This Inline C widget will do it. It modifies the passed SV C style if it is suitable for decryption, or ignores it if the magic header is missing. 

use Inline C;

my $password = "hello";
my $file = "c:/enc.txt";

open F, $file or die $!;
my $data = do{ local $/; <F> };
close F;

print "Before:\n$data\n";
decode( $data, $password );
print "After:\n$data\n";

__END__
__C__
typedef unsigned int  ULG;

void decode( SV* str, char *passwd ) 
{
    ULG s,t,v,crc_32_tab[256],keys[3],temp;
    STRLEN rawlen;
    int decrypted = 0;
    char *file, *data;
    char *magic = "VimCrypt~01!\0";
#define ROTOR(a) { \
    keys[0] = CRC32(keys[0], a); keys[1] += keys[0] & 0xff; \
    keys[1] = keys[1] * 134775813L + 1; \
    keys[2] = CRC32(keys[2], (int)(keys[1] >> 24)); \
}
#define CRC32(c, b) (crc_32_tab[((int)(c) ^ (b)) & 0xff] ^ ((c) >> 8))

    file = (char*)SvPV(str, rawlen);
    if ( rawlen == 0 ) return;  /* we got a null string */
    
    while ( *magic != '\0' ) {
        if ( *(magic++) != *(file++) ) return; /* did not find magic h
+eader */
    }
    
    for (t=0; t<256; t++) {
        v = t;
        for (s=0; s<8; s++) v = (v >> 1) ^ ((v & 1) * (ULG)0xedb88320L
+);
        crc_32_tab[t] = v;
    }
    
    keys[0] = 305419896L; keys[1] = 591751049L; keys[2] = 878082192L;
    
    while (*passwd != '\0') ROTOR(*(passwd++));
    
    data = file;
    while( *file != '\0' ) {
        temp = 0xffff & (keys[2] | 2);
        *file ^= (int)(((temp * (temp ^ 1)) >> 8) & 0xff);
        ROTOR(*(file++));
        decrypted++;
    }

    sv_setpvn( str, data, decrypted ); /* modify the passed SV with de
+crypt */
}

[download]

cheers

tachyon

In reply to Re: How to decrypt a file encrypted with vi -x or shell crypt by tachyon
in thread How to decrypt a file encrypted with vi -x or shell crypt by rinceWind

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