advapi32.dll CryptDecrypt to decrypt an openssl encrypted string

[James Abbott]

How is this done? I have attached a VB6 module modcrypt.bas by Barry Dunne which uses rc4 and Microsoft Base Cryptographic Provider 1.0...   I can get this to rc4 encrypt / decrypt under Windoze. Although it iterates the hashing of the password, then creates a session key from it, and the reverse is done for decryption (I imagine this must be changed to decrypt an openssl encrypted string). It also includes a password encrypt string?!   Likewise I can get openssl to encrypt / decrypt rc4 under Linux.   Now comes the tricky part. How can I modify modcrypt.bas to decrypt openssl encrypted strings? I believe Microsoft Base Cryptographic Provider 1.0 supports 40bit rc2 encryption. Am I better to use this, (ENCRYPT_ALGORITHM=CALG_RC2) with openssl (rc2-40cbc) as opensll uses 128 bit rc4 which I believe is unsupported by Microsoft Base Cryptographic Provider 1.0? Most importantly, when all I have is a password from openssl, how do I get the parameters to pass CryptDecrypt?   The function definition looks like this:   Private Declare Function CryptDecrypt Lib "advapi32.dll" _     (ByVal hKey As Long, _      ByVal hHash As Long, _      ByVal Final As Long, _      ByVal dwFlags As Long, _      ByVal pbData As String, _      ByRef pdwDataLen As Long) As Long   Thanks in advance, James.   Private Const SERVICE_PROVIDER As String = "Microsoft Base Cryptographic Provider v1.0" Private Const KEY_CONTAINER As String = "Metallica" Private Const PROV_RSA_FULL As Long = 1 Private Const PP_NAME As Long = 4 Private Const PP_CONTAINER As Long = 6 Private Const CRYPT_NEWKEYSET As Long = 8 Private Const ALG_CLASS_DATA_ENCRYPT As Long = 24576 Private Const ALG_CLASS_HASH As Long = 32768 Private Const ALG_TYPE_ANY As Long = 0 Private Const ALG_TYPE_STREAM As Long = 2048 Private Const ALG_SID_RC4 As Long = 1 Private Const ALG_SID_MD5 As Long = 3 Private Const CALG_MD5 As Long = ((ALG_CLASS_HASH Or ALG_TYPE_ANY) Or ALG_SID_MD5) Private Const CALG_RC4 As Long = ((ALG_CLASS_DATA_ENCRYPT Or ALG_TYPE_STREAM) Or ALG_SID_RC4) Private Const ENCRYPT_ALGORITHM As Long = CALG_RC4 Private Const NUMBER_ENCRYPT_PASSWORD As String = "´o¸sçPQ]"

modCrypt.bas