Xbase++

JWE with DEFLATE Compression

See more JSON Web Encryption (JWE) Examples

Demonstrates how to DEFLATE ("zip") compress the JWE payload prior to encryption.

Note: This example requires Chilkat v9.5.0.66 or greater.

Xbase++

LOCAL nSuccess
LOCAL oSbPlainText
LOCAL nBCrLf
LOCAL cLine
LOCAL oJwe
LOCAL oJweProtHdr
LOCAL cAesWrappingKey
LOCAL oSbJweCompressed
LOCAL oSbJweUncompressed
LOCAL oJwe2
LOCAL oSbOriginalText

nSuccess := 0

//  This requires the Chilkat API to have been previously unlocked.
//  See Global Unlock Sample for sample code.

//  Note: This example requires Chilkat v9.5.0.66 or greater.

//  Create some plaintext to be encrypted.
//  This example will demonstrate with and without DEFLATE (zip) compression.
oSbPlainText := CreateObject("Chilkat.StringBuilder")
nBCrLf := 1
cLine := "Live long and prosper."
oSbPlainText:AppendLine(cLine, nBCrLf)
oSbPlainText:AppendLine(cLine, nBCrLf)
oSbPlainText:AppendLine(cLine, nBCrLf)
oSbPlainText:AppendLine(cLine, nBCrLf)

//  The text to be encrypted:
? oSbPlainText:GetAsString()

oJwe := CreateObject("Chilkat.Jwe")

//  Build the JWE Protected Header: {"alg":"A128KW","enc":"A128CBC-HS256","zip":"DEF"}
//  The "zip":"DEF" parameter indicates that the plaintext payload should
//  be compressed prior to encryption.
oJweProtHdr := CreateObject("Chilkat.JsonObject")
oJweProtHdr:AppendString("alg", "A128KW")
oJweProtHdr:AppendString("enc", "A128CBC-HS256")
oJweProtHdr:AppendString("zip", "DEF")
oJwe:SetProtectedHeader(oJweProtHdr)

//  Set the AES key wrap key:
cAesWrappingKey := "GawgguFyGrWKav7AX4VKUg"
oJwe:SetWrappingKey(0, cAesWrappingKey, "base64url")

//  Encrypt and return the JWE in sbJweCompressed:
oSbJweCompressed := CreateObject("Chilkat.StringBuilder")
nSuccess := oJwe:EncryptSb(oSbPlainText, "utf-8", oSbJweCompressed)
IF (nSuccess != 1)
    ? oJwe:LastErrorText
    oSbPlainText:destroy()
    oJwe:destroy()
    oJweProtHdr:destroy()
    oSbJweCompressed:destroy()
    RETURN
ENDIF

//  Show the compressed JWE:
? oSbJweCompressed:GetAsString()
? "size of compressed JWE: " + Str(oSbJweCompressed:Length)

//  Now create a JWE without compression.
oJweProtHdr:Delete("zip")
//  Make sure to update the shared protected header:
oJwe:SetProtectedHeader(oJweProtHdr)

oSbJweUncompressed := CreateObject("Chilkat.StringBuilder")
nSuccess := oJwe:EncryptSb(oSbPlainText, "utf-8", oSbJweUncompressed)
IF (nSuccess != 1)
    ? oJwe:LastErrorText
    oSbPlainText:destroy()
    oJwe:destroy()
    oJweProtHdr:destroy()
    oSbJweCompressed:destroy()
    oSbJweUncompressed:destroy()
    RETURN
ENDIF

//  Show the uncompressed JWE:
? oSbJweUncompressed:GetAsString()
? "size of uncompressed JWE: " + Str(oSbJweUncompressed:Length)

//  Decrypting is the same whether compression is used or not.
//  The "zip" header in the JWE indicates that the payload should be 
//  automatically decompressed (inflated) after decrypting.
oJwe2 := CreateObject("Chilkat.Jwe")
nSuccess := oJwe2:LoadJweSb(oSbJweCompressed)
IF (nSuccess != 1)
    ? oJwe2:LastErrorText
    oSbPlainText:destroy()
    oJwe:destroy()
    oJweProtHdr:destroy()
    oSbJweCompressed:destroy()
    oSbJweUncompressed:destroy()
    oJwe2:destroy()
    RETURN
ENDIF

//  Set the AES wrap key.
oJwe2:SetWrappingKey(0, cAesWrappingKey, "base64url")

//  Decrypt (also automatically decompresses).
oSbOriginalText := CreateObject("Chilkat.StringBuilder")
nSuccess := oJwe2:DecryptSb(0, "utf-8", oSbOriginalText)
IF (nSuccess != 1)
    ? oJwe2:LastErrorText
    oSbPlainText:destroy()
    oJwe:destroy()
    oJweProtHdr:destroy()
    oSbJweCompressed:destroy()
    oSbJweUncompressed:destroy()
    oJwe2:destroy()
    oSbOriginalText:destroy()
    RETURN
ENDIF

? "original text from compressed JWE: "
? oSbOriginalText:GetAsString()

//  -----------------------------------------------------------
//  Do the same with the uncompressed JWE

nSuccess := oJwe2:LoadJweSb(oSbJweUncompressed)
IF (nSuccess != 1)
    ? oJwe2:LastErrorText
    oSbPlainText:destroy()
    oJwe:destroy()
    oJweProtHdr:destroy()
    oSbJweCompressed:destroy()
    oSbJweUncompressed:destroy()
    oJwe2:destroy()
    oSbOriginalText:destroy()
    RETURN
ENDIF

//  Set the AES wrap key.
oJwe2:SetWrappingKey(0, cAesWrappingKey, "base64url")

//  Decrypt.
oSbOriginalText:Clear()
nSuccess := oJwe2:DecryptSb(0, "utf-8", oSbOriginalText)
IF (nSuccess != 1)
    ? oJwe2:LastErrorText
    oSbPlainText:destroy()
    oJwe:destroy()
    oJweProtHdr:destroy()
    oSbJweCompressed:destroy()
    oSbJweUncompressed:destroy()
    oJwe2:destroy()
    oSbOriginalText:destroy()
    RETURN
ENDIF

? "original text from uncompressed JWE: "
? oSbOriginalText:GetAsString()

//  ------------------------------------------------
//  The output of this example is:
//  (Note: Your output data will be different because the content encryption key is randomly generated.)

//  eyJhbGciOiJBMTI4S1ciLCJlbmMiOiJBMTI4Q0JDLUhTMjU2IiwiemlwIjoiREVGIn0.xuW-pEAIdEUFnk10m8ocursvktO8Of9ByCCAt6LgKkkOtCWCUn1kQw.zpGj-9WVni3cQxyOuZbcGA.0hzP1myua3oYpUHwCIY_3edBUREbUpLaX6wYuJduOdI.Ppc6aEO3y3B8BJ1FKMPjlA
//  size of compressed JWE: 212
//  eyJhbGciOiJBMTI4S1ciLCJlbmMiOiJBMTI4Q0JDLUhTMjU2In0.N4KeyC7nnSFkieJOyE24_zKeuV_m7v5UKoJb1TgV4Yc_r2RzUPNvyA.6AEdyXSCKx-iMmUJyypSLg.QpixfyrwhGpmwUDp623viik4smPav7vwPLiC2r-V-jwnSfEH3mxWu6DbrIz3mixaqATwynmEBzVPxvS9jTXpSAGCnniib4_0WoPl3r_wF5tlsKOEe--jpNso-DKd1Tp8jJxj3JkFWt3IRnUUKGj17g.sBfDwFc5fzpaI-UW8-SW4g
//  size of uncompressed JWE: 303
//  original text from compressed JWE: 
//  Live long and prosper.
//  Live long and prosper.
//  Live long and prosper.
//  Live long and prosper.
//  
//  original text from uncompressed JWE: 
//  Live long and prosper.
//  Live long and prosper.
//  Live long and prosper.
//  Live long and prosper.
//

oSbPlainText:destroy()
oJwe:destroy()
oJweProtHdr:destroy()
oSbJweCompressed:destroy()
oSbJweUncompressed:destroy()
oJwe2:destroy()
oSbOriginalText:destroy()