PureBasic

Decrypt a JWE into a StringBuilder

See more JSON Web Encryption (JWE) Examples

Demonstrates Jwe.DecryptSb, which decrypts a recipient of a loaded JWE and writes the plaintext into a StringBuilder.

Background. The recipient index selects which recipient's key material to use. The key for that recipient must be provided before decrypting.

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IncludeFile "CkStringBuilder.pb"
IncludeFile "CkJwe.pb"

Procedure ChilkatExample()

    success.i = 0

    jwe.i = CkJwe::ckCreate()
    If jwe.i = 0
        Debug "Failed to create object."
        ProcedureReturn
    EndIf

    ;  Load the JWE compact serialization to be decrypted.
    jweCompact.s = "eyJhbGciOiJBMjU2S1ciLCJlbmMiOiJBMjU2R0NNIn0.<...>.<iv>.<ciphertext>.<tag>"
    success = CkJwe::ckLoadJwe(jwe,jweCompact)
    If success = 0
        Debug CkJwe::ckLastErrorText(jwe)
        CkJwe::ckDispose(jwe)
        ProcedureReturn
    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.
    base64Key.s = "YWJjZGVmZ2hpamtsbW5vcHFyc3R1dnd4eXowMTIzNDU="
    success = CkJwe::ckSetWrappingKey(jwe,0,base64Key,"base64")
    If success = 0
        Debug CkJwe::ckLastErrorText(jwe)
        CkJwe::ckDispose(jwe)
        ProcedureReturn
    EndIf

    ;  Decrypt recipient index 0, writing the plaintext into a StringBuilder.
    sbContent.i = CkStringBuilder::ckCreate()
    If sbContent.i = 0
        Debug "Failed to create object."
        ProcedureReturn
    EndIf

    success = CkJwe::ckDecryptSb(jwe,0,"utf-8",sbContent)
    If success = 0
        Debug CkJwe::ckLastErrorText(jwe)
        CkJwe::ckDispose(jwe)
        CkStringBuilder::ckDispose(sbContent)
        ProcedureReturn
    EndIf

    Debug CkStringBuilder::ckGetAsString(sbContent)


    CkJwe::ckDispose(jwe)
    CkStringBuilder::ckDispose(sbContent)


    ProcedureReturn
EndProcedure