B4X

JWE using ECDH-ES, BP-256, A256GCM

See more JSON Web Encryption (JWE) Examples

Create a JWE with the following header:

	{
	  "alg": "ECDH-ES",
	  "enc": "A256GCM",
	  "exp": 1621957030,
	  "cty": "NJWT",
	  "epk": {
	    "kty": "EC",
	    "x": "QLpJ_LpFx-6yJhsb4OvHwU1khLnviiOwYOvmf5clK7w"
	    "y": "AJh7pJ3zZKDJkm8rbeG69GBooTosXJgSsvNFH0i3Vxnu"
	    "crv": "BP-256"
	  }
	}

Note: This example requires Chilkat v9.5.0.87 or greater.

B4X

Dim success As Boolean = False

'  This requires the Chilkat API to have been previously unlocked.
'  See Global Unlock Sample for sample code.

'  Load our brainpool BP-256 public key.

'  	{
'  	  "use": "enc",
'  	  "kid": "puk_idp_enc",
'  	  "kty": "EC",
'  	  "crv": "BP-256",
'  	  "x": "QLpJ_LpFx-6yJhsb4OvHwU1khLnviiOwYOvmf5clK7w",
'  	  "y": "AJh7pJ3zZKDJkm8rbeG69GBooTosXJgSsvNFH0i3Vxnu"
'  	}

Dim json As ChilkatJsonObject
json.Initialize
json.UpdateString("use", "enc")
json.UpdateString("kid", "puk_idp_enc")
json.UpdateString("kty", "EC")
json.UpdateString("crv", "BP-256")
json.UpdateString("x", "QLpJ_LpFx-6yJhsb4OvHwU1khLnviiOwYOvmf5clK7w")
json.UpdateString("y", "AJh7pJ3zZKDJkm8rbeG69GBooTosXJgSsvNFH0i3Vxnu")

Dim pubkey As ChilkatPublicKey
pubkey.Initialize

success = pubkey.LoadFromString(json.Emit)
If success = False Then
    Log(pubkey.LastErrorText)
    Return
End If


'  Build our protected header:

'  	{
'  	  "alg": "ECDH-ES",
'  	  "enc": "A256GCM",
'  	  "exp": 1621957030,
'  	  "cty": "NJWT",
'  	  "epk": {
'  	    "kty": "EC",
'  	    "x": "QLpJ_LpFx-6yJhsb4OvHwU1khLnviiOwYOvmf5clK7w"
'  	    "y": "AJh7pJ3zZKDJkm8rbeG69GBooTosXJgSsvNFH0i3Vxnu"
'  	    "crv": "BP-256"
'  	  }
'  	}

'  Use jwt only for getting the current date/time + 3600 seconds.
Dim jwt As ChilkatJwt
jwt.Initialize

Dim jweProtHdr As ChilkatJsonObject
jweProtHdr.Initialize
jweProtHdr.UpdateString("alg", "ECDH-ES")
jweProtHdr.UpdateString("enc", "A256GCM")
jweProtHdr.UpdateInt("exp", jwt.GenNumericDate(3600))
jweProtHdr.UpdateString("cty", "NJWT")
jweProtHdr.UpdateString("epk.kty", "EC")
jweProtHdr.UpdateString("epk.x", "QLpJ_LpFx-6yJhsb4OvHwU1khLnviiOwYOvmf5clK7w")
jweProtHdr.UpdateString("epk.y", "AJh7pJ3zZKDJkm8rbeG69GBooTosXJgSsvNFH0i3Vxnu")
jweProtHdr.UpdateString("epk.crv", "BP-256")

Dim jwe As ChilkatJwe
jwe.Initialize
jwe.SetProtectedHeader(jweProtHdr)
jwe.SetPublicKey(0, pubkey)

Dim plainText As String = "This is the text to be encrypted."
Dim strJwe As String = jwe.Encrypt(plainText, "utf-8")
If jwe.LastMethodSuccess <> True Then
    Log(jwe.LastErrorText)
    Return
End If


Log(strJwe)

Log("Success.")