Unable to get AES 128 encryption/decryption working

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1

I have already looked at the thread viewtopic.php?f=34&t=40497 and tried to follow up on that thread – it does not seem to help.

I am unable to figure out how to use AES 128 encryption. Roku box keeps rebooting in most of the attempts. Otherwise, setup call returns -1. It is working fine if I use "bf” and a 64 bit initialization vector.

Appreciate your help.

Here is my code snippet - wondering if I am doing something wrong

alg = "aes-128-cbc"
    pad = 1 
    encryptKey = "10a58869d74be5a374cf867cfb473859"
    IV = "00000000000000000000000000000000"
    plainText = "00000000000000000000000000000000"

    encResult = crypto_encrypt(alg, encryptKey, IV, plainText, pad)
    

Function crypto_encrypt(alg as String, encryptKey As String, IV As String, text As String, pad as Integer) As String

   crypto = CreateObject("roEVPCipher")
   res = crypto.Setup(true, alg,encryptKey,IV,pad)
   print res
   
   ba = CreateObject("roByteArray")
   ba.FromAsciiString(text)

   enc = crypto.Process(ba)
   
   return enc.ToHexString()
   
End function
2

alg =“aes-128-cbc”
pad = 1
encryptKey =“d4fcf78158762c2b”
IV =“d8fcf78848762c4b”
plainText = token
encResult = crypto_encrypt(alg,encryptKey,IV,plainText,pad)

function crypto_encrypt(alg, encryptKey, IV, plainText, pad)
encrypt = false
crypto = CreateObject(“roEVPCipher”)
res = crypto.Setup(encrypt,alg,encryptKey,IV,pad)

ba = CreateObject(“roByteArray”)
ba.FromAsciiString(plainText)
enc = crypto.Process(ba)
return (enc.ToBase64String())

end function

this is my code for aes-128-cbc decryption. but i’m not able to setUp cipher. setup always call -1.Please suggest me, how to use aes-128-cbc cipher decryption

3

Your key and IV should be 16 hex characters. Yours are only 8.

4

plaintext = “DWFf4sXI0idwUcQ8lMdung==”
cipher= “aes-128-cbc”
decryptKey= “2b7e151628aed2a6abf7158809cf4f3c”
IV =“000102030405060708090a0b0c0d0e0f”
pad = 1
decResult = crypto_decrypt(cipher, decryptKey, IV, plaintext, pad)

Function crypto_decrypt(cipher as String, decryptKeyAs String, IV As String, plaintext As String, pad as Integer) As String
crypto = CreateObject(“roEVPCipher”)
res = crypto.Setup(false, cipher,decryptKey,IV,pad)
print res
ba = CreateObject(“roByteArray”)
ba.FromBase64String(plaintext)
enc = crypto.Process(ba)
?"enc"enc
return enc.ToAsciiString()’
End function

when i trying to process its showing invalid. . any thoughts?

5

looks like AES 128 only accepts encryption/decryption key 16 bytes long , your is bigger

encryptKey = "10a58869d74be5a374cf867cfb473859"

a key like this should be working

10a58869d74be5a3

16 bytes key for AES-128 encryption (16 * 8 = 128)

https://crypto.stackexchange.com/questions/44271/what-is-the-maximum-key-size-for-a-128-bit-aes