HMAC

Generate new key

Creating Gen Spec

Following the below compatibility table you can create a new HMAC key:

Digest	Key size
SHA1	S192
SHA256	S256
SHA384	S384
SHA512	S512, S1024

Note

The key sizes listed are suggested for use with the indicated SHA values, but this depends on your implementation, as there are no strict requirements for the key size in HMAC

val keyGenSpec = SymmetricKeyGenSpec(
    keySize = S256
)

Declaring the purposes of the key

The generating key will be used just for the specified purposes, when a purpose had not been assigned will be thrown an exception

val purposes = KeyPurposes(
    canSign = true,
    canVerify = true
)

Generate the key

KassaforteSymmetricService.generateKey(
    alias = "toIdentifyTheKey",
    algorithm = Algorithm.HMAC_SHA256,
    keyGenSpec = keyGenSpec,
    purposes = purposes
)

The generated key will be automatically securely stored by the library

Use the key

The methods which use the key must be executed inside a Coroutine

Sign

val scope = MainScope()
scope.launch {
    // data to sign
    val message = "My message"

    // sign the message 
    val signedMessage = KassaforteSymmetricService.sign(
        alias = "toIdentifyTheKey",
        message = data
    )

    println(signedMessage)
}

Verify

val scope = MainScope()
scope.launch {
    // data to verify
    val messageToVerify = "My message"

    // signature
    val signedMessage = "...signed message.."

    // verify the data 
    val result = KassaforteSymmetricService.verify(
        alias = "toIdentifyTheKey",
        message = messageToVerify,
        signature = signedMessage
    )

    println(result) // true or false
}

Delete a key

KassaforteSymmetricService.deleteKey(
    alias = "toIdentifyTheKey"
)

The key will be removed from the secure storage and will not more available to be used