(PowerBuilder) JWE Using Flattened JWE JSON Serialization

This example duplicates the example A.5 in RFC 7516 for JSON Web Encryption (JWE).

This example demonstrates using the flattened JWE JSON Serialization syntax. This example demonstrates the capability for encrypting the plaintext to a single recipient in a flattened JSON structure.

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

Chilkat ActiveX Downloads ActiveX for 32-bit and 64-bit Windows

integer li_rc
integer li_Success
string ls_Plaintext
oleobject loo_Jwe
oleobject loo_JweProtHdr
oleobject loo_JweRecipientHdr
integer li_RecipientIndex
oleobject loo_JweUnprotHdr
string ls_AesWrappingKey
string ls_StrJwe
oleobject loo_JsonTemp
oleobject loo_Jwe2
string ls_OriginalPlaintext
oleobject loo_SbJwe

// 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
// Use "Chilkat_9_5_0.Jwe" for versions of Chilkat < 10.0.0
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: {"enc":"A128CBC-HS256"}
loo_JweProtHdr = create oleobject
// Use "Chilkat_9_5_0.JsonObject" for versions of Chilkat < 10.0.0
li_rc = loo_JweProtHdr.ConnectToNewObject("Chilkat.JsonObject")

loo_JweProtHdr.AppendString("enc","A128CBC-HS256")
loo_Jwe.SetProtectedHeader(loo_JweProtHdr)

// We have a single recipient that uses AES Key Wrap to encrypt the CEK.
// 
//      {"alg":"A128KW","kid":"7"}

loo_JweRecipientHdr = create oleobject
// Use "Chilkat_9_5_0.JsonObject" for versions of Chilkat < 10.0.0
li_rc = loo_JweRecipientHdr.ConnectToNewObject("Chilkat.JsonObject")

loo_JweRecipientHdr.AppendString("alg","A128KW")
loo_JweRecipientHdr.AppendString("kid","7")
li_RecipientIndex = 0
loo_Jwe.SetRecipientHeader(li_RecipientIndex,loo_JweRecipientHdr)

// Set the Shared Unprotected Header:  {"jku":"https://server.example.com/keys.jwks"}
loo_JweUnprotHdr = create oleobject
// Use "Chilkat_9_5_0.JsonObject" for versions of Chilkat < 10.0.0
li_rc = loo_JweUnprotHdr.ConnectToNewObject("Chilkat.JsonObject")

loo_JweUnprotHdr.AppendString("jku","https://server.example.com/keys.jwks")
loo_Jwe.SetUnprotectedHeader(loo_JweUnprotHdr)

// Set the AES key wrapping key.
ls_AesWrappingKey = "GawgguFyGrWKav7AX4VKUg"
li_RecipientIndex = 0
loo_Jwe.SetWrappingKey(li_RecipientIndex,ls_AesWrappingKey,"base64url")

// OK.. everything has been specified.
// Now encrypt.  
// Indicate that we prefer the flattened JSON serialization.
loo_Jwe.PreferFlattened = 1
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_JweRecipientHdr
    destroy loo_JweUnprotHdr
    return
end if

// The JWE is produced in the most compact form possible (a single line).
// Let's load it into a JSON object and examine in a non-compact pretty-printed format:
loo_JsonTemp = create oleobject
// Use "Chilkat_9_5_0.JsonObject" for versions of Chilkat < 10.0.0
li_rc = loo_JsonTemp.ConnectToNewObject("Chilkat.JsonObject")

loo_JsonTemp.Load(ls_StrJwe)
loo_JsonTemp.EmitCompact = 0
Write-Debug loo_JsonTemp.Emit()

// The JWE looks like this:
// (Note: Because of random values used in the encryption process, your encrypted results will be different.)

// 	{ 
// 	  "protected": "eyJlbmMiOiJBMTI4Q0JDLUhTMjU2In0",
// 	  "unprotected": { 
// 	    "jku": "https://server.example.com/keys.jwks"
// 	  },
// 	  "header": { 
// 	    "alg": "A128KW",
// 	    "kid": "7"
// 	  },
// 	  "encrypted_key": "FW7z9VxOvnF2ClicvUT4HTeqcdyh90C6qytfEFJsOb77FOwTfYrc3w",
// 	  "iv": "O6Ly5-eML3zTs-_fNX3D5Q",
// 	  "ciphertext": "Q8NLmeac9JhLh0CQPuG_7D9wVDb55eToCh0g5-FQ4M0",
// 	  "tag": "slzlo6-J9C7wSDF4dh_kBg"
// 	} 

// Now decrypt......................................

// First, load the JWE..
loo_Jwe2 = create oleobject
// Use "Chilkat_9_5_0.Jwe" for versions of Chilkat < 10.0.0
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_JweRecipientHdr
    destroy loo_JweUnprotHdr
    destroy loo_JsonTemp
    destroy loo_Jwe2
    return
end if

// Set the AES wrap key..
li_RecipientIndex = 0
loo_Jwe2.SetWrappingKey(li_RecipientIndex,ls_AesWrappingKey,"base64url")

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

Write-Debug "original text decrypted with AES key wrap key: "
Write-Debug ls_OriginalPlaintext

// ---------------------------------------------------------------------------------
// It should also be possible to decrypt the flattened JWE as shown in RFC 7516, Appendix A.5
// because it was produced using the same key.

loo_SbJwe = create oleobject
// Use "Chilkat_9_5_0.StringBuilder" for versions of Chilkat < 10.0.0
li_rc = loo_SbJwe.ConnectToNewObject("Chilkat.StringBuilder")

loo_SbJwe.Append("{")
loo_SbJwe.Append("~"protected~":")
loo_SbJwe.Append("~"eyJlbmMiOiJBMTI4Q0JDLUhTMjU2In0~",")
loo_SbJwe.Append("~"unprotected~":")
loo_SbJwe.Append("{~"jku~":~"https://server.example.com/keys.jwks~"},")
loo_SbJwe.Append("~"header~":")
loo_SbJwe.Append("{~"alg~":~"A128KW~",~"kid~":~"7~"},")
loo_SbJwe.Append("~"encrypted_key~":")
loo_SbJwe.Append("~"6KB707dM9YTIgHtLvtgWQ8mKwboJW3of9locizkDTHzBC2IlrT1oOQ~",")
loo_SbJwe.Append("~"iv~":")
loo_SbJwe.Append("~"AxY8DCtDaGlsbGljb3RoZQ~",")
loo_SbJwe.Append("~"ciphertext~":")
loo_SbJwe.Append("~"KDlTtXchhZTGufMYmOYGS4HffxPSUrfmqCHXaI9wOGY~",")
loo_SbJwe.Append("~"tag~":")
loo_SbJwe.Append("~"Mz-VPPyU4RlcuYv1IwIvzw~"")
loo_SbJwe.Append("}")

li_Success = loo_Jwe2.LoadJweSb(loo_SbJwe)
if li_Success <> 1 then
    Write-Debug loo_Jwe2.LastErrorText
    destroy loo_Jwe
    destroy loo_JweProtHdr
    destroy loo_JweRecipientHdr
    destroy loo_JweUnprotHdr
    destroy loo_JsonTemp
    destroy loo_Jwe2
    destroy loo_SbJwe
    return
end if

li_RecipientIndex = 0
loo_Jwe2.SetWrappingKey(li_RecipientIndex,ls_AesWrappingKey,"base64url")

ls_OriginalPlaintext = loo_Jwe2.Decrypt(li_RecipientIndex,"utf-8")
if loo_Jwe2.LastMethodSuccess <> 1 then
    Write-Debug loo_Jwe2.LastErrorText
    destroy loo_Jwe
    destroy loo_JweProtHdr
    destroy loo_JweRecipientHdr
    destroy loo_JweUnprotHdr
    destroy loo_JsonTemp
    destroy loo_Jwe2
    destroy loo_SbJwe
    return
end if

Write-Debug "original text decrypted from published flattened JWE: "
Write-Debug ls_OriginalPlaintext

// The output:

// original text decrypted with AES key wrap key: 
// Live long and prosper.
// original text decrypted from published flattened JWE: 
// Live long and prosper.


destroy loo_Jwe
destroy loo_JweProtHdr
destroy loo_JweRecipientHdr
destroy loo_JweUnprotHdr
destroy loo_JsonTemp
destroy loo_Jwe2
destroy loo_SbJwe