XWIS:APGAR: Difference between revisions
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APGAR is a token sent by a C&C game to tell XWIS the players' password. The password is encrypted using a weak algorithm. | APGAR is a token sent by a C&C game to tell XWIS the players' password. The password is encrypted using a weak algorithm. This is a one-way encryption, i.e. you cannot find the original password from it's encrypted form. | ||
Pseudo-code to calculate the password from an 8 letter input: | |||
<pre> | <pre> | ||
function apgar(input) | |||
lookup = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789" | lookup = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789" | ||
out = "" | out = "" | ||
| Line 22: | Line 21: | ||
return out | return out | ||
</pre> | </pre> | ||
A C++ implementation of this algorithm: | A C++ implementation of this algorithm: | ||
| Line 41: | Line 39: | ||
return out; | return out; | ||
} | } | ||
</pre> | </pre> | ||
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apgar Ykbcaxop 0 | apgar Ykbcaxop 0 | ||
</pre> | </pre> | ||
The closing zero seems to have no special function. | The closing zero seems to have no special function. | ||
[[Category:XWIS Protocol]] | [[Category:XWIS Protocol]] | ||
Revision as of 00:06, 19 June 2008
APGAR is a token sent by a C&C game to tell XWIS the players' password. The password is encrypted using a weak algorithm. This is a one-way encryption, i.e. you cannot find the original password from it's encrypted form.
Pseudo-code to calculate the password from an 8 letter input:
function apgar(input)
lookup = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789"
out = ""
i = 1
while (i <= 8)
left = ascii value of input[ i ]
right = ascii value of input[ length[input] - i ]
if left is odd
x = ((left * 2) XOR (left AND 1)) AND right
else
x = left XOR right
out += lookup[x AND 63]
i++
return out
A C++ implementation of this algorithm:
std::string apgar(std::string input) {
std::string lookup = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789";
std::string out = "";
int i = 0;
while (i < 8) {
unsigned char left = input[i];
unsigned char right = input[input.length() - i];
unsigned char x = left & 1 ? ((left << 1) ^ (left & 1)) & right : left ^ right;
out += lookup[x & 63];
i++;
}
return out;
}
Example (decrypted password "reneproj"):
apgar Ykbcaxop 0
The closing zero seems to have no special function.