Xbase++

JWE using "dir" Direct use of Shared Symmetric Key

See more JSON Web Encryption (JWE) Examples

Demonstrates how to create a JWE using the "dir" alg -- which is to directly use a shared symmetric key.

Note: This example requires Chilkat v9.5.0.66 or greater.

Xbase++

LOCAL nSuccess
LOCAL cPlaintext
LOCAL oJwe
LOCAL oJweProtHdr
LOCAL nRecipientIndex
LOCAL cStrJwe
LOCAL oJwe2
LOCAL cOriginalPlaintext

nSuccess := 0

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

//  Note: This example requires Chilkat v9.5.0.66 or greater.

cPlaintext := "Live long and prosper."

oJwe := CreateObject("Chilkat.Jwe")

//  First build the JWE Protected Header..
oJweProtHdr := CreateObject("Chilkat.JsonObject")
oJweProtHdr:AppendString("alg", "dir")
oJweProtHdr:AppendString("enc", "A128GCM")

//  Don't forget to actually provide the protected header to the JWE object:
oJwe:SetProtectedHeader(oJweProtHdr)

//  The JWE is to use 128-bit AES GCM encryption as specified by the "enc" parameter.
//  Given that the "alg" = "dir", we are to directly specify the AES GCM key.
//  (It is assumed that the decrypting side also has knowledge of the direct key to be used..)

//  Our key will be these 16 hex bytes: 000102030405060708090A0B0C0D0E0F

//  The SetWrappingKey method is also used for "dir" direct keys.
//  However, if there are multiple recipients, they must all share the same CEK (Content Encryption Key),
//  which is specified by calling SetWrappingKey with an index of 0.

nRecipientIndex := 0
oJwe:SetWrappingKey(nRecipientIndex, "000102030405060708090A0B0C0D0E0F", "hex")

//  Encrypt and return the JWE:
cStrJwe := oJwe:Encrypt(cPlaintext, "utf-8")
IF (oJwe:LastMethodSuccess != 1)
    ? oJwe:LastErrorText
    oJwe:destroy()
    oJweProtHdr:destroy()
    RETURN
ENDIF

//  Show the JWE we just created:
? cStrJwe

//  Decrypt the JWE.
oJwe2 := CreateObject("Chilkat.Jwe")
nSuccess := oJwe2:LoadJwe(cStrJwe)
IF (nSuccess != 1)
    ? oJwe2:LastErrorText
    oJwe:destroy()
    oJweProtHdr:destroy()
    oJwe2:destroy()
    RETURN
ENDIF

oJwe2:SetWrappingKey(0, "000102030405060708090A0B0C0D0E0F", "hex")

//  Decrypt.
cOriginalPlaintext := oJwe2:Decrypt(0, "utf-8")
IF (oJwe2:LastMethodSuccess != 1)
    ? oJwe2:LastErrorText
    oJwe:destroy()
    oJweProtHdr:destroy()
    oJwe2:destroy()
    RETURN
ENDIF

? "original text: "
? cOriginalPlaintext

//  Sample output:
//  eyJhbGciOiJkaXIiLCJlbmMiOiJBMTI4R0NNIn0..20HX5Huc7f1nQC4pBUtiCQ.axFZIxtZy5j0ifJQUzGXLKIpsBuxJA.eBrOC-NrsreN6JeGuOPk1g
//  original text: 
//  Live long and prosper.

oJwe:destroy()
oJweProtHdr:destroy()
oJwe2:destroy()