Base 64 Encoding

If you are working in the DFIR, you might have encountered Base64 Code many times. In this blog post, we will talk about the basics of base64 encoding.

ASCII Data - Each Character turns into one byte
A = 65 (Binary 0b01000001)
B = 66 (Binary 0b01000010)
C = 67 (Binary 0b01000011)

The 3 Letter String = 24 Bit
ABC = 0b010000010100001001000011
For base64 - we'll need ot break it in the group of 6 bits. 6 Bits will have 64 Combination and will need 64 Characters to encode it.

Characters used are as follows:
ABC...Z = 0-25
abc...z =26-51
0123..9 = 52-61
+,/ = 62,63

I am going to use spaces for the ease of reading
ABC  = 0b01000001 01000010 01000011
6-bit Groups = 0b010000 010100 001001 000011
Decimal = 16 20 9 3
base64 = Q U J D