Key Encryption (RSAES)

Key Encryption with RSAES uses a kind of "reverse" encryption. In this mode, the holder of the private key is the recipient, not the producer. The recipient shares a public key, that the producer can use to encrypt the CEK. Then, only the recipient with the private key will be able to decrypt the CEK and access the payload.

package main

import (
	"crypto/rsa"
	"github.com/a-novel-kit/jwt/jwe/jwek"
)

func main() {
	// The private key used to decrypt the message. The public
	// version of this key MUST have been shared to
	// the producer, ahead of the token creation.
	var privateKey *rsa.PrivateKey

	keyDecoder := jwek.NewRSAOAEPKeyEncDecoder(
		&jwek.RSAOAEPKeyEncDecoderConfig{EncKey: privateKey},
        jwek.RSAOAEP256,
	)
}

Available presets:

Preset	Target "alg"
⚠️ jwek.RSAOAEP	RSA-OAEP
jwek.RSAOAEP256	RSA-OAEP-256

Caution

RSA-OAEP without sha256 is deprecated, as it relies on the broken SHA1 algorithm. It is still available for compatibility reasons, but should not be used in new applications.

See this post for explanation