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  1. POPython TEA implementation
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    <p>Anybody knows proper python implementation of TEA (Tiny Encryption Algorithm)? I tried the one I've found here: <a href="http://sysadminco.com/code/python-tea/" rel="nofollow noreferrer">http://sysadminco.com/code/python-tea/</a> - but it does not seem to work properly.</p> <p>It returns different results than other implementations in C or Java. I guess it's caused by completely different data types in python (or no data types in fact).</p> <p>Here's the code and an example:</p> <pre><code>def encipher(v, k): y=v[0];z=v[1];sum=0;delta=0x9E3779B9;n=32 w=[0,0] while(n&gt;0): y += (z &lt;&lt; 4 ^ z &gt;&gt; 5) + z ^ sum + k[sum &amp; 3] y &amp;= 4294967295L # maxsize of 32-bit integer sum += delta z += (y &lt;&lt; 4 ^ y &gt;&gt; 5) + y ^ sum + k[sum&gt;&gt;11 &amp; 3] z &amp;= 4294967295L n -= 1 w[0]=y; w[1]=z return w def decipher(v, k): y=v[0] z=v[1] sum=0xC6EF3720 delta=0x9E3779B9 n=32 w=[0,0] # sum = delta&lt;&lt;5, in general sum = delta * n while(n&gt;0): z -= (y &lt;&lt; 4 ^ y &gt;&gt; 5) + y ^ sum + k[sum&gt;&gt;11 &amp; 3] z &amp;= 4294967295L sum -= delta y -= (z &lt;&lt; 4 ^ z &gt;&gt; 5) + z ^ sum + k[sum&amp;3] y &amp;= 4294967295L n -= 1 w[0]=y; w[1]=z return w </code></pre> <p>Python example:</p> <pre><code>&gt;&gt;&gt; import tea &gt;&gt;&gt; key = [0xbe168aa1, 0x16c498a3, 0x5e87b018, 0x56de7805] &gt;&gt;&gt; v = [0xe15034c8, 0x260fd6d5] &gt;&gt;&gt; res = tea.encipher(v, key) &gt;&gt;&gt; "%X %X" % (res[0], res[1]) **'70D16811 F935148F'** </code></pre> <p>C example:</p> <pre><code>#include &lt;unistd.h&gt; #include &lt;stdio.h&gt; void encipher(unsigned long *const v,unsigned long *const w, const unsigned long *const k) { register unsigned long y=v[0],z=v[1],sum=0,delta=0x9E3779B9, a=k[0],b=k[1],c=k[2],d=k[3],n=32; while(n--&gt;0) { sum += delta; y += (z &lt;&lt; 4)+a ^ z+sum ^ (z &gt;&gt; 5)+b; z += (y &lt;&lt; 4)+c ^ y+sum ^ (y &gt;&gt; 5)+d; } w[0]=y; w[1]=z; } int main() { unsigned long v[] = {0xe15034c8, 0x260fd6d5}; unsigned long key[] = {0xbe168aa1, 0x16c498a3, 0x5e87b018, 0x56de7805}; unsigned long res[2]; encipher(v, res, key); printf("%X %X\n", res[0], res[1]); return 0; } $ ./tea **D6942D68 6F87870D** </code></pre> <p>Please note, that both examples were run with the same input data (v and key), but results were different. I'm pretty sure C implementation is correct - it comes from a site referenced by wikipedia (I couldn't post a link to it because I don't have enough reputation points yet - some antispam thing)</p>
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