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* http://www.apache.org/licenses/LICENSE-2.0
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* Unless required by applicable law or agreed to in writing,
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package org.apache.cayenne.configuration;
/**
* The ROT-47 password encoder passes the text of the database password through a simple
* Caesar cipher to obscure the password text. The ROT-47 cipher is similar to the ROT-13
* cipher, but processes numbers and symbols as well. See the Wikipedia entry on <a
* href="http://en.wikipedia.org/wiki/Rot-13">ROT13</a> for more information on this
* topic.
*
* @since 3.0
*/
public class Rot47PasswordEncoder implements PasswordEncoding {
public String decodePassword(String encodedPassword, String key) {
return rotate(encodedPassword);
}
public String encodePassword(String normalPassword, String key) {
return rotate(normalPassword);
}
/**
* Applies a ROT-47 Caesar cipher to the supplied value. Each letter in the supplied
* value is substituted with a new value rotated by 47 places. See <a
* href="http://en.wikipedia.org/wiki/ROT13">ROT13</a> for more information (there is
* a subsection for ROT-47).
* <p>
* A Unix command to perform a ROT-47 cipher is:
*
* <pre>
* tr '!-~' 'P-~!-O'
* </pre>
*
* @param value The text to be rotated.
* @return The rotated text.
*/
public String rotate(String value) {
if (value == null) {
return null;
}
int length = value.length();
StringBuilder result = new StringBuilder();
for (int i = 0; i < length; i++) {
char c = value.charAt(i);
// Process letters, numbers, and symbols -- ignore spaces.
if (c != ' ') {
// Add 47 (it is ROT-47, after all).
c += 47;
// If character is now above printable range, make it printable.
// Range of printable characters is ! (33) to ~ (126). A value
// of 127 (just above ~) would therefore get rotated down to a
// 33 (the !). The value 94 comes from 127 - 33 = 94, which is
// therefore the value that needs to be subtracted from the
// non-printable character to put it into the correct printable
// range.
if (c > '~')
c -= 94;
}
result.append(c);
}
return result.toString();
}
}