Sentence that uses every base64 character

Question

I am trying to construct a sentence/letter combination that will return every base64 character, but failing to find a word for purposes of unit testing.

The unit tests I have so far are failing to hit the lines that handle the + and / characters. While I can sling a them at the encoder/decoder directly it would be nice to have a human readable source (the base64 equivalent of 'the quick brown dog').

Answer 1

Here is a Base64 encoded test string that includes all 64 possible Base64 symbols:

char base64_encoded_test[] =
"U28/PHA+VGhpcyA0LCA1LCA2LCA3LCA4LCA5LCB6LCB7LCB8LCB9IHRlc3RzIEJhc2U2NCBlbmNv"
"ZGVyLiBTaG93IG1lOiBALCBBLCBCLCBDLCBELCBFLCBGLCBHLCBILCBJLCBKLCBLLCBMLCBNLCBO"
"LCBPLCBQLCBRLCBSLCBTLCBULCBVLCBWLCBXLCBYLCBZLCBaLCBbLCBcLCBdLCBeLCBfLCBgLCBh"
"LCBiLCBjLCBkLCBlLCBmLCBnLCBoLCBpLCBqLCBrLCBsLCBtLCBuLCBvLCBwLCBxLCByLCBzLg==";

char base64url_encoded_test[] =
"U28_PHA-VGhpcyA0LCA1LCA2LCA3LCA4LCA5LCB6LCB7LCB8LCB9IHRlc3RzIEJhc2U2NCBlbmNv"
"ZGVyLiBTaG93IG1lOiBALCBBLCBCLCBDLCBELCBFLCBGLCBHLCBILCBJLCBKLCBLLCBMLCBNLCBO"
"LCBPLCBQLCBRLCBSLCBTLCBULCBVLCBWLCBXLCBYLCBZLCBaLCBbLCBcLCBdLCBeLCBfLCBgLCBh"
"LCBiLCBjLCBkLCBlLCBmLCBnLCBoLCBpLCBqLCBrLCBsLCBtLCBuLCBvLCBwLCBxLCByLCBzLg==";

It decodes to a string composed entirely of relatively human-readable text:

char test_string[] = "So?<p>"
    "This 4, 5, 6, 7, 8, 9, z, {, |, } tests Base64 encoder. "
    "Show me: @, A, B, C, D, E, F, G, H, I, J, K, L, M, "
    "N, O, P, Q, R, S, T, U, V, W, X, Y, Z, [, \\, ], ^, _, `, "
    "a, b, c, d, e, f, g, h, i, j, k, l, m, n, o, p, q, r, s.";

This decoded string contains only letters in the limited range of isprint()'able 7-bit ASCII characters (space through '~').

Since I did it, I would argue that it is possible :-).

Answer 2

You probably can't do that.

/ in base64 encodes 111111 (6 '1' bits).

As all ASCII (which are the type-able and printable characters) are in the range of 0-127 (i.e. 00000000 and 01111111), the only ASCII character that could be encoded using '/' is the ASCII character with the code 127, which is the non-printable DEL character.

If you allow values higher than 127, you could have a printable but non-typeable string.