Visual FoxPro

Load a JWE from a StringBuilder

See more JSON Web Encryption (JWE) Examples

Demonstrates Jwe.LoadJweSb, which loads a JWE from a StringBuilder (here read from a file) so it can be decrypted.

The file path is relative to the application's current working directory. An absolute path may also be used. Supply the path appropriate to your own environment.

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 loSbJwe
LOCAL lnBLoaded
LOCAL lcBase64Key
LOCAL lcContent

lnSuccess = 0

loJwe = CreateObject('Chilkat.Jwe')

*  The file path is relative to the application's current working directory.  An absolute path may
*  also be used.  Supply the path appropriate to your own environment.

*  Load the JWE text from a file into a StringBuilder.
loSbJwe = CreateObject('Chilkat.StringBuilder')
lnBLoaded = loSbJwe.LoadFile("qa_data/message.jwe","utf-8")
IF (lnBLoaded <> 1) THEN
    ? "Failed to load the JWE file."
    RELEASE loJwe
    RELEASE loSbJwe
    CANCEL
ENDIF

*  Load the JWE from the StringBuilder.
lnSuccess = loJwe.LoadJweSb(loSbJwe)
IF (lnSuccess = 0) THEN
    ? loJwe.LastErrorText
    RELEASE loJwe
    RELEASE loSbJwe
    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 loSbJwe
    CANCEL
ENDIF

lcContent = loJwe.Decrypt(0,"utf-8")
IF (loJwe.LastMethodSuccess = 0) THEN
    ? loJwe.LastErrorText
    RELEASE loJwe
    RELEASE loSbJwe
    CANCEL
ENDIF

? lcContent

RELEASE loJwe
RELEASE loSbJwe