#include <stdio.h>

#define ROTORSIZ        256
#define MASK            0377
#define EMPTY           07777
#define X_SIZE          4099

char    *strrchr();

unsigned        r1[ROTORSIZ];
unsigned        r2[ROTORSIZ];
unsigned        r3[ROTORSIZ];

unsigned char   x[X_SIZE];

init(password, decrypt)
char    *password;
int     decrypt;
{
        register int    index;
        register int    i;
        int             pipe_fd[2];
        unsigned        random;
        long            seed = 123L;
        char            buf[13];

        strncpy(buf, password, 8);
        while (*password) *password++ = '\0';
        buf[8] = buf[0];
        buf[9] = buf[1];

        pipe(pipe_fd);

        if (fork() == 0)
        {
                close(0);
                close(1);
                dup(pipe_fd[0]);
                dup(pipe_fd[1]);
                execl("/usr/lib/makekey", "-", 0);
                execl("/lib/makekey", "-", 0);
                exit(1);
        }

        write(pipe_fd[1], buf, 10);
        wait((int *) NULL);

        if (read(pipe_fd[0], buf, 13) != 13)
        {
                fprintf(stderr, "crypt: cannot generate key\n");
                exit(1);
        }

        for (i = 0 ; i < ROTORSIZ; i++) r1[i] = r2[i] = r3[i] = EMPTY;

        for (i = 2; i < 13; i++) seed = seed * buf[i] + i;

        i = 0;
        while (i < ROTORSIZ)
        {
                seed = (long)(5L * seed + (long)i);
                random = (unsigned)(seed % 65521L);
                index = (int)(random & MASK);
                if (r1[index] == EMPTY)
                        r1[index] = i++;
                else
                        continue;
        }

        i = 0;
        while (i < ROTORSIZ)
        {
                seed = (long)(5L * seed + (long)i);
                random = (unsigned)(seed % 65521L);
                index = (int)(random & MASK);
                if (r2[index] == EMPTY)
                        r2[index] = i++;
                else
                        continue;
        }

        i = 0;
        while (i < ROTORSIZ)
        {
                seed = (long)(5L * seed + (long)i);
                random = (unsigned)(seed % 65521L);
                index = (int)(random & MASK);
                if (r3[index] == EMPTY)
                        r3[index] = i++;
                else
                        continue;
        }

        for (i = 0; i < X_SIZE; i++)
        {
                seed = (long)(5L * seed + (long)i);
                random = (unsigned)(seed % 65521L);
                x[i] = random & 03;
        }

        if (decrypt)
        {
                invert(r1);
                invert(r2);
                invert(r3);
        }
}

invert(r)
unsigned r[ROTORSIZ];
{
        unsigned        t[ROTORSIZ];
        register int    i;

        for (i = 0; i < ROTORSIZ; i++) t[i] = r[i];
        for (i = 0; i < ROTORSIZ; i++) r[t[i]] = i;
}

crypt()
{
        register        int             ch;
        register        int             i    = 0;
        register        unsigned        ofs1 = 0;
        register        unsigned        ofs2 = 0;
        register        unsigned        ofs3 = 0;

        while ((ch = getchar()) != EOF)
        {
                putchar(r3[r2[r1[ch+ofs1&MASK]+ofs2&MASK]+ofs3&MASK]);

                switch (x[i]){
                case 00:
                                ofs1 = ++ofs1 & MASK;
                                break;
                case 01:
                                ofs2 = ++ofs2 & MASK;
                                break;
                case 02:
                                ofs3 = ++ofs3 & MASK;
                                break;
                }

                if (ofs1 == 0) ofs2 = ++ofs2 & MASK;
                if (ofs2 == 0) ofs3 = ++ofs3 & MASK;

                if (++i == X_SIZE) i = 0;
        }
}

decrypt()
{
        register        int             ch;
        register        int             i    = 0;
        register        unsigned        ofs1 = 0;
        register        unsigned        ofs2 = 0;
        register        unsigned        ofs3 = 0;

        while ((ch = getchar()) != EOF)
        {
                putchar(r1[r2[r3[ch]-ofs3&MASK]-ofs2&MASK]-ofs1&MASK);

                switch (x[i]){
                case 00:
                                ofs1 = ++ofs1 & MASK;
                                break;
                case 01:
                                ofs2 = ++ofs2 & MASK;
                                break;
                case 02:
                                ofs3 = ++ofs3 & MASK;
                                break;
                }

                if (ofs1 == 0) ofs2 = ++ofs2 & MASK;
                if (ofs2 == 0) ofs3 = ++ofs3 & MASK;

                if (++i == X_SIZE) i = 0;
        }
}

main(argc, argv)
int     argc;
char    *argv[];
{
        int     flag;
        char    *p;

        p = strrchr(argv[0], '/');

        if (p == NULL) p = argv[0];
        else ++p;

        if (strcmp(p, "crypt") == 0) flag = 0;
        else                               flag = 1;

        if (argc != 2)
                init(getpass("Enter key: "), flag);
        else
                init(argv[1], flag);

        if (flag) decrypt();
        else      crypt();
}