Excellent Crackme
We know one can do pretty much everything in Excel spreadsheets, but this...

```

1-Download VolgaCTF_excel_crackme.xlsm
2-Remove protections with Advanced Office Password Recovery
3-In this file, two data matrices are observed.
3-1-Data Matrice=> Cell(100,100):Cell(144,144) =>Matrice1[45*45]
3-2-Calculated Matrice=> Cell(100,145):Cell(144,145) =>Matrice2[45*1]

4-Matrice1[45*45] * FlagMatrice[45*1]= Matrice2[45*1]

5-FlagMatrice[45*1]=Matrice2 * Invert(Matrice1)

6-use OnlineMathTools.com to To Invert and multiply

7-Change bytes to text and get flag: VolgaCTF{7h3_M057_M47h_cr4ckM3_y0u_3V3R_533N}

```