How to use RSA as kty jwk parameter (using jose4j)

Question

I am using jose4j to encrypt a String with JWE, following this documentation https://bitbucket.org/b_c/jose4j/wiki/JWE%20Examples

In the example, they used {"kty":"oct","k":"Fdh9u8rINxfivbrianbbVT1u232VQBZYKx1HGAGPt2I"}

It works well, but how to use RSA as kty ? Should I generate myself a key and put it in the "k" parameter ?

question from:https://stackoverflow.com/questions/65916936/how-to-use-rsa-as-kty-jwk-parameter-using-jose4j

Answer 1

no, a JWK representation of an RSA key has different parameters e.g.:

{
  "kty":"RSA",
  "n": "0vx7agoebGcQSuuPiLJXZptN9nndrQmbXEps2aiAFbWhM78LhWx
     4cbbfAAtVT86zwu1RK7aPFFxuhDR1L6tSoc_BJECPebWKRXjBZCiFV4n3oknjhMs
     tn64tZ_2W-5JsGY4Hc5n9yBXArwl93lqt7_RN5w6Cf0h4QyQ5v-65YGjQR0_FDW2
     QvzqY368QQMicAtaSqzs8KJZgnYb9c7d0zgdAZHzu6qMQvRL5hajrn1n91CbOpbI
     SD08qNLyrdkt-bFTWhAI4vMQFh6WeZu0fM4lFd2NcRwr3XPksINHaQ-G_xBniIqb
     w0Ls1jF44-csFCur-kEgU8awapJzKnqDKgw",
   "e":"AQAB",
   "alg":"RS256",
   "kid":"2011-04-29"
}

See RFC7517 : https://tools.ietf.org/html/rfc7517