bytearray - SHA-512 hashing a byte array in ColdFusion

Question

I am using ColdFusion 9

Referencing Ben Nadel's good works on his blog, I tried

ucase(digestUtils.sha512(imageBinary))

For SHA-512 hashing I get that dreaded:

The sha512 method was not found. Either there are no methods with the specified method name and argument types or the sha512 method is overloaded with argument types that ColdFusion cannot decipher reliably. ColdFusion found 0 methods that match the provided arguments. If this is a Java object and you verified that the method exists, use the javacast function to reduce ambiguity.

Now I know that sha512 does indeed exist as a method, because I saw it here, but when I perform a

cfdump var="#digestUtils#"

I only get:

md5(byte[])     byte[]
md5(java.lang.String)   byte[]
md5Hex(byte[])  java.lang.String
md5Hex(java.lang.String)    java.lang.String
sha(java.lang.String)   byte[]
sha(byte[])     byte[]
shaHex(java.lang.String)    java.lang.String
shaHex(byte[])  java.lang.String

What happened to the other methods? I guess I have to try something else.

Please advise with a ColdFusion solution. A ColdFusion/Java solution would be ok too. I'm trying to write a SSO application where the 3rd party guys feeds me URL parameters. I have successfully decoded the 1st parameter to get my XML Post. I now need to take the 2nd parameter which is the hash payload and go through the algorithm to ensure my 1st parameter hasn't been tampered with.

========= Editing begins here: Okay,I tried writing the code again to no avail.

The algorithm sounds simple enough. But trying to implement it is killing me.

1. compute the hash string value of the XMLPost string above:
 a. convert the base64 salt string to a UTF-8 byte array.
 b. convert the base64 XML payload string to a UTF-8 byte array.
 c. create a new byte array consisting of the XML payload bytes from step b, appended with the salt bytes from step a.
 d. perform a SHA512 hash on the concatenated byte array from step c, which results in a hashed byte array.
 e. create a new byte array consisting of the hashed bytes from step d, appended with the salt bytes from step a.
 f. convert the result of step e to a base64-encoded string and should be the value of query string parameter "h" payload hash.

xmlPost was created by my third party guys as such: This XML payload string was converted to a UTF-8 byte array, which was then converted to a base-64 string. The resulting base-64 string is the value of my xmlPost below.

So I do this:

<code>
<cfset xmlPost = urlDecode("PD94bWwgdmVyc2lvbj0iMS4wIj8%2bPEVzdG9yZVNzb0N1c3RvbWVyIHhtbG5zOnhzaT0iaHR0cDovL3d3dy53My5vcmcvMjAwMS9YTUxTY2hlbWEtaW5zdGFuY2UiIHhtbG5zOnhzZD0iaHR0cDovL3d3dy53My5vcmcvMjAwMS9YTUxTY2hlbWEiPjxDdXN0b21lcklkPjExMjk0MDwvQ3VzdG9tZXJJZD48RGVhbGVyQ29kZT5OODg4ODg8L0RlYWxlckNvZGU%2bPFBvaW50QmFsYW5jZT4yODA8L1BvaW50QmFsYW5jZT48Rmlyc3ROYW1lPkZhaXRoPC9GaXJzdE5hbWU%2bPExhc3ROYW1lPkh1dHVsYTwvTGFzdE5hbWU%2bPC9Fc3RvcmVTc29DdXN0b21lcj4%3d") />
<cfset salt = "3dfjh674!MujErf98344@090" />
<cfset payload_hash = urlDecode("EtLDRJfcRESFKpY4OGZZnRSN2THqT%2bEelzOuXVU06jotd2kE4yKnlYay7BqyAdcUSATRgSMaHxZa6uBqKKd9rjNkZmpoNjc0IU11akVyZjk4MzQ0QDA5MA%3d%3d") />

<cfset strXML = ToString( ToBinary( xmlpost ) ) /> <!--- to get actual XML --->

<!--- base64 encoding returns a byte array --->
<cfset saltByteArray = toBase64( salt, "utf-8" )  /> 
<cfset xmlpostByteArray = toBase64( xmlPost, "utf-8" ) />
<!--- append salt to xmlpost --->
<cfset xmlpostsaltByteArray = xmlpostByteArray & saltByteArray />

<!--- now let us perform a sha512 hash on this concatenated byte array --->
<cfscript>
// Create an instance of our DigestUtils class
digestUtils = createObject("java","org.apache.commons.codec.digest.DigestUtils");
// I hash a byte array using the given algorithm and return a
// 32-character Hexadecimal string. Home-made hash function for CF9 and earlier
function hashBytes( bytes, algorithm = "SHA-512" ){
    // Get our instance of the digest algorithm that we'll use
    // to hash the byte array.
    var messageDigest = createObject( "java", "java.security.MessageDigest" ).getInstance( javaCast( "string", algorithm ) );

    // Get the digest for the given byte array. This returns the
    // digest (i.e., hash) in byte-array format.
    var digest = messageDigest.digest( bytes );

    // Now that we have our digested byte array (i.e., our hash as another byte
    // array), we have to convert that into a HEX string. So, we'll need a HEX buffer.
    var hexBuffer = [];

    // Each integer in the byte digest needs to be converted into
    // a HEX character (with possible leading zero).
    for (byte =1 ;byte LTE ArrayLen(digest);byte = byte + 1) {
    //for ( var byte in digest){
        // Get the hex value for this byte. When converting the
        // byte, only use the right-most 8 bits (last 8 bits of the integer)
        // otherwise the sign of the byte can create oddities

        var tail = bitAnd( 255, byte );

        // Get the hex-encoding of the byte.
        var hex = ucase( formatBaseN( tail, 16 ) );

        // In order to make sure that all of the HEX characters
        // are two-digits, we have to prepend a zero for any
        // value that was originally LTE to 16 (the largest value
        // that won't result in two HEX characters).
        arrayAppend( hexBuffer, (tail <= 16 ? ("0" & hex) : hex) );
    }

    // Return the flattened character buffer.
    return( arrayToList( hexBuffer, "" ) );
}

// Get the hash of the byte array using our hashBytes() function
hashByteArray = hashBytes( xmlpostsaltByteArray );  
</cfscript>


<!--- The hashByteArray is in HEX format now. Convert to binary --->
<!--- You must binary decode the hashed string before converting it to binary --->
<cfset hashByteArray = toBase64( BinaryDecode( hashByteArray, 'HEX' ) ) />

<!--- The final step is to append this new hashbytearray with the salt byte array --->

<cfset hashByteArray = hashByteArray & saltByteArray />

<!--- now convert this value to a base64 encoded string --->

<cfset hashByteArray2 = toBase64( hashByteArray )/>

Here is what I get for my strXML variable:

Actual xml structure converted from base 64 to string:
<?xml version="1.0"?><EstoreSsoCustomer xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema"><CustomerId>112940</CustomerId><DealerCode>N88888</DealerCode><PointBalance>280</PointBalance><FirstName>Faith</FirstName><LastName>Hutula</LastName></EstoreSsoCustomer>  

The final value, hasByteArray2 is not even remotely similar to payload_hash

This is my first time doing this and my understanding of hashing, byte arrays and character conversions flew out of the window decades ago.

What am I doing wrong?

Thank you Faith Sloan

Answer 1

DigestUtils.sha512 was added in version 1.4. ColdFusion 9 uses an older version, 1.3. That is why the method is not found.

Use the other function based on MessageDigest. Just be sure to pass in the correct algorithm ie:

    imageHash = hashBytes( imageBinary, "SHA-512" );

---

UPDATE: Based on the updated code, some of the instructions may be a bit misleading. I believe they just mean decode the xml and salt strings from their given encoding (base64 and utf-8) into byte arrays, not strings:

    // note: salt value has invalid characters for base64
    // assuming it is a plain utf-8 string
    saltArray = charsetDecode(salt, "utf-8");
    xmlByteArray = binaryDecode(xmlPost, "base64");

Then merge the two binary arrays (see custom function)

    mergedBytes = mergeArrays( xmlByteArray, saltArray );

Calculate the hash of the new byte array:

    messageDigest = createObject( "java", "java.security.MessageDigest" );
    messageDigest = messageDigest.getInstance( javaCast( "string", "SHA-512") );
    hashedByteArray = messageDigest.digest( javacast("byte[]", mergedBytes) );

Merge the arrays again:

    mergedBytes = mergeArrays( hashedByteArray, saltArray);

Finally convert the binary to base64 and compare:

    calculatedPayload = binaryEncode( javacast("byte[]", mergedBytes), "base64");

    // check results
    arePayloadsEqual = compare(calculatedPayload, payload_hash) eq 0;
    WriteDump("arePayloadsEqual="& arePayloadsEqual);
    WriteDump("calculatedPayload="& calculatedPayload);
    WriteDump("payload_hash="& payload_hash);

Note: BinaryDecode/CharsetDecode return java arrays. Unlike CF arrays, they are immutable (ie cannot be changed). So the handy addAll(..) trick will not work here.

    // merge immutable arrays the long way
    function mergeArrays( array1, array2 ){
        var i = 0;
        var newArray = [];
        for (i = 1; i <= arrayLen(arguments.array1); i++) {
            arrayAppend(newArray, arguments.array1[i]);
        }
        for (i = 1; i <= arrayLen(arguments.array2); i++) {
            arrayAppend(newArray, arguments.array2[i]);
        }
        return newArray;
    }