Verifying signatures ? about vonage-java-code-snippets HOT 3 CLOSED

class NexmoSigner(val secretSigKey: String) {

    fun sign(sortedParams: TreeMap<String, String>): String {
        //adapted from https://github.com/Nexmo/nexmo-java/blob/master/src/main/java/com/nexmo/client/auth/RequestSigning.java

        // walk this sorted list of parameters and construct a string
        val sb = StringBuilder()
        for ((name, value) in sortedParams) {
            if (name == RequestSigning.PARAM_SIGNATURE) continue
            sb.append("&").append(clean(name)).append("=").append(clean(value))
        }
        // append the secret key and calculate an md5 signature of the resultant string
        sb.append(secretSigKey)

        val md5 = MD5Util.calculateMd5(sb.toString()
        return md5
    }

    private fun clean(str: String?): String? {
        return str?.replace("[=&]".toRegex(), "_")
    }
}

    protected fun verifyRequestSignature(req: NexmoDeliveryWebhookRequest): Boolean {
        val md5 = nexmoSigner.sign(TreeMap<String, String>().apply {
            put("status", req.status)
            put("messageId", req.messageId)
            put("sig", req.sig) //will be excluded automatically
            put("timestamp", req.timestamp)
            put("err-code", req.errCode)
            put("message-timestamp", req.messageTimestamp)
            put("msisdn", req.msisdn)
            put("network-code", req.networkCode)
            put("price", req.price)
            put("scts", req.scts)
            put("to", req.to)
            put("nonce", req.nonce)
        })

        // verify that the supplied signature matches generated one
        return md5 == req.sig
    }

//see https://developer.nexmo.com/messaging/sms/guides/delivery-receipts and https://developer.nexmo.com/api/sms#delivery-receipt
data class NexmoDeliveryWebhookRequest(
        val status: String = "",
        val messageId: String = "",
        val sig: String = "",
        val timestamp: String = "",
        @SerializedName("err-code") val errCode: String = "",
        @SerializedName("message-timestamp") val messageTimestamp: String = "",
        val msisdn: String = "",
        @SerializedName("network-code") val networkCode: String = "",
        val price: String = "",
        val scts: String = "",
        val to: String = "",
        val nonce: String = "" //!\ undocumented in the Nexmo guide and API doc !!!
)