Day 04: Bracelet

Description

Santa was given a nice bracelet by one of his elves. Little does he know that the secret admirer has hidden a message in the pattern of the bracelet…

Hints:

• No internet is required - only the bracelet
• The message is encoded in binary
• Violet color is the delimiter
• Colors have a fixed order
• Missing colors matter

Solution

Lets start by transcribing the beads of the bracelet, and we know that purple is a delimiter

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g|py|gb|pg|gb|pgby|gby|gb|by|by|gby|py|by||gby|gy|gy|by|by|g|gb|pgb|by|gby|by|g|


g=green
p=pink
y=yellow
b=blue

Given the clues that the order is always the same, we suspect that each color represents a place in the binary number, and presence of the bead means a 1 in that position, and absence of the color bead a 0

we have one grouping with all colors, so we know the order is pgby, and if all beads are present, it corresponds to 1111, and if none are present it is 0000 etc

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pgby
----
0000
0001 y
0010 b
0011 by
0100 g
0101 gy
..etc

then to convert this to ascii characters, two groups form one letter

Transcribing the whole bracelet gives the following binary code:

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01001001 01101100 01101111 01110110 00110011 01111001 00110000 01110101 01010011 00110100 01101110 00110111 00110100

which when converted to ascii spells Ilov3y0uS4n74

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