# Solution to A Bit of Light

#### by Evan Chen

• First, ignoring the bottom row gives 2×3 Braille cells. The first few letters say USE BRAILLE ASCII TO GET HEX. followed by more Braille, but as specified, using the ASCII Braille format to encode numbers. The rest of the Braille message is the hexadecimal string
696E743D3E6865783D3E535344
which says
int=>hex=>SSD.
• Following the electronic color code for resistor colors, each cell gives an eight-digit decimal number.
• These decimal numbers are converted to base 16, as indicated. The base 16 strings are actually 1337-ified, where A is replaced by 4, B replaced by 8, E replaced 3, and G replaced by 6. Reverting this, we find that the numbers are a subset of the string ABCDEFG.
• The clue "SSD" means seven-segment display: the letters indicate which LED's of a 7-segment display should be illuminated.
Thus each of the SSD LED's gives an unambiguous hexadecimal letter.
• The initial segment of the 7SD gives
DA7E 1919 07 22 CA5E 1310719A
(with the spaces!) followed by another hex string 432221707726202b7e7b1d076e.
• The initial segment is the date and United States patent number issued to Gilbert Vernam for the one-time pad, so this is just a roundabout way of saying to XOR the two hexadecimal strings (which both have equal length). Doing so gives another hex string 2A4C554D494E455343454E542A which then decrypts to the string
*LUMINESCENT*

Here is a complete breakdown of the puzzle.

# Cell Braille letter ASCII Resistor colors In base 16 7SD LED's 7SD XOR ASCII
#1 10
00
11
00
U n/a 00576822 8CD36 BCDEG
#2 01
10
10
00
S n/a 04768758 48C3F6 ABCEFG
#3 10
01
00
00
E n/a 00001164 48C ABC
#4 00
00
00
00
#5 10
10
00
00
B n/a 00000000
#6 10
11
10
00
R n/a 00000140 8C BC
#7 10
00
00
00
A n/a 04771318 48CDF6 ABCDFG
#8 01
10
00
00
I n/a 00000140 8C BC
#9 10
10
10
00
L n/a 04771318 48CDF6 ABCDFG
#10 10
10
10
00
L n/a 00000000
#11 10
01
00
00
E n/a 04771135 48CD3F ABCDEF
#12 00
00
00
00
n/a 00001164 48C ABC
#13 10
00
00
00
A n/a 00000000
#14 01
10
10
00
S n/a 00298294 48D36 ABDEG
#15 11
00
00
00
C n/a 00298294 48D36 ABDEG
#16 01
10
00
00
I n/a 00000000
#17 01
10
00
00
#18 00
00
00
00
n/a 04768758 48C3F6 ABCEFG
#19 01
11
10
00
T n/a 00314870 4CDF6 ACDFG
#20 10
01
10
00
#21 00
00
00
00
n/a 00000000
#22 11
11
00
00
G n/a 00000140 8C BC
#23 10
01
00
00
E n/a 00298198 48CD6 ABCDG
#24 01
11
10
00
T n/a 00000140 8C BC
#25 00
00
00
00
n/a 04771135 48CD3F ABCDEF
#26 10
11
00
00
H n/a 00001164 48C ABC
#27 10
01
00
00
E n/a 00000140 8C BC
#28 11
00
11
00
X n/a 04771318 48CDF6 ABCDFG
#29 00
01
01
00
. n/a 04768758 48C3F6 ABCEFG
#30 00
00
00
00
n/a 00000000
#31 00
11
10
00
6 i 00036086 8CF6 BCFG 2 *
#32 00
01
10
00
9 00298198 48CD6 ABCDG A
#33 00
11
10
00
6 n 00298294 48D36 ABDEG 4 L
#34 10
01
00
00
E 00298294 48D36 ABDEG C
#35 00
11
11
00
7 t 00298294 48D36 ABDEG 5 U
#36 00
11
01
00
4 00000140 8C BC 5
#37 00
11
00
00
3 = 00001164 48C ABC 4 M
#38 11
01
00
00
D 04771135 48CD3F ABCDEF D
#39 00
11
00
00
3 > 00001164 48C ABC 4 I
#40 10
01
00
00
E 00001164 48C ABC 9
#41 00
11
10
00
6 h 00298294 48D36 ABDEG 4 N
#42 00
10
11
00
8 05034998 4CD3F6 ACDEFG E
#43 00
11
10
00
6 e 00298294 48D36 ABDEG 4 E
#44 00
10
01
00
5 04771135 48CD3F ABCDEF 5
#45 00
11
11
00
7 x 00298294 48D36 ABDEG 5 S
#46 00
10
11
00
8 00840694 CD3F6 CDEFG 3
#47 00
11
00
00
3 = 00001164 48C ABC 4 C
#48 11
01
00
00
#49 00
11
00
00
3 > 00001164 48C ABC 4 E
#50 10
01
00
00
E 00840694 CD3F6 CDEFG 5
#51 00
10
01
00
5 S 00000140 8C BC 4 N
#52 00
11
00
00
3 00576822 8CD36 BCDEG E
#53 00
10
01
00
5 S 04771135 48CD3F ABCDEF 5 T
#54 00
11
00
00
3 00001164 48C ABC 4
#55 00
11
01
00
4 D 05034998 4CD3F6 ACDEFG 2 *
#56 00
11
01
00