Base64 an encoding scheme to represent binary data using only printable (text) characters.
Encoding is not encryption. With Encryption you need a key to Encrypt and the Decrypt.
Many web applications use Base64 to transmit binary data within cookies, other parameters and hide sensitive data to prevent it being read of modified.
Base64 is not a secure way of storing critical data as it is reversible and this Post will show you show you how to Encode data and then decode.
128 + 16 + 8 = 152
128 + 64 + 16 + 1 = 209
128 + 32 + 4 = 164
Once converted to 6Bits get the value of each binary string.
38 = m
13 = N
6 = G
36 = k
Take the Base64 Encoded value.
Result is the correct values we started with. So these have been Encoded and the Decodes.