docs: updated documentation on ballot encoding

docs/ballot_encoding.md

@@ -13,7 +13,7 @@ The answers to questions are encoded in the following way, with one question per
 
 TYPE = "select"|"text"|"rank"
 SEP = ":"
-ID = 3 bytes, encoded in base64
+ID = 8 bytes UUID encoded in base64 = 12 bytes
 ANSWERS = <answer>[","<answer>]*
 ANSWER = <select_answer>|<text_answer>|<rank_answer>
 SELECT_ANSWER = "0"|"1"
@@ -39,11 +39,11 @@ For the following questions :
 A possible encoding of an answer would be (by string concatenation):
 
 ```
-"select:3fb2:0,0,0,1,0\n" +
+"select:base64(D0Da4H6o):0,0,0,1,0\n" +
 
-"rank:19c7:0,1,2\n" +
+"rank:base64(19c7cd13):0,1,2\n" +
 
-"text:cd13:base64("Noémien"),base64("Pierluca")\n"
+"text:base64(wSfBs25a):base64("Noémien"),base64("Pierluca")\n"
 ```
 
 ## Size of the ballot
@@ -53,15 +53,15 @@ voting process, it is important that all encrypted ballots have the same size. T
 the form has an attribute called "BallotSize" which is the size
 that all ballots should have before they're encrypted. Smaller ballots should therefore be
 padded in order to reach this size. To denote the end of the ballot and the start of the padding,
-we use an empty line (\n\n). For a ballot size of 117, our ballot from the previous example
+we use an empty line (\n\n). For a ballot size of 144, our ballot from the previous example
 would then become:
 
 ```
-"select:3fb2:0,0,0,1,0\n" +
+"select:base64(D0Da4H6o):0,0,0,1,0\n" +
 
-"rank:19c7:0,1,2\n" +
+"rank:base64(19c7cd13):0,1,2\n" +
 
-"text:cd13:base64("Noémien"),base64("Pierluca")\n\n" +
+"text:base64(wSfBs25a):base64("Noémien"),base64("Pierluca")\n\n" +
 
 "ndtTx5uxmvnllH1T7NgLORuUWbN"
 ```
@@ -70,4 +70,4 @@ would then become:
 
 The encoded ballot must then be divided into chunks of 29 or less bytes since the maximum size supported by the kyber library for the encryption is of 29 bytes.
 
-For the previous example we would then have 5 chunks, the first 4 would contain 29 bytes, while the last chunk would contain a single byte.
+For the previous example we would then have 5 chunks, the first 4 would contain 29 bytes, while the last chunk would contain 28 bytes.