PayPal Mobile Payment Signature Problem

  node.js, question

In Alipay Mobile PaymentsignField RSA method

I am node.js development, this sign is to encrypt string or signature string?

The modules used arenode-rsa

Signature encryption string. Should be used firstSHA1The algorithm obtains the hash information of the parameters, and then carries out this informationRSAEncryption, many people think that onlyRSAEncryption, so I feel confused.