Lua 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. Lua

local chilkat = require("chilkat")

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

local crypt = chilkat.Crypt2.new()
local zip = chilkat.Zip.new()

local success = zip:open_zip("qa_data/pkpass/invalid.pkpass")
if not success then
    print(zip.last_error_text)
    return
end

-- 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"
-- }

local ent = chilkat.ZipEntry.new()
success = zip:entry_of("manifest.json", ent)
if not success then
    print(zip.last_error_text)
    return
end

-- Get the exact content of the manifest.json for later signature verification.
local bdManifest = chilkat.BinData.new()
success = ent:unzip_to_bd(bdManifest)

local json = chilkat.JsonObject.new()
json.emit_compact = false
json:load(ent:unzip_to_string(0, "utf-8"))
print(json:emit())

-- For each file in the JSON, get the filename and hex hash value.
crypt.encoding_mode = "hexlower"
crypt.hash_algorithm = "sha1"

local someHashesFailed = false
local filename = ""
local sbHashHex = chilkat.StringBuilder.new()
local bdFileData = chilkat.BinData.new()
local numMembers = json.size
local i = 0
while i < numMembers do
    filename = json:name_at(i)
    sbHashHex:clear()
    sbHashHex:append(json:string_at(i))

    success = zip:entry_of(filename, ent)
    if not success then
        print(zip.last_error_text)
        return
    end

    -- Get the data for this file.
    bdFileData:clear()
    success = ent:unzip_to_bd(bdFileData)

    local computedHashHex = crypt:hash_bd_enc(bdFileData)
    if not sbHashHex:contents_equal(computedHashHex, false) then
        print("Computed hash does not match stored hash for " .. filename)
        print("  computed: " .. computedHashHex)
        print("  stored:   " .. sbHashHex:get_as_string())
        someHashesFailed = true
    else
        print("hash verified for " .. filename .. "(" .. computedHashHex .. ")")
    end

    i = i + 1
end

if someHashesFailed then
    print("Some hashes failed.")
    return
end

-- Let's verify the signature..
-- First get the signature.
success = zip:entry_of("signature", ent)
if not success then
    print(zip.last_error_text)
    return
end

local bdSignature = chilkat.BinData.new()
success = ent:unzip_to_bd(bdSignature)

-- Show the contents of the signature in base64 encoding.
print("Signature:")
print(bdSignature:get_encoded("base64_mime"))
print("----")

-- Verify the signature against the manifest.json
crypt.encoding_mode = "base64"
local verified = crypt:verify_bd_enc(bdManifest, bdSignature:get_encoded("base64"))
if not verified then
    print(crypt.last_error_text)
end

print("signature verified = " .. tostring(verified))