What do I use…?

What do I use…? Can you solve the rebus and decipher the code?

• Each group of four numbers represents a letter.
• YzNSaGJucGg=, then ZG1WeWMyVT0=, then ZDI5eVpBPT0=, then YkdWMGRHVnk=.
• This was a fun puzzle. I am not a big rebus fan but I appreciate how it was used in conjunction with other steps. I also like how the puzzle has an obvious theme, but I think it would be better if rot13(gur nafjre svg vagb gur gurzr, naq jnf eryngrq gb zhfvp). – floraline May 8 '18 at 19:05
• I also think the puzzle suffered from rot13(ab nccnerag ernfba gb hfr onfr64 be ebg13 gb qrpvcure gur uvagf naq nafjre. V whfg unq gb thrff juvpu pvcure gb hfr). – floraline May 8 '18 at 19:07

I think you use:

The web browser Chrome

Finding the hints:

The hint is encoded in base64, decoding this twice gives us the plaintext: stanza, then verse, then word, then letter. This pattern can probably be used to resolve the four-letter codes into letters to form the final word, and it also tells us that these letters will be found in the text of some poem or song. This is further suggested by the music notes scattered in the image, and the final 6-letter word is probably related to music.

Solving the rebus:

I believe the rebus will point us to the song that we need to find the letters. One possible solution for the rebus is (New) + Sea + Land, or New Zealand. With the previous clues in mind, I can think of only the national anthem.

Using the numbers: 1534 2625 3333 2341 5841 4512

Use the English text of the New Zealand national anthem to find the answer.
1534, or stanza 1, line 5, word 3 (triple), letter 4: p
2625, or stanza 2, line 6, word 2 (corruption), letter 5: u
3333, or stanza 3, line 3, word 3 (then), letter 3: e
2341, or stanza 2, line 3, word 4 (bless), letter 1: b
5841, or stanza 5, line 8, word 4 (Zealand), letter 1: z
4512, or stanza 4, line 5, word 1 (From), letter 2: r
This gives us the final word puebzr. Decipher using rot13 to find out what our friend uses:
Chrome

• Looks good! You got half of solution right. And sorry, I’ve just found a tiny mistake in the code, I will fix it immediately. – Lypyrhythm May 8 '18 at 17:41