PowerBuilder

JWE using PBES2 Key Wrapping

See more JSON Web Encryption (JWE) Examples

Demonstrates how to create and decrypt a JWE that using PBES2 key wrapping.

This example demonstrates PBES2 with HMAC SHA-256 and A128KW wrapping. It is also possible to do the following by simply changing the "alg" parameter:

• PBES2 with HMAC SHA-384 and A192KW wrapping
• PBES2 with HMAC SHA-512 and A256KW wrapping

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

PowerBuilder

integer li_rc
integer li_Success
string ls_Plaintext
oleobject loo_Jwe
oleobject loo_JweProtHdr
oleobject loo_Prng
integer li_RecipientIndex
string ls_StrJwe
oleobject loo_Jwe2
string ls_OriginalPlaintext

li_Success = 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.

ls_Plaintext = "Live long and prosper."

loo_Jwe = create oleobject
li_rc = loo_Jwe.ConnectToNewObject("Chilkat.Jwe")
if li_rc < 0 then
    destroy loo_Jwe
    MessageBox("Error","Connecting to COM object failed")
    return
end if

// First build the JWE Protected Header..
loo_JweProtHdr = create oleobject
li_rc = loo_JweProtHdr.ConnectToNewObject("Chilkat.JsonObject")

loo_JweProtHdr.AppendString("alg","PBES2-HS256+A128KW")
loo_JweProtHdr.AppendString("enc","A128GCM")

// PBES2 requires two additional parameters:
// 1) A random salt parameter ("p2s") containing 8 or more bytes in base64url format.
// 2) An iteration count parameter ("p2c").  A minimum count of 1000 is recommended.
//    The iteration count is intended to make the PBES2 computation more expensive (time consuming)
//    to prevent brute-force attacks.
loo_Prng = create oleobject
li_rc = loo_Prng.ConnectToNewObject("Chilkat.Prng")

loo_JweProtHdr.AppendString("p2s",loo_Prng.GenRandom(16,"base64url"))
loo_JweProtHdr.AppendString("p2c","1000")

Write-Debug "JWE Protected Header: " + loo_JweProtHdr.Emit()
Write-Debug "--"

// Don't forget to actually provide the protected header to the JWE object:
loo_Jwe.SetProtectedHeader(loo_JweProtHdr)

// Set the PBES2 password
li_RecipientIndex = 0
loo_Jwe.SetPassword(li_RecipientIndex,"top secret")

// Encrypt and return the JWE:
ls_StrJwe = loo_Jwe.Encrypt(ls_Plaintext,"utf-8")
if loo_Jwe.LastMethodSuccess <> 1 then
    Write-Debug loo_Jwe.LastErrorText
    destroy loo_Jwe
    destroy loo_JweProtHdr
    destroy loo_Prng
    return
end if

// Show the JWE we just created:
Write-Debug ls_StrJwe

// Decrypt the JWE.
loo_Jwe2 = create oleobject
li_rc = loo_Jwe2.ConnectToNewObject("Chilkat.Jwe")

li_Success = loo_Jwe2.LoadJwe(ls_StrJwe)
if li_Success <> 1 then
    Write-Debug loo_Jwe2.LastErrorText
    destroy loo_Jwe
    destroy loo_JweProtHdr
    destroy loo_Prng
    destroy loo_Jwe2
    return
end if

// Set the PBES2 password
loo_Jwe2.SetPassword(li_RecipientIndex,"top secret")

// Decrypt.
ls_OriginalPlaintext = loo_Jwe2.Decrypt(0,"utf-8")
if loo_Jwe2.LastMethodSuccess <> 1 then
    Write-Debug loo_Jwe2.LastErrorText
    destroy loo_Jwe
    destroy loo_JweProtHdr
    destroy loo_Prng
    destroy loo_Jwe2
    return
end if

Write-Debug "original text: "
Write-Debug ls_OriginalPlaintext

// Sample output:

// JWE Protected Header: {"alg":"PBES2-HS256+A128KW","enc":"A128GCM","p2s":"z39rTEfRy1T1Yn_D1mZRlg","p2c":"1000"}
// --
// eyJhbGciOiJQQkVTMi1IUzI1NitBMTI4S1ciLCJlbmMiOiJBMTI4R0NNIiwicDJzIjoiejM5clRFZlJ5MVQxWW5fRDFtWlJsZyIsInAyYyI6IjEwMDAifQ.koYt6PrFmYwcwdcT7ZcvXHA1d-Xez5h4.luGlbvEnZp-7IsBOj42Yhw.YMTcfLf8Qe4zazozGV2OAu3cUdQ8Kg.rWub47ESWkc6IqZJTvSTmg
// original text: 
// Live long and prosper.


destroy loo_Jwe
destroy loo_JweProtHdr
destroy loo_Prng
destroy loo_Jwe2