Hi
I’m looking to rework some code I found online so I can use it on Vera, and while I’ve managed to translate / convert a number of things, I’ve got stuck on a few things it does, around encryption/decryption etc.
All the original Lua code is here - > (https://forum.logicmachine.net/showthread.php?tid=232&pid=16580#pid16580 )
Plus there looks to be a python version too here - > (https://github.com/florianholzapfel/panasonic-viera/issues/9#issuecomment-476919658)
Here’s an extract of the code where AES 128 CBC is required?
function encrypt_soap_payload(data, key, hmac_key, iv)
payload = '000000000000'
n = #data
payload = payload .. string.char(bit.band(bit.rshift(n, 24), 0xFF))
payload = payload .. string.char(bit.band(bit.rshift(n, 16), 0xFF))
payload = payload .. string.char(bit.band(bit.rshift(n, 8), 0xFF))
payload = payload .. string.char(bit.band(n, 0xFF))
payload = payload .. data
aes_cbc, err = aes:new(key, nil, aes.cipher(128, 'cbc'), { iv = iv }, nil, 1)
ciphertext = aes_cbc:encrypt(payload)
sig = encdec.hmacsha256(ciphertext, hmac_key, true)
encrypted_payload = encdec.base64enc(ciphertext .. sig)
return encrypted_payload
end
function decrypt_soap_payload(data, key, hmac_key, iv)
aes_cbc, err = aes:new(key, nil, aes.cipher(128, 'cbc'), { iv = iv }, nil, 0)
decrypted = aes_cbc:decrypt(encdec.base64dec(data))
decrypted = string.gsub(string.sub(lmcore.strtohex(decrypted), 33), '%x%x', function(value) return string.char(tonumber(value, 16)) end)
return decrypted
end
I can get to the point where I can create the parameters for the payload encrypt request (example below), it’s just the encryption/decryption I cant do..
data="1234"
key="\\S„ßÍ}/Ìa5!"
hmac_key="¹jz¹2¸F\r}òcžÎ„ 臧.ª˜¹=¤µæŸ"
iv=" {¬£áæ‚2žâ3ÐÞË€ú "
I’ve found this aes.lua (https://github.com/openresty/lua-resty-string/blob/master/lib/resty/aes.lua ) module online, but that requires loads of others modules too, most notably ffi.lua. Which I’d ideally like to avoid.
I also came across this aes128.lua (https://github.com/somesocks/lua-lockbox/blob/master/lockbox/cipher/aes128.lua ) but i’m not sure how that handles all the other parameters e.g specify the cbc aspect etc.
Finally there’s this aes256ecb.lua script (https://github.com/idiomic/Lua_AES/blob/master/AES.lua) , could that be converted to aes 128 cbc and then used in the above?
Any help/advice on this would be appreciated..