PureBasic

Manually Duplicate SetSecretKeyViaPassword

Demonstrates how to duplicate the password string to binary secret key computation of SetSecretKeyViaPassword.

This is a cryptographically weak way of generating a secret key from a password. The SetSecretKeyViaPassword method is deprecated and should not be used.

PureBasic

IncludeFile "CkCrypt2.pb"
IncludeFile "CkStringBuilder.pb"

Procedure ChilkatExample()

    ; This example assumes the Chilkat API to have been previously unlocked.
    ; See Global Unlock Sample for sample code.

    crypt.i = CkCrypt2::ckCreate()
    If crypt.i = 0
        Debug "Failed to create object."
        ProcedureReturn
    EndIf

    ; The password string is transformed to a binary secret key by computing the 
    ; MD5 digest (of the utf-8 password) to obtain 16 bytes.  
    ; If the KeyLength is greater than 16 bytes, then the MD5 digest of the Base64 encoding 
    ; of the utf-8 password is added.  A max of 32 bytes of key material is generated, and 
    ; this is truncated to the actual KeyLength required.

    CkCrypt2::setCkCryptAlgorithm(crypt, "aes")
    CkCrypt2::setCkKeyLength(crypt, 256)

    password.s = "this is my password"
    CkCrypt2::ckSetSecretKeyViaPassword(crypt,password)

    ; Examine the resulting SecretKey in hex:
    Debug "Computed Secret Key = " + CkCrypt2::ckGetEncodedKey(crypt,"hex")

    ; Now perform the same computation manually:
    sb.i = CkStringBuilder::ckCreate()
    If sb.i = 0
        Debug "Failed to create object."
        ProcedureReturn
    EndIf

    CkCrypt2::setCkHashAlgorithm(crypt, "md5")
    CkCrypt2::setCkCharset(crypt, "utf-8")
    CkCrypt2::setCkEncodingMode(crypt, "hex")
    CkStringBuilder::ckAppend(sb,CkCrypt2::ckHashStringENC(crypt,password))

    passwordBase64.s = CkCrypt2::ckEncodeString(crypt,password,"utf-8","base64")
    CkStringBuilder::ckAppend(sb,CkCrypt2::ckHashStringENC(crypt,passwordBase64))

    Debug "Manually Computed = " + CkStringBuilder::ckGetAsString(sb)

    ; The output is:
    ; Computed Secret Key = 210D53992DFF432EC1B1A9698AF9DA16C7E90518F90E24828F78EC9E0A413B36
    ; Manually Computed = 210D53992DFF432EC1B1A9698AF9DA16C7E90518F90E24828F78EC9E0A413B36


    CkCrypt2::ckDispose(crypt)
    CkStringBuilder::ckDispose(sb)


    ProcedureReturn
EndProcedure