title: How to encrypt and decrypt using ECDSA private key and public key generated in Hyperledger fabric
body: <p>I am working on a basic-network project on <strong>Hyperledeger Fabric V-1.4.1</strong>. I have enrolled an admin and created a user using <strong>enrollAdmin.js</strong> and <strong>registerUser.js</strong>. A <strong>public Key</strong> and a <strong>private key</strong> is generated for <strong>user1</strong>. Now I want to use that <strong>private key</strong> to <strong>sign</strong> simple data and later <strong>verify</strong> using the <strong>public Key</strong>. I have tried using <strong>URSA</strong> node module which works fine with RSA keys generated through <strong>OpenSSL</strong> but isn't working with these two keys. Probably because these keys are not <strong>RSA</strong>, they are <strong>ECDSA</strong> keys. I have also read the documentation of the <strong>Crypto</strong> node module and it seems I need to have <strong>.pem</strong> files as keys to use in <strong>Crypto</strong> module. But In fabric, I have key files as <strong>-priv</strong> and <strong>-pub</strong> format.
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  Is there any node module that can encrypt decrypt using <strong>ECDSA</strong> keys?
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  Is there any specific way in hyperledger fabric to do this?
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  Or is there any other way I can do this thing?<br> Please ask any questions if necessary.<br>
  Thank you.</p>