account sign method allow binary data to be signed

In the Apostille Library NIP proposal, we found that nem2-sdk does not allow sign raw data.

we should add to Account class the next method:

class Account {
    // ...
    public signRaw(data:BinaryData | string): SignedBinary;
}

[khawarizmus]

if i am not mistaken (please correct me if i am wrong @aleixmorgadas ) the nem-sdk implementation of the sign function accepts the following types:

• BinaryKey
• Uint8Array
• string

it would be great to support all these types with signRaw() for nem2-sdk

Seems like BinaryKey is the same as Uint8Array, isn't it?

[khawarizmus]

No idea about that, sorry.

[khawarizmus]

@aleixmorgadas does this mean that we should create an interface for BinaryData ?

if so can you please share what you have in mind i am interested to do this

type SignedData = Uint8Array;

public signRaw(data: Uint8Array | string): SignedData {
    // ...
}

In the function, handle the type, if it's string, convert it to Uint8Array and then apply the signature method. Maybe you should add a new method called verify signature

#14

@gimyboya , when this PR is accepted, you will have the method signData in Account class

[khawarizmus]

Thanks @aleixmorgadas i have added Unit8Array support here #15
Also i think we need to support WordArray from crypto-js library which is different from Unit8Array