Re: better than read-hide-char

[Davis Herring <herring@lanl.gov>]

> Sure.  Another option would be the patch below.
> BTW, for those who like to have their password sanity-checked locally
> before they press RET, it even displays some kind of short hash ;-)

Doesn't displaying even 16 bits of any hash of each prefix of the 
password leak those prefixes, each guided by the last?

Here is a lookup table based on the first 12 bits of the MD5 hash of 
each ASCII printing character:

01a #
021 X
03c s
0bc %
0cc a
0d6 C
0fb ]
167 6
21c Z
251 h
26b +
28d \
2db l
336 -
338 *
359 '
363 j
3a3 E
415 y
43e =
44c P
45c 9
4a8 c
4b4 r
4c6 U
4c7 ~
505 .
518 @
520 V
524 <
57c Y
5db S
61e W
666 /
696 M
6cf &
6f8 m
721
769 q
7b7 u
7b8 n
7e6 ^
7fc A
800 F
815 [
827 d
833 `
838 p
84c (
853 :
865 i
8ce k
8d9 N
8f1 7
8fa f
903 !
92e b
937 )
9d5 B
9dd x
9e3 v
9ee ;
a5f K
a87 4
b14 _
b15 "
b2f g
b99 |
b9e T
c0c ,
c1d H
c3e $
c4c 1
c81 2
c9f 8
cbb }
ced >
cfc 0
d14 ?
d20 L
d95 o
dd7 I
dfc G
e16 e
e1e R
e35 t
e4d 5
ecc 3
f09 Q
f12 w
f18 O
f62 D
f95 {
fba z
ff4 J

And, supposing the first hash is c3e... (i.e., the first character is 
$), here's the next table:

033 $2
06d $1
099 $3
0b3 $J
0bf $(
0d5 $e
0f5 $O
115 $@
134 $T
141 $[
172 $4
19c $'
1d0 $%
1dc $|
20c $S
20f $d
213 $=
24d $l
2a0 $p
2a1 $Q
2fb $, or $H
30b $t
359 $.
36a $y
36b $/
39a $Y
3cb $s
3e3 $c
3e4 $D
459 $+
474 $X
481 $-
4f3 $7
52d $a
588 $$
601 $h
620 ${
6b5 $P
6b6 $f
6bf $Z
6c0 $`
71e $C
798 $F
7a4 $I
7d4 $R
7dc $~
867 $K
86c $8
870 $5
872 $x
884 $!
89f $M
926 $>
934 $L
953 $z
993 $:
a09 $k
a0f $&
a16 $i
a3d $v
a7b $j
aa7 $r
ae9 $o
b05 $]
b3e $6
b89 $A or $?
bea $"
c4a $u
c6a $*
c6e $
d0a $0
d38 $U
d3f $w
d72 $9
da3 $b
dd9 $W
de8 $B
e19 $#
e25 $N
e31 $^
e33 $G
e4a $n
e4d $E
e6e $\
e77 $V
eb6 $q
edc $_
f08 $;
f46 $g
f52 $m
f78 $<
fa1 $}
fc0 $)

The two collisions are resolved by the remaining 4 bits displayed by 
that patch.

Davis

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