AutoHotkey Community

Password = AutoHotkey
Data = 12345678901234567
Len := StrLen(Data)
Buffer = %Data%0123456789abcdef ; allocate 16 byte more space

size := Crypt_AES(&Buffer, Len, Password, 256, 1)
MsgBox % "Plaintext size = " Len "`nCiphertext size = " size "`nCiphertext: " SubStr(Buffer,1,size)

size := Crypt_AES(&Buffer, size, Password, 256, 0)
MsgBox % "`Plaintext size = " size "`nPlaintext: " SubStr(Buffer,1,size)

Crypt_AES(pData, nSize, sPassword, SID = 256, bEncrypt = True) {
   CALG_AES_256 := 1 + CALG_AES_192 := 1 + CALG_AES_128 := 0x660E
   CALG_SHA1 := 1 + CALG_MD5 := 0x8003
   DllCall("advapi32\CryptAcquireContextA", "UintP", hProv, "Uint", 0, "str"
   , "Microsoft Enhanced RSA and AES Cryptographic Provider" . (A_OSVersion="WIN_XP" ? " (Prototype)" : ""), "Uint", 24, "Uint", 0)
   DllCall("advapi32\CryptCreateHash", "Uint", hProv, "Uint", CALG_SHA1, "Uint", 0, "Uint", 0, "UintP", hHash)
   DllCall("advapi32\CryptHashData", "Uint", hHash, "Uint", &sPassword, "Uint", StrLen(sPassword), "Uint", 0)
   DllCall("advapi32\CryptDeriveKey", "Uint", hProv, "Uint", CALG_AES_%SID%, "Uint", hHash, "Uint", SID<<16, "UintP", hKey)
   DllCall("advapi32\CryptDestroyHash", "Uint", hHash)
   If bEncrypt
      DllCall("advapi32\CryptEncrypt", "Uint", hKey, "Uint", 0, "Uint", True, "Uint", 0, "Uint", pData, "UintP", nSize, "Uint", nSize+16)
   Else  DllCall("advapi32\CryptDecrypt", "Uint", hKey, "Uint", 0, "Uint", True, "Uint", 0, "Uint", pData, "UintP", nSize)
   DllCall("advapi32\CryptDestroyKey", "Uint", hKey)
   DllCall("advapi32\CryptReleaseContext", "Uint", hProv, "Uint", 0)
   Return   nSize
}

Password = AutoHotkey
Data = 2aosi231 ; encrypted data before with the same password
Len := StrLen(Data)
Buffer = %Data%0123456789abcdef ; allocate 16 byte more space

size := Crypt_AES(&Buffer, size, Password, 256, 0)
MsgBox % "`Plaintext size = " size "`nPlaintext: " SubStr(Buffer,1,size)

Crypt_AES(&Buffer, size, Password, 256, 0)