As evolution of this old idea, here is new and less dumber alphabetical obfuscator. Any bug reports and ideas how to squeeze its results are welcome.

#! /usr/bin/perl -X

%code = (
    "\t"   => "chr oct ord w",
    "\n"   => "chr hex a",
    ' '    => "chr oct hex ffa",
    '!'    => "chr hex hex hex f",
    '"'    => "chr oct oct hex ceaa",
    '#'    => "chr oct hex abaa",
    '$'    => "chr oct hex afaa",
    '%'    => "chr oct oct hex daaa",
    '&'    => "chr hex oct hex cda",
    "'"    => "chr oct hex baba",
    '('    => "chr hex oct hex daa",
    ')'    => "chr oct hex caaa",
    '*'    => "chr oct hex ceaa",
    '+'    => "chr oct sqrt hex afa",
    ','    => "chr oct sqrt hex baa",
    '-'    => "chr oct hex daaa",
    '.'    => "chr oct hex ddea",
    '/'    => "chr oct sqrt hex cba",
    0      => "oct a",
    1      => "m mm",
    2      => "int log hex a",
    3      => "int sqrt hex a",
    4      => "int log ord a",
    5      => "int log hex aa",
    6      => "chr sqrt hex baa",
    7      => "int log hex aaa",
    8      => "int oct ord l",
    9      => "int oct ord w",
    ':'    => "chr oct oct ord n",
    ';'    => "chr sqrt hex daa",
    '<'    => "chr oct oct ord p",
    '='    => "chr sqrt hex eaa",
    '>'    => "chr oct oct ord r",
    '?'    => "chr sqrt hex faa",
    '@'    => "chr oct ord d",
    '['    => "chr oct oct hex cd",
    "\\"   => "chr oct oct hex ce",
    ']'    => "chr oct oct hex cf",
    '^'    => "chr oct hex hex dfa",
    _      => "chr log sqrt exp hex be",
    '`'    => "chr hex oct oct ord p",
    '{'    => "chr oct hex ad",
    '|'    => "chr oct hex ae",
    '}'    => "chr oct hex af",
    '~'    => "chr oct oct hex ord h",
);

$_ eq eval $code{$_}    or die "Code '$_' (ascii " . ord . ") mismatch
+\n"
    for sort keys %code;

undef $/;
$_ = <>;

while ( /([A-X][a-x]+)        # 1
        |([A-X][A-X]+)        # 2
        |([C-Z][c-z]+)        # 3
        |([C-Z][C-Z]*)        # 4
        |([AB])               # 5
        |([a-y]+)             # 6
        |(z+)                 # 7
        |(.)(\8*)             # 8,9
        /sgx
) {
    $i = lc $+;
    if ($1 || $2 || $3 || $4 and 1 + eval { prototype "CORE::$i" } and
+ !$@
     or length ($4) == 1) {
        $j = $1 || $2 ? "y" : "b";
        $i = "q $j$i$j";
    } 
    if      ($1)        { $s = "s zzucfirst ${i}ze";
    } elsif ($2)        { $s = "s zzuc ${i}ze";
    } elsif ($3)        { $s = "s aaucfirst ${i}ae";
    } elsif ($4)        { $s = "s aauc ${i}ae";
    } elsif ($5)        { $s = "s zzuc q y${i}yze";
    } elsif ($6)        { $s = "s zz${i}z";
    } elsif ($7)        { $s = "s aa${i}a";
    } elsif ($code{$8}) {
        unshift @s, "s zzchr ordze"
            for 1 .. length $9;
        $s = "s zz$code{$8}ze";
    } else {
        die "Unknown symbol '$8'\n";
    }
    unshift @s, $s;
}
$_ = (join " x ", @s[@s/2 + 1 .. $#s], "eval if ")
   . (join " x ", @s[0 .. @s/2]);
s/(.{1,79})( |$)/$1\n/g;
s#(.+)#
    $_ = $1;
    s/^(.{${\(int rand length)}} )/$1 /
        while 79 != length;
    $_
#eg;
print;
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Update 23-APR-02: source slightly modified.