Visual FoxPro

Encrypt StringBuilder Content to a JWE

See more JSON Web Encryption (JWE) Examples

Demonstrates Jwe.EncryptSb, which encrypts content supplied in a StringBuilder and writes the resulting JWE into another StringBuilder.

Background. JWE (JSON Web Encryption) protects content with a content-encryption algorithm (the header enc value) while the content-encryption key is managed by the key-management algorithm (the header alg value). This example uses AES key wrapping with a symmetric wrapping key.

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LOCAL lnSuccess
LOCAL loJwe
LOCAL loHeader
LOCAL lcBase64Key
LOCAL loSbContent
LOCAL loSbJwe

lnSuccess = 0

loJwe = CreateObject('Chilkat.Jwe')

*  Set the JWE protected header, specifying the key-management algorithm (alg) and the content-
*  encryption algorithm (enc).
loHeader = CreateObject('Chilkat.JsonObject')
loHeader.UpdateString("alg","A256KW")
loHeader.UpdateString("enc","A256GCM")
lnSuccess = loJwe.SetProtectedHeader(loHeader)
IF (lnSuccess = 0) THEN
    ? loJwe.LastErrorText
    RELEASE loJwe
    RELEASE loHeader
    CANCEL
ENDIF

*  The 256-bit key-wrapping key (base64) for recipient index 0.  In production, obtain the key
*  from a secure source rather than hard-coding it.
lcBase64Key = "YWJjZGVmZ2hpamtsbW5vcHFyc3R1dnd4eXowMTIzNDU="
lnSuccess = loJwe.SetWrappingKey(0,lcBase64Key,"base64")
IF (lnSuccess = 0) THEN
    ? loJwe.LastErrorText
    RELEASE loJwe
    RELEASE loHeader
    CANCEL
ENDIF

*  Encrypt content supplied in a StringBuilder, writing the resulting JWE into another StringBuilder.
loSbContent = CreateObject('Chilkat.StringBuilder')
loSbContent.Append("This is the secret content.")

loSbJwe = CreateObject('Chilkat.StringBuilder')
lnSuccess = loJwe.EncryptSb(loSbContent,"utf-8",loSbJwe)
IF (lnSuccess = 0) THEN
    ? loJwe.LastErrorText
    RELEASE loJwe
    RELEASE loHeader
    RELEASE loSbContent
    RELEASE loSbJwe
    CANCEL
ENDIF

? loSbJwe.GetAsString()

RELEASE loJwe
RELEASE loHeader
RELEASE loSbContent
RELEASE loSbJwe