The 'jsrsasign' (RSA-Sign JavaScript Library) is a open source free pure JavaScript implementation of PKCS#1 v2.1 RSASSA-PKCS1-v1_5 RSA signing and validation algorithm.
LICENSE
The 'jsrsasign'(RSA-Sign JavaScript Library) is licensed under the terms of the MIT license
reproduced which is simple and easy to understand and places almost no restrictions.