zipkeygen tests the key derivation of golang's crypto packages and compares the
 results to those of Dr. Brian Gladman's WinZip AES crypto functions.
 His website is at: http://www.gladman.me.uk/cryptography_technology/fileencrypt/

 WinZip AES specifies
  1. Encrpytion-Decryption w/ AES-CTR (128, 192, or 256 bits)
  2. Key generation with PBKDF2-HMAC-SHA1 (1000 iteration count) that
generates a key broken into the following:
        a. First m bytes is for the encryption key
        b. Next n bytes is for the authentication key
        c. Last 2 bytes is the password verification value.
  3. Following salt lengths are used w/ password during keygen:
        AES Key Size    | Salt Size
        ------------------------------
        128bit(16bytes) | 8 bytes
        192bit(24bytes) | 12 bytes
        256bit(32bytes) | 16 bytes
  4. Authentication Key is same size as AES key.
  5. Authentication with HMAC-SHA1-80 (truncated to 80bits).
  6. KeyLen input into PBKDF2: AES Key Size + Auth Key Size + 2 bytes (pw verify)
        a. AES 128 = 16 + 16 + 2 = 34 bytes of key material
        b. AES 192 = 24 + 24 + 2 = 50 bytes of key material
        c. AES 256 = 32 + 32 + 2 = 66 bytes of key material
  7. A new set of encryption/auth keys + salt are generated for each file encrypted
  in the .zip file

Results:

Test 1
Expected first 16 bytes: 5c75cef01a960df74cb6b49b9e38e6b5
Actual first 16 bytes: 5c75cef01a960df74cb6b49b9e38e6b5
Match: true

Test 2
Expected first 16 bytes: d1daa78615f287e6a1c8b120d7062a49
Actual first 16 bytes: d1daa78615f287e6a1c8b120d7062a49
Match: true

PW->Key: 142f8fafce633ccd9265d90fc8fe425257dcb1a5d1f5cc961ffef716b20ea60d1296
Encryption key: 142f8fafce633ccd9265d90fc8fe4252
Authentication key: 57dcb1a5d1f5cc961ffef716b20ea60d
PW Verify Code: 1296

Encryption key: 142f8fafce633ccd9265d90fc8fe425257dcb1a5d1f5cc961ffef716b20ea60d
Authentication key: 1296ebadec5f39ba8a19b30a5cb1136c190bf2bfddef54f75440a3df78c56f8f
PW Verify Code: 23be
len(enc)+len(auth)+len(pwv)=66

Testing decryption of zip.
Raw Encrypted Zip Data
Salt: 0989b46306bd8f8293a389613db826d1
PWV: a3e6
Data: e0ba876cd116a6df91cf7f8a14
AuthCode: b89f23e399cb17d5651a

Encryption key: 8d11d79d63e5d18904ae6acb77cfed5579912f8bc321063ba9d607f709af372a
Auth Key: 6fa064bf1816d83a802855a4e812286f9f47c60698fe61fe4ba12a0b759520ee
PWV Code: a3e6

Password verification passed.
Authentication passed.
IV: 01 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
IVint: 1
Decryption succeeded.
Plaintext: "Hello World\r\n"