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} else { |
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ckey->nr1 = ckey->n1; |
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} |
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i = ckey->t2[(ckey->t3[(ckey->t1[(i + ckey->nr1) & MASK] + ckey->nr2) & MASK] - ckey->nr2) & MASK] - ckey->nr1; |
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text[j] = i; |
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ckey->n1++; |
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if (ckey->n1 == ROTORSZ) { |
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ckey->n1 = 0; |
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ckey->n2++; |
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if (ckey->n2 == ROTORSZ) |
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ckey->n2 = 0; |
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if (secureflg) { |
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shuffle(ckey); |
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} else { |
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ckey->nr2 = ckey->n2; |
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} |
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} |
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} |
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|
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return; |
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} |
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