B4X

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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Dim success As Boolean = False

Dim jwe As ChilkatJwe
jwe.Initialize

'  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.
Dim sbJwe As ChilkatStringBuilder
sbJwe.Initialize
Dim bLoaded As Boolean = sbJwe.LoadFile("qa_data/message.jwe", "utf-8")
If bLoaded <> True Then
    Log("Failed to load the JWE file.")
    Return
End If


'  Load the JWE from the StringBuilder.
success = jwe.LoadJweSb(sbJwe)
If success = False Then
    Log(jwe.LastErrorText)
    Return
End If


'  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.
Dim base64Key As String = "YWJjZGVmZ2hpamtsbW5vcHFyc3R1dnd4eXowMTIzNDU="
success = jwe.SetWrappingKey(0, base64Key, "base64")
If success = False Then
    Log(jwe.LastErrorText)
    Return
End If


Dim content As String = jwe.Decrypt(0, "utf-8")
If jwe.LastMethodSuccess = False Then
    Log(jwe.LastErrorText)
    Return
End If

Log(content)