HMAC SHA1 ColdFusion

Question

Please help! I have been pulling out my hair over this one. :)

I have a site that I need to HMAC SHA1 for authentication. It currently works with another language

Answer 1

A shorter encryption method (based on Barney's method) that outputs a string:

<cffunction name="CFHMAC" output="false" returntype="string">
   <cfargument name="signMsg" type="string" required="true" />
   <cfargument name="signKey" type="string" required="true" />
   <cfargument name="encoding" type="string" default="utf-8" />
   <cfset var key = createObject("java", "javax.crypto.spec.SecretKeySpec").init(signKey.getBytes(arguments.encoding), "HmacSHA1") />
   <cfset var mac = createObject("java", "javax.crypto.Mac").getInstance("HmacSHA1") />
   <cfset mac.init(key) />
   <cfreturn toBase64(mac.doFinal(signMsg.getBytes(arguments.encoding))) />
</cffunction>

In addition

1. ColdFusion 10 supports HMAC-SHA1 for Encrypting and Hashing natively.
2. There is a library called CF_HMAC distributed by Adobe
3. There are several libraries that deal with HMAC in relation while signing files for Amazon. Among them are cf-amazon-s3, Barney's S3 URL Builder, and RIAForge S3

Answer 2

Doing an HMAC-SHA1 thing myself. Best I can say is that I found this old function. Has worked great for what I am doing thus far. Forgot where I found it though so I can't credit the author.

For your Base 64 stuff... run this function on your encryption, then just do a cfset newString = toBase64(oldString) on what is returned.

<cffunction name="hmacEncrypt" returntype="binary" access="public" output="false">
   <cfargument name="signKey" type="string" required="true" />
   <cfargument name="signMessage" type="string" required="true" />
   <cfargument name="algorithm" type="string" default="HmacSHA1" />
   <cfargument name="charset" type="string" default="UTF-8" />

   <cfset var msgBytes = charsetDecode(arguments.signMessage, arguments.charset) />
   <cfset var keyBytes = charsetDecode(arguments.signKey, arguments.charset) />
   <cfset var keySpec = createObject("java","javax.crypto.spec.SecretKeySpec")  />
   <cfset var mac = createObject("java","javax.crypto.Mac") />

   <cfset key = keySpec.init(keyBytes, arguments.algorithm) />
   <cfset mac = mac.getInstance(arguments.algorithm) />
   <cfset mac.init(key) />
   <cfset mac.update(msgBytes) />

   <cfreturn mac.doFinal() />
</cffunction>

Answer 3

Steve - Thanks for your response. I actually was using the hmacEncrypt function already. I did figure out my issue though. I was passing in a HEX key instead of a string. It accepted the key because technically it was a string. To get it back to a string I used another function along with the one above. The one below changes the HEX into a string. I didn't write the function below nor do I remember where it came from to get the author credit, but it worked great.

<cffunction name="Hex2Bin" returntype="any" hint="Converts a Hex string to binary">
    <cfargument name="inputString" type="string" required="true" hint="The hexadecimal string to be written.">
    <cfset var outStream = CreateObject("java", "java.io.ByteArrayOutputStream").init()>
    <cfset var inputLength = Len(arguments.inputString)>
    <cfset var outputString = "">
    <cfset var i = 0>
    <cfset var ch = "">
    <cfif inputLength mod 2 neq 0>
    <cfset arguments.inputString = "0" & inputString>
    </cfif>
    <cfloop from="1" to="#inputLength#" index="i" step="2">
        <cfset ch = Mid(inputString, i, 2)>
        <cfset outStream.write(javacast("int", InputBaseN(ch, 16)))>
    </cfloop>
    <cfset outStream.flush()>
    <cfset outStream.close()> 
    <cfreturn outStream.toByteArray()>
</cffunction>