A Fine Day

rgbCTF 2020
Cryptography
hmmm
July 15th, 2020
Classical Easy


It's a fine day to break some ciphers!

Ciphertext:

Sujd jd bgxopksbm ljsu tg tqqjgb xjkubo. Tqqjgb xjkubod tob t qvor vq dhidsjshsjvg xjkubo. Jsd nbp xvgdjdsd vq slv ghribod, t tgm i. Sv bgxopks t cbssbo, rhcsjkcp jsd kctxb jg sub tckutibs (dv t=0, i=1, bsx.) ip t, tgm subg tmm i. Qjgtccp stnb suts rvm 26 tgm xvgwbos js itxn jgsv t xutotxsbo.
Sub tqqjgb xjkubo jdg's obtccp suts dsovgf. Djgxb js'd rvm 26, subob tob vgcp t qbl uhgmobm mjqqbobgs nbpd, lujxu xtg ib btdjcp iohsb qvoxbm. Tgpltp, ubob'd pvho qctf: ofiXSQ{t_qjgb_tqqjgb_xjkubo}

Plug ciphertext into quipqiup.

Flag: rgbCTF{a_fine_affine_cipher}