Hi, The IEEE 802.11i-2004 says: 
 
The PTK is generated by concatenating the following attributes: PMK, A
+P nonce (ANonce), STA nonce (SNonce), AP MAC address, and STA MAC add
+ress.
You should better check this as the order is important.

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This isn't exactly what you are doing here : 
my $a = "Pairwise key expansion"; # application-specific data
my $b = $amac.$smac.$snonce.$anonce;
my $r = "";
    for(my $i=0;$i<4;$i++){
        my $data = $a."\x00".$b.$i;

[download]
The product is then put through PBKDF2-SHA1 as the cryptographic hash function. The PBKDF2 key derivation function has five input parameters: 
DK = PBKDF2(PRF, Password, Salt, c, dkLen)

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where:
  • PRF is a pseudorandom function of two parameters with output length hLen (e.g. a keyed HMAC)
  • Password is the master password from which a derived key is generated
  • Salt is a cryptographic salt
  • c is the number of iterations desired
  • dkLen is the desired length of the derived key
  • DK is the generated derived key

    • For more on pbkdf2 used in perl check this link PBKDF2 crypt
    Here's some code used to do this pbkdf2.pl

    In reply to Re: HMAC_SHA1 Implementation for WPA by cord-bin
    in thread [SOLVED] HMAC_SHA1 Implementation for WPA by return0

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