Xbase++

JWE using A256GCMKW

See more JSON Web Encryption (JWE) Examples

This example demonstrates creating a JCE with AES GCM key wrap. Xbase++

LOCAL nSuccess
LOCAL cPlaintext
LOCAL oJwe
LOCAL oJweProtHdr
LOCAL oPrng
LOCAL cAesWrappingKey
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.

cPlaintext := "My text to enrypt"

oJwe := CreateObject("Chilkat.Jwe")

//  First build the JWE Protected Header: 

//          {
//              "alg": "A256GCMKW",
//              "kid": "18ec08e1-bfa9-4d95-b205-2b4dd1d4321d",
//              "tag": "kfPduVQ3T3H6vnewt--ksw",
//              "iv": "KkYT0GX_2jHlfqN_",
//              "enc": "A128CBC-HS256"
//          }

oJweProtHdr := CreateObject("Chilkat.JsonObject")
oJweProtHdr:AppendString("alg", "A256GCMKW")
//  kid is optional
oJweProtHdr:AppendString("kid", "18ec08e1-bfa9-4d95-b205-2b4dd1d4321d")
//  tag is optional
oJweProtHdr:AppendString("tag", "kfPduVQ3T3H6vnewt--ksw")
oJweProtHdr:AppendString("enc", "A256GCM")
//  the iv should be 16 random chars.
oPrng := CreateObject("Chilkat.Prng")
oJweProtHdr:AppendString("iv", oPrng:RandomString(16, 1, 1, 1))
oJwe:SetProtectedHeader(oJweProtHdr)

? "JWE Protected Header: " + oJweProtHdr:Emit()
? "--"

//  Given that we have 256-bit AES, our key should be 32 bytes.
//  The ascii string here is 32 bytes, therefore the 2nd arg is "ascii" to use these
//  ascii chars directly as the key.
cAesWrappingKey := "2baf4f730f5e4542b428593ef9cceb0e"
oJwe:SetWrappingKey(0, cAesWrappingKey, "ascii")

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

//  Show the JWE we just created:
? cStrJwe

//  Decrypt the JWE that was just produced.
//  1) Load the JWE.
//  2) Set the AES wrapping key.
//  3) Decrypt.
oJwe2 := CreateObject("Chilkat.Jwe")
nSuccess := oJwe2:LoadJwe(cStrJwe)
IF (nSuccess != 1)
    ? oJwe2:LastErrorText
    oJwe:destroy()
    oJweProtHdr:destroy()
    oPrng:destroy()
    oJwe2:destroy()
    RETURN
ENDIF

//  Set the AES wrap key.  Important to use "ascii"
oJwe2:SetWrappingKey(0, cAesWrappingKey, "ascii")

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

? "original text: "
? cOriginalPlaintext

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