B4X Requires Chilkat v11.0.0+

Validate a .pkpass Archive

See more Digital Signatures Examples

Opens a .pkpass archive (which is just a .zip renamed to .pkpass) and validates the contents. The hashes in the manifest are compared with the computed hash values for each individual file. If all computed hash values match, then the signature is verified. B4X

Dim success As Boolean = False

'  This example assumes the Chilkat API to have been previously unlocked.
'  See Global Unlock Sample for sample code.

Dim crypt As ChilkatCrypt2
crypt.Initialize("crypt")
Dim zip As ChilkatZip
zip.Initialize("zip")

success = zip.OpenZip("qa_data/pkpass/invalid.pkpass")
If success = False Then
    Log(zip.LastErrorText)
    Return
End If


'  Get the contents of the manifest.json file, which contains something like this:

'  {
'    "icon.png" : "0296b01347b3173e98438a003b0e88986340b2d8",
'    "logo.png" : "25de09e2d3b01ce1fe00c2ca9a90a2be1aaa05cf",
'    "icon@2x.png" : "5afd9585b08c65fdf105a90c8bd643407cba2787",
'    "pass.json" : "145ea5a5db784fff485126c77ecf7a1fc2a88ee7",
'    "strip@2x.png" : "468fa7bc93e6b55342b56fda09bdce7c829d7d46",
'    "strip.png" : "736d01f84cb73d06e8a9932e43076d68f19461ff"
'  }

Dim ent As ChilkatZipEntry
ent.Initialize("ent")
success = zip.EntryOf("manifest.json", ent)
If success = False Then
    Log(zip.LastErrorText)
    Return
End If


'  Get the exact content of the manifest.json for later signature verification.
Dim bdManifest As ChilkatBinData
bdManifest.Initialize
success = ent.UnzipToBd(bdManifest)

Dim json As ChilkatJsonObject
json.Initialize
json.EmitCompact = False
json.Load(ent.UnzipToString(0, "utf-8"))
Log(json.Emit)

'  For each file in the JSON, get the filename and hex hash value.
crypt.EncodingMode = "hexlower"
crypt.HashAlgorithm = "sha1"

Dim someHashesFailed As Boolean = False
Dim filename As String
Dim sbHashHex As ChilkatStringBuilder
sbHashHex.Initialize
Dim bdFileData As ChilkatBinData
bdFileData.Initialize
Dim numMembers As Int = json.Size
Dim i As Int = 0
Do While i < numMembers
    filename = json.NameAt(i)
    sbHashHex.Clear
    sbHashHex.Append(json.StringAt(i))

    success = zip.EntryOf(filename, ent)
    If success = False Then
        Log(zip.LastErrorText)
        Return
    End If


    '  Get the data for this file.
    bdFileData.Clear
    success = ent.UnzipToBd(bdFileData)

    Dim computedHashHex As String = crypt.HashBdENC(bdFileData)
    If sbHashHex.ContentsEqual(computedHashHex, False) = False Then
        Log("Computed hash does not match stored hash for " & filename)
        Log("  computed: " & computedHashHex)
        Log("  stored:   " & sbHashHex.GetAsString)
        someHashesFailed = True
    Else
        Log("hash verified for " & filename & "(" & computedHashHex & ")")
    End If


    i = i + 1
Loop

If someHashesFailed = True Then
    Log("Some hashes failed.")
    Return
End If


'  Let's verify the signature..
'  First get the signature.
success = zip.EntryOf("signature", ent)
If success = False Then
    Log(zip.LastErrorText)
    Return
End If


Dim bdSignature As ChilkatBinData
bdSignature.Initialize
success = ent.UnzipToBd(bdSignature)

'  Show the contents of the signature in base64 encoding.
Log("Signature:")
Log(bdSignature.GetEncoded("base64_mime"))
Log("----")

'  Verify the signature against the manifest.json
crypt.EncodingMode = "base64"
Dim verified As Boolean = crypt.VerifyBdENC(bdManifest, bdSignature.GetEncoded("base64"))
If verified = False Then
    Log(crypt.LastErrorText)
End If

Log("signature verified = " & verified)