/* $OpenBSD: crypt.c,v 1.14 2001/06/27 00:58:53 lebel Exp $ */ /* * FreeSec: libcrypt * * Copyright (c) 1994 David Burren * All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * 4. Neither the name of the author nor the names of other contributors * may be used to endorse or promote products derived from this software * without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. * * * This is an original implementation of the DES and the crypt(3) interfaces * by David Burren . * * An excellent reference on the underlying algorithm (and related * algorithms) is: * * B. Schneier, Applied Cryptography: protocols, algorithms, * and source code in C, John Wiley & Sons, 1994. * * Note that in that book's description of DES the lookups for the initial, * pbox, and final permutations are inverted (this has been brought to the * attention of the author). A list of errata for this book has been * posted to the sci.crypt newsgroup by the author and is available for FTP. * * NOTE: * This file has a static version of des_setkey() so that crypt.o exports * only the crypt() interface. This is required to make binaries linked * against crypt.o exportable or re-exportable from the USA. */ #if defined(LIBC_SCCS) && !defined(lint) static char rcsid[] = "$OpenBSD: crypt.c,v 1.14 2001/06/27 00:58:53 lebel Exp $"; #endif /* LIBC_SCCS and not lint */ #include #include #include #include #ifdef DEBUG # include #endif static u_char IP[64] = { 58, 50, 42, 34, 26, 18, 10, 2, 60, 52, 44, 36, 28, 20, 12, 4, 62, 54, 46, 38, 30, 22, 14, 6, 64, 56, 48, 40, 32, 24, 16, 8, 57, 49, 41, 33, 25, 17, 9, 1, 59, 51, 43, 35, 27, 19, 11, 3, 61, 53, 45, 37, 29, 21, 13, 5, 63, 55, 47, 39, 31, 23, 15, 7 }; static u_char inv_key_perm[64]; static u_char u_key_perm[56]; static u_char key_perm[56] = { 57, 49, 41, 33, 25, 17, 9, 1, 58, 50, 42, 34, 26, 18, 10, 2, 59, 51, 43, 35, 27, 19, 11, 3, 60, 52, 44, 36, 63, 55, 47, 39, 31, 23, 15, 7, 62, 54, 46, 38, 30, 22, 14, 6, 61, 53, 45, 37, 29, 21, 13, 5, 28, 20, 12, 4 }; static u_char key_shifts[16] = { 1, 1, 2, 2, 2, 2, 2, 2, 1, 2, 2, 2, 2, 2, 2, 1 }; static u_char inv_comp_perm[56]; static u_char comp_perm[48] = { 14, 17, 11, 24, 1, 5, 3, 28, 15, 6, 21, 10, 23, 19, 12, 4, 26, 8, 16, 7, 27, 20, 13, 2, 41, 52, 31, 37, 47, 55, 30, 40, 51, 45, 33, 48, 44, 49, 39, 56, 34, 53, 46, 42, 50, 36, 29, 32 }; /* * No E box is used, as it's replaced by some ANDs, shifts, and ORs. */ static u_char u_sbox[8][64]; static u_char sbox[8][64] = { { 14, 4, 13, 1, 2, 15, 11, 8, 3, 10, 6, 12, 5, 9, 0, 7, 0, 15, 7, 4, 14, 2, 13, 1, 10, 6, 12, 11, 9, 5, 3, 8, 4, 1, 14, 8, 13, 6, 2, 11, 15, 12, 9, 7, 3, 10, 5, 0, 15, 12, 8, 2, 4, 9, 1, 7, 5, 11, 3, 14, 10, 0, 6, 13 }, { 15, 1, 8, 14, 6, 11, 3, 4, 9, 7, 2, 13, 12, 0, 5, 10, 3, 13, 4, 7, 15, 2, 8, 14, 12, 0, 1, 10, 6, 9, 11, 5, 0, 14, 7, 11, 10, 4, 13, 1, 5, 8, 12, 6, 9, 3, 2, 15, 13, 8, 10, 1, 3, 15, 4, 2, 11, 6, 7, 12, 0, 5, 14, 9 }, { 10, 0, 9, 14, 6, 3, 15, 5, 1, 13, 12, 7, 11, 4, 2, 8, 13, 7, 0, 9, 3, 4, 6, 10, 2, 8, 5, 14, 12, 11, 15, 1, 13, 6, 4, 9, 8, 15, 3, 0, 11, 1, 2, 12, 5, 10, 14, 7, 1, 10, 13, 0, 6, 9, 8, 7, 4, 15, 14, 3, 11, 5, 2, 12 }, { 7, 13, 14, 3, 0, 6, 9, 10, 1, 2, 8, 5, 11, 12, 4, 15, 13, 8, 11, 5, 6, 15, 0, 3, 4, 7, 2, 12, 1, 10, 14, 9, 10, 6, 9, 0, 12, 11, 7, 13, 15, 1, 3, 14, 5, 2, 8, 4, 3, 15, 0, 6, 10, 1, 13, 8, 9, 4, 5, 11, 12, 7, 2, 14 }, { 2, 12, 4, 1, 7, 10, 11, 6, 8, 5, 3, 15, 13, 0, 14, 9, 14, 11, 2, 12, 4, 7, 13, 1, 5, 0, 15, 10, 3, 9, 8, 6, 4, 2, 1, 11, 10, 13, 7, 8, 15, 9, 12, 5, 6, 3, 0, 14, 11, 8, 12, 7, 1, 14, 2, 13, 6, 15, 0, 9, 10, 4, 5, 3 }, { 12, 1, 10, 15, 9, 2, 6, 8, 0, 13, 3, 4, 14, 7, 5, 11, 10, 15, 4, 2, 7, 12, 9, 5, 6, 1, 13, 14, 0, 11, 3, 8, 9, 14, 15, 5, 2, 8, 12, 3, 7, 0, 4, 10, 1, 13, 11, 6, 4, 3, 2, 12, 9, 5, 15, 10, 11, 14, 1, 7, 6, 0, 8, 13 }, { 4, 11, 2, 14, 15, 0, 8, 13, 3, 12, 9, 7, 5, 10, 6, 1, 13, 0, 11, 7, 4, 9, 1, 10, 14, 3, 5, 12, 2, 15, 8, 6, 1, 4, 11, 13, 12, 3, 7, 14, 10, 15, 6, 8, 0, 5, 9, 2, 6, 11, 13, 8, 1, 4, 10, 7, 9, 5, 0, 15, 14, 2, 3, 12 }, { 13, 2, 8, 4, 6, 15, 11, 1, 10, 9, 3, 14, 5, 0, 12, 7, 1, 15, 13, 8, 10, 3, 7, 4, 12, 5, 6, 11, 0, 14, 9, 2, 7, 11, 4, 1, 9, 12, 14, 2, 0, 6, 10, 13, 15, 3, 5, 8, 2, 1, 14, 7, 4, 10, 8, 13, 15, 12, 9, 0, 3, 5, 6, 11 } }; static u_char un_pbox[32]; static u_char pbox[32] = { 16, 7, 20, 21, 29, 12, 28, 17, 1, 15, 23, 26, 5, 18, 31, 10, 2, 8, 24, 14, 32, 27, 3, 9, 19, 13, 30, 6, 22, 11, 4, 25 }; static u_int32_t bits32[32] = { 0x80000000, 0x40000000, 0x20000000, 0x10000000, 0x08000000, 0x04000000, 0x02000000, 0x01000000, 0x00800000, 0x00400000, 0x00200000, 0x00100000, 0x00080000, 0x00040000, 0x00020000, 0x00010000, 0x00008000, 0x00004000, 0x00002000, 0x00001000, 0x00000800, 0x00000400, 0x00000200, 0x00000100, 0x00000080, 0x00000040, 0x00000020, 0x00000010, 0x00000008, 0x00000004, 0x00000002, 0x00000001 }; static u_char bits8[8] = { 0x80, 0x40, 0x20, 0x10, 0x08, 0x04, 0x02, 0x01 }; static u_int32_t saltbits; static int32_t old_salt; static u_int32_t *bits28, *bits24; static u_char init_perm[64], final_perm[64]; static u_int32_t en_keysl[16], en_keysr[16]; static u_int32_t de_keysl[16], de_keysr[16]; static int des_initialised = 0; static u_char m_sbox[4][4096]; static u_int32_t psbox[4][256]; static u_int32_t ip_maskl[8][256], ip_maskr[8][256]; static u_int32_t fp_maskl[8][256], fp_maskr[8][256]; static u_int32_t key_perm_maskl[8][128], key_perm_maskr[8][128]; static u_int32_t comp_maskl[8][128], comp_maskr[8][128]; static u_int32_t old_rawkey0, old_rawkey1; static u_char ascii64[] = "./0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz"; /* 0000000000111111111122222222223333333333444444444455555555556666 */ /* 0123456789012345678901234567890123456789012345678901234567890123 */ static __inline int ascii_to_bin(ch) char ch; { if (ch > 'z') return(0); if (ch >= 'a') return(ch - 'a' + 38); if (ch > 'Z') return(0); if (ch >= 'A') return(ch - 'A' + 12); if (ch > '9') return(0); if (ch >= '.') return(ch - '.'); return(0); } static void des_init() { int i, j, b, k, inbit, obit; u_int32_t *p, *il, *ir, *fl, *fr; old_rawkey0 = old_rawkey1 = 0; saltbits = 0; old_salt = 0; bits24 = (bits28 = bits32 + 4) + 4; /* * Invert the S-boxes, reordering the input bits. */ for (i = 0; i < 8; i++) for (j = 0; j < 64; j++) { b = (j & 0x20) | ((j & 1) << 4) | ((j >> 1) & 0xf); u_sbox[i][j] = sbox[i][b]; } /* * Convert the inverted S-boxes into 4 arrays of 8 bits. * Each will handle 12 bits of the S-box input. */ for (b = 0; b < 4; b++) for (i = 0; i < 64; i++) for (j = 0; j < 64; j++) m_sbox[b][(i << 6) | j] = (u_sbox[(b << 1)][i] << 4) | u_sbox[(b << 1) + 1][j]; /* * Set up the initial & final permutations into a useful form, and * initialise the inverted key permutation. */ for (i = 0; i < 64; i++) { init_perm[final_perm[i] = IP[i] - 1] = i; inv_key_perm[i] = 255; } /* * Invert the key permutation and initialise the inverted key * compression permutation. */ for (i = 0; i < 56; i++) { u_key_perm[i] = key_perm[i] - 1; inv_key_perm[key_perm[i] - 1] = i; inv_comp_perm[i] = 255; } /* * Invert the key compression permutation. */ for (i = 0; i < 48; i++) { inv_comp_perm[comp_perm[i] - 1] = i; } /* * Set up the OR-mask arrays for the initial and final permutations, * and for the key initial and compression permutations. */ for (k = 0; k < 8; k++) { for (i = 0; i < 256; i++) { *(il = &ip_maskl[k][i]) = 0; *(ir = &ip_maskr[k][i]) = 0; *(fl = &fp_maskl[k][i]) = 0; *(fr = &fp_maskr[k][i]) = 0; for (j = 0; j < 8; j++) { inbit = 8 * k + j; if (i & bits8[j]) { if ((obit = init_perm[inbit]) < 32) *il |= bits32[obit]; else *ir |= bits32[obit-32]; if ((obit = final_perm[inbit]) < 32) *fl |= bits32[obit]; else *fr |= bits32[obit - 32]; } } } for (i = 0; i < 128; i++) { *(il = &key_perm_maskl[k][i]) = 0; *(ir = &key_perm_maskr[k][i]) = 0; for (j = 0; j < 7; j++) { inbit = 8 * k + j; if (i & bits8[j + 1]) { if ((obit = inv_key_perm[inbit]) == 255) continue; if (obit < 28) *il |= bits28[obit]; else *ir |= bits28[obit - 28]; } } *(il = &comp_maskl[k][i]) = 0; *(ir = &comp_maskr[k][i]) = 0; for (j = 0; j < 7; j++) { inbit = 7 * k + j; if (i & bits8[j + 1]) { if ((obit=inv_comp_perm[inbit]) == 255) continue; if (obit < 24) *il |= bits24[obit]; else *ir |= bits24[obit - 24]; } } } } /* * Invert the P-box permutation, and convert into OR-masks for * handling the output of the S-box arrays setup above. */ for (i = 0; i < 32; i++) un_pbox[pbox[i] - 1] = i; for (b = 0; b < 4; b++) for (i = 0; i < 256; i++) { *(p = &psbox[b][i]) = 0; for (j = 0; j < 8; j++) { if (i & bits8[j]) *p |= bits32[un_pbox[8 * b + j]]; } } des_initialised = 1; } static void setup_salt(salt) int32_t salt; { u_int32_t obit, saltbit; int i; if (salt == old_salt) return; old_salt = salt; saltbits = 0; saltbit = 1; obit = 0x800000; for (i = 0; i < 24; i++) { if (salt & saltbit) saltbits |= obit; saltbit <<= 1; obit >>= 1; } } static int des_setkey(key) const char *key; { u_int32_t k0, k1, rawkey0, rawkey1; int shifts, round; if (!des_initialised) des_init(); rawkey0 = ntohl(*(u_int32_t *) key); rawkey1 = ntohl(*(u_int32_t *) (key + 4)); if ((rawkey0 | rawkey1) && rawkey0 == old_rawkey0 && rawkey1 == old_rawkey1) { /* * Already setup for this key. * This optimisation fails on a zero key (which is weak and * has bad parity anyway) in order to simplify the starting * conditions. */ return(0); } old_rawkey0 = rawkey0; old_rawkey1 = rawkey1; /* * Do key permutation and split into two 28-bit subkeys. */ k0 = key_perm_maskl[0][rawkey0 >> 25] | key_perm_maskl[1][(rawkey0 >> 17) & 0x7f] | key_perm_maskl[2][(rawkey0 >> 9) & 0x7f] | key_perm_maskl[3][(rawkey0 >> 1) & 0x7f] | key_perm_maskl[4][rawkey1 >> 25] | key_perm_maskl[5][(rawkey1 >> 17) & 0x7f] | key_perm_maskl[6][(rawkey1 >> 9) & 0x7f] | key_perm_maskl[7][(rawkey1 >> 1) & 0x7f]; k1 = key_perm_maskr[0][rawkey0 >> 25] | key_perm_maskr[1][(rawkey0 >> 17) & 0x7f] | key_perm_maskr[2][(rawkey0 >> 9) & 0x7f] | key_perm_maskr[3][(rawkey0 >> 1) & 0x7f] | key_perm_maskr[4][rawkey1 >> 25] | key_perm_maskr[5][(rawkey1 >> 17) & 0x7f] | key_perm_maskr[6][(rawkey1 >> 9) & 0x7f] | key_perm_maskr[7][(rawkey1 >> 1) & 0x7f]; /* * Rotate subkeys and do compression permutation. */ shifts = 0; for (round = 0; round < 16; round++) { u_int32_t t0, t1; shifts += key_shifts[round]; t0 = (k0 << shifts) | (k0 >> (28 - shifts)); t1 = (k1 << shifts) | (k1 >> (28 - shifts)); de_keysl[15 - round] = en_keysl[round] = comp_maskl[0][(t0 >> 21) & 0x7f] | comp_maskl[1][(t0 >> 14) & 0x7f] | comp_maskl[2][(t0 >> 7) & 0x7f] | comp_maskl[3][t0 & 0x7f] | comp_maskl[4][(t1 >> 21) & 0x7f] | comp_maskl[5][(t1 >> 14) & 0x7f] | comp_maskl[6][(t1 >> 7) & 0x7f] | comp_maskl[7][t1 & 0x7f]; de_keysr[15 - round] = en_keysr[round] = comp_maskr[0][(t0 >> 21) & 0x7f] | comp_maskr[1][(t0 >> 14) & 0x7f] | comp_maskr[2][(t0 >> 7) & 0x7f] | comp_maskr[3][t0 & 0x7f] | comp_maskr[4][(t1 >> 21) & 0x7f] | comp_maskr[5][(t1 >> 14) & 0x7f] | comp_maskr[6][(t1 >> 7) & 0x7f] | comp_maskr[7][t1 & 0x7f]; } return(0); } static int do_des(l_in, r_in, l_out, r_out, count) u_int32_t l_in, r_in, *l_out, *r_out; int count; { /* * l_in, r_in, l_out, and r_out are in pseudo-"big-endian" format. */ u_int32_t l, r, *kl, *kr, *kl1, *kr1; u_int32_t f, r48l, r48r; int round; if (count == 0) { return(1); } else if (count > 0) { /* * Encrypting */ kl1 = en_keysl; kr1 = en_keysr; } else { /* * Decrypting */ count = -count; kl1 = de_keysl; kr1 = de_keysr; } /* * Do initial permutation (IP). */ l = ip_maskl[0][l_in >> 24] | ip_maskl[1][(l_in >> 16) & 0xff] | ip_maskl[2][(l_in >> 8) & 0xff] | ip_maskl[3][l_in & 0xff] | ip_maskl[4][r_in >> 24] | ip_maskl[5][(r_in >> 16) & 0xff] | ip_maskl[6][(r_in >> 8) & 0xff] | ip_maskl[7][r_in & 0xff]; r = ip_maskr[0][l_in >> 24] | ip_maskr[1][(l_in >> 16) & 0xff] | ip_maskr[2][(l_in >> 8) & 0xff] | ip_maskr[3][l_in & 0xff] | ip_maskr[4][r_in >> 24] | ip_maskr[5][(r_in >> 16) & 0xff] | ip_maskr[6][(r_in >> 8) & 0xff] | ip_maskr[7][r_in & 0xff]; while (count--) { /* * Do each round. */ kl = kl1; kr = kr1; round = 16; while (round--) { /* * Expand R to 48 bits (simulate the E-box). */ r48l = ((r & 0x00000001) << 23) | ((r & 0xf8000000) >> 9) | ((r & 0x1f800000) >> 11) | ((r & 0x01f80000) >> 13) | ((r & 0x001f8000) >> 15); r48r = ((r & 0x0001f800) << 7) | ((r & 0x00001f80) << 5) | ((r & 0x000001f8) << 3) | ((r & 0x0000001f) << 1) | ((r & 0x80000000) >> 31); /* * Do salting for crypt() and friends, and * XOR with the permuted key. */ f = (r48l ^ r48r) & saltbits; r48l ^= f ^ *kl++; r48r ^= f ^ *kr++; /* * Do sbox lookups (which shrink it back to 32 bits) * and do the pbox permutation at the same time. */ f = psbox[0][m_sbox[0][r48l >> 12]] | psbox[1][m_sbox[1][r48l & 0xfff]] | psbox[2][m_sbox[2][r48r >> 12]] | psbox[3][m_sbox[3][r48r & 0xfff]]; /* * Now that we've permuted things, complete f(). */ f ^= l; l = r; r = f; } r = l; l = f; } /* * Do final permutation (inverse of IP). */ *l_out = fp_maskl[0][l >> 24] | fp_maskl[1][(l >> 16) & 0xff] | fp_maskl[2][(l >> 8) & 0xff] | fp_maskl[3][l & 0xff] | fp_maskl[4][r >> 24] | fp_maskl[5][(r >> 16) & 0xff] | fp_maskl[6][(r >> 8) & 0xff] | fp_maskl[7][r & 0xff]; *r_out = fp_maskr[0][l >> 24] | fp_maskr[1][(l >> 16) & 0xff] | fp_maskr[2][(l >> 8) & 0xff] | fp_maskr[3][l & 0xff] | fp_maskr[4][r >> 24] | fp_maskr[5][(r >> 16) & 0xff] | fp_maskr[6][(r >> 8) & 0xff] | fp_maskr[7][r & 0xff]; return(0); } static int des_cipher(in, out, salt, count) const char *in; char *out; int32_t salt; int count; { u_int32_t l_out, r_out, rawl, rawr; u_int32_t x[2]; int retval; if (!des_initialised) des_init(); setup_salt(salt); memcpy(x, in, sizeof x); rawl = ntohl(x[0]); rawr = ntohl(x[1]); retval = do_des(rawl, rawr, &l_out, &r_out, count); x[0] = htonl(l_out); x[1] = htonl(r_out); memcpy(out, x, sizeof x); return(retval); } char * crypt(key, setting) const char *key; const char *setting; { int i; u_int32_t count, salt, l, r0, r1, keybuf[2]; u_char *p, *q; static u_char output[21]; extern char *md5crypt __P((const char *, const char *)); extern char *bcrypt __P((const char *, const char *)); if (setting[0] == '$') { switch (setting[1]) { case '1': return (md5crypt(key, setting)); default: return bcrypt(key, setting); } } if (!des_initialised) des_init(); /* * Copy the key, shifting each character up by one bit * and padding with zeros. */ q = (u_char *) keybuf; while ((q - (u_char *) keybuf) < sizeof(keybuf)) { if ((*q++ = *key << 1)) key++; } if (des_setkey((u_char *) keybuf)) return(NULL); if (*setting == _PASSWORD_EFMT1) { /* * "new"-style: * setting - underscore, 4 bytes of count, 4 bytes of salt * key - unlimited characters */ for (i = 1, count = 0; i < 5; i++) count |= ascii_to_bin(setting[i]) << (i - 1) * 6; for (i = 5, salt = 0; i < 9; i++) salt |= ascii_to_bin(setting[i]) << (i - 5) * 6; while (*key) { /* * Encrypt the key with itself. */ if (des_cipher((u_char*)keybuf, (u_char*)keybuf, 0, 1)) return(NULL); /* * And XOR with the next 8 characters of the key. */ q = (u_char *) keybuf; while (((q - (u_char *) keybuf) < sizeof(keybuf)) && *key) *q++ ^= *key++ << 1; if (des_setkey((u_char *) keybuf)) return(NULL); } strlcpy((char *)output, setting, 10); /* * Double check that we weren't given a short setting. * If we were, the above code will probably have created * wierd values for count and salt, but we don't really care. * Just make sure the output string doesn't have an extra * NUL in it. */ p = output + strlen((const char *)output); } else { /* * "old"-style: * setting - 2 bytes of salt * key - up to 8 characters */ count = 25; salt = (ascii_to_bin(setting[1]) << 6) | ascii_to_bin(setting[0]); output[0] = setting[0]; /* * If the encrypted password that the salt was extracted from * is only 1 character long, the salt will be corrupted. We * need to ensure that the output string doesn't have an extra * NUL in it! */ output[1] = setting[1] ? setting[1] : output[0]; p = output + 2; } setup_salt(salt); /* * Do it. */ if (do_des(0, 0, &r0, &r1, count)) return(NULL); /* * Now encode the result... */ l = (r0 >> 8); *p++ = ascii64[(l >> 18) & 0x3f]; *p++ = ascii64[(l >> 12) & 0x3f]; *p++ = ascii64[(l >> 6) & 0x3f]; *p++ = ascii64[l & 0x3f]; l = (r0 << 16) | ((r1 >> 16) & 0xffff); *p++ = ascii64[(l >> 18) & 0x3f]; *p++ = ascii64[(l >> 12) & 0x3f]; *p++ = ascii64[(l >> 6) & 0x3f]; *p++ = ascii64[l & 0x3f]; l = r1 << 2; *p++ = ascii64[(l >> 12) & 0x3f]; *p++ = ascii64[(l >> 6) & 0x3f]; *p++ = ascii64[l & 0x3f]; *p = 0; return((char *)output); }