charT CPasswordCharPool::GetRandomChar() const
{
ASSERT(m_char_array.length() > 0);
PWSrand *ri = PWSrand::GetInstance();
uint r = ri->RangeRand(static_cast<uint32>(m_char_array.length()));
return m_char_array.at(r);
}
StringX CPasswordCharPool::MakePronounceable() const
{
/**
* Following based on gpw.C from
* http://www.multicians.org/thvv/tvvtools.html
* Thanks to Tom Van Vleck, Morrie Gasser, and Dan Edwards.
*/
charT c1, c2, c3; /* array indices */
long sumfreq; /* total frequencies[c1][c2][*] */
long ranno; /* random number in [0,sumfreq] */
long sum; /* running total of frequencies */
uint nchar; /* number of chars in password so far */
PWSrand *pwsrnd = PWSrand::GetInstance();
stringT password(m_pwlen, 0);
/* Pick a random starting point. */
/* (This cheats a little; the statistics for three-letter
combinations beginning a word are different from the stats
for the general population. For example, this code happily
generates "mmitify" even though no word in my dictionary
begins with mmi. So what.) */
sumfreq = sigma; // sigma calculated by loadtris
ranno = static_cast<long>(pwsrnd->RangeRand(sumfreq+1)); // Weight by sum of frequencies
sum = 0;
for (c1 = 0; c1 < 26; c1++) {
for (c2 = 0; c2 < 26; c2++) {
for (c3 = 0; c3 < 26; c3++) {
sum += tris[int(c1)][int(c2)][int(c3)];
if (sum > ranno) { // Pick first value
password[0] = charT('a') + c1;
password[1] = charT('a') + c2;
password[2] = charT('a') + c3;
c1 = c2 = c3 = 26; // Break all loops.
} // if sum
} // for c3
} // for c2
} // for c1
/* Do a random walk. */
nchar = 3; // We have three chars so far.
while (nchar < m_pwlen) {
c1 = password[nchar-2] - charT('a'); // Take the last 2 chars
c2 = password[nchar-1] - charT('a'); // .. and find the next one.
sumfreq = 0;
for (c3 = 0; c3 < 26; c3++)
sumfreq += tris[int(c1)][int(c2)][int(c3)];
/* Note that sum < duos[c1][c2] because
duos counts all digraphs, not just those
in a trigraph. We want sum. */
if (sumfreq == 0) { // If there is no possible extension..
break; // Break while nchar loop & print what we have.
}
/* Choose a continuation. */
ranno = static_cast<long>(pwsrnd->RangeRand(sumfreq+1)); // Weight by sum of frequencies
sum = 0;
for (c3 = 0; c3 < 26; c3++) {
sum += tris[int(c1)][int(c2)][int(c3)];
if (sum > ranno) {
password[nchar++] = charT('a') + c3;
c3 = 26; // Break the for c3 loop.
}
} // for c3
} // while nchar
/*
* password now has an all-lowercase pronounceable password
* We now want to modify it per policy:
* If m_usedigits and/or m_usesymbols, replace some chars with
* corresponding 'leet' values
* Also enforce m_useuppercase & m_uselowercase policies
*/
if (m_usesymbols || m_usedigits) {
// fill a vector with indices of substitution candidates
vector<int> sc;
FillSC fill_sc(sc, (m_usedigits == TRUE), (m_usesymbols == TRUE));
for_each(password.begin(), password.end(), fill_sc);
if (!sc.empty()) {
// choose how many to replace (not too many, but at least one)
unsigned int rn = pwsrnd->RangeRand(sc.size() - 1)/2 + 1;
// replace some of them
RandomWrapper rnw;
random_shuffle(sc.begin(), sc.end(), rnw);
for (unsigned int i = 0; i < rn; i++)
leet_replace(password, sc[i], m_usedigits, m_usesymbols);
}
}
// case
uint i;
if (m_uselowercase && !m_useuppercase)
; // nothing to do here
else if (!m_uselowercase && m_useuppercase)
for (i = 0; i < m_pwlen; i++) {
if (_istalpha(password[i]))
password[i] = static_cast<charT>(_totupper(password[i]));
}
else if (m_uselowercase && m_useuppercase) // mixed case
for (i = 0; i < m_pwlen; i++) {
if (_istalpha(password[i]) && pwsrnd->RandUInt() % 2)
password[i] = static_cast<charT>(_totupper(password[i]));
}
return password.c_str();
}
charT CPasswordCharPool::GetRandomChar(CPasswordCharPool::CharType t) const
{
PWSrand *ri = PWSrand::GetInstance();
uint r = ri->RangeRand(static_cast<uint>(m_lengths[t]));
return GetRandomChar(t, r);
}