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Revision as of 00:24, 1 June 2013 by Yellows8 (talk | contribs)
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Index Word Description
0 Header code [0x00470104]
1 Output buffer size
2 Input buffer size
3 Block size
4 Nonce size, size 12 is used if this is >12.
5 (inputbufsize<<4) | 10
6 Input encrypted data buffer ptr
7 (outputbufsize<<4) | 12
8 Output cleartext data buffer ptr


Index Word Description
0 Header code
1 Result code


This decrypts the input data with AES-CCM using keytype2, when the input noncesize is <12 the low 2-bits are cleared in the noncesize. The 12-byte nonce buffer used by NS is cleared to all-zero, then the nonce from inputbuf+0 with the noncesize is copied to this nonce buffer. NS then uses PS:EncryptSignDecryptVerifyAesCcm with keytype2 and with the above nonce buffer, where the inputptr is inputbuf+noncesize, outputptr is outputbuf+0, and size is inputbuffersize - noncesize - 16.

After decryption, NS copies the data at outbuf+blocksize to outbuf+blocksize+noncesize, with size inputbuffersize-blocksize-16. NS then copies the nonce from inputbuf+0 with the noncesize, to outbuf+blocksize.