Algorithm Base64

Suppose we want to encode <toto, so : 

< t o t o

60 116 111 116 111  // in decimal

00111100 01110100 01101111 01110100 01101111 // in binary

00111100 01110100 01101111 01110100 01101111 00000000 // add optionnal complement (00000000) to have a multiple of 24 bits

001111 000111 010001 101111 011101 000110 111100 000000 // group of 6 * 3 bits

P      H      R      v      d      G      8       =     // use of Base64 index (see below)


If we want to encode <toto>

< t o t o >

60 116 111 116 111 62 // in decimal

00111100 01110100 01101111 01110100 01101111 00111110 // in binary

001111 000111 010001 101111 011101 000110 111100 111110 // in groupe of 3 x 6 bits. There is no rest, so no complement to add

P      H      R      v      d      G      8      + 

Remark : the before last character is still a 8 because the character > is 00111110 in binary. So the first 2 bits are zeros and so it is still a 8 value.

--------

Base64 index : 


        Valeur Codage         Valeur Codage         Valeur Codage         Valeur Codage
      0 000000 A           17 010001 R           34 100010 i           51 110011 z
      1 000001 B           18 010010 S           35 100011 j           52 110100 0
      2 000010 C           19 010011 T           36 100100 k           53 110101 1
      3 000011 D           20 010100 U           37 100101 l           54 110110 2
      4 000100 E           21 010101 V           38 100110 m           55 110111 3
      5 000101 F           22 010110 W           39 100111 n           56 111000 4
      6 000110 G           23 010111 X           40 101000 o           57 111001 5
      7 000111 H           24 011000 Y           41 101001 p           58 111010 6
      8 001000 I           25 011001 Z           42 101010 q           59 111011 7
      9 001001 J           26 011010 a           43 101011 r           60 111100 8
     10 001010 K           27 011011 b           44 101100 s           61 111101 9
     11 001011 L           28 011100 c           45 101101 t           62 111110 +
     12 001100 M           29 011101 d           46 101110 u           63 111111 /
     13 001101 N           30 011110 e           47 101111 v
     14 001110 O           31 011111 f           48 110000 w        (complément) =
     15 001111 P           32 100000 g           49 110001 x
     16 010000 Q           33 100001 h           50 110010 y