Sample code for 30+ languages & platforms
Lua Requires Chilkat v9.5.0.66+

Compute JWK Thumbprint for RSA and EC Private Keys

See more ECC Examples

Demonstrates how to compute a JSON Web Key thumbprint for a private key (RSA or ECC).

Chilkat Lua Downloads

Download Chilkat for Lua
Lua 
local chilkat = require("chilkat")

local privKey = chilkat.PrivateKey.new()

-- A private key can be loaded from any format (binary DER, PEM, etc.)
-- This example will load the private keys from PEM format,
-- and will then compute the JWK thumbprint.

-- First do it for this RSA private key...

local sbPem = chilkat.StringBuilder.new()
local bCrlf = true
sbPem:append_line("-----BEGIN RSA PRIVATE KEY-----", bCrlf)
sbPem:append_line("Proc-Type: 4,ENCRYPTED", bCrlf)
sbPem:append_line("DEK-Info: DES-EDE3-CBC,2E65118E6C7B5207", bCrlf)
sbPem:append_line("", bCrlf)
sbPem:append_line("7cYUTW4ZBdmVZ4ILB08hcTdm5ib0E0zcy+I7pHpNQfJHtI7BJ4omys5S19ufJPBJ", bCrlf)
sbPem:append_line("IzYjeO7oTVqI37F6EUmjZqG4WVE2UQbQDkosZbZN82O4Ipu1lFAPEbwjqePMKufz", bCrlf)
sbPem:append_line("snSQHKfnbyyDPEVNlJbs19NXC8v6g+pQay5rH/I6N2iBxgsTmuemZ54EhNQMZyEN", bCrlf)
sbPem:append_line("R/CiheArWEH9H8/4hd2gc9Tb2s0MwGHILL4kbbNm5tp3xw4ik7OYWNrj3m+nG6Xb", bCrlf)
sbPem:append_line("vKXh2xEanAZAyMXTqDJTHdn7/CEqusQPJjZGV+Mf1kjKu7p4qcXFnIXP5ILnTW7b", bCrlf)
sbPem:append_line("lHoWC4eweDzKOMRzXmbABEVSUvx2SmPl4TcoC5L1SCAHEmZaKbaY7S5l53u6gl0f", bCrlf)
sbPem:append_line("ULuQbt7Hr3THznlNFKkGT1/yVNt2QOm1emZd55LaNe8E7XsNSlhl0grYQ+Ue8Jba", bCrlf)
sbPem:append_line("x85OapltVjxM9wVCwbgFyi04ihdKHo9e+uYKeTGKv0hU5O7HEH1ev6t/s2u/UG6h", bCrlf)
sbPem:append_line("TqEsYrVp0CMHpt5uAF6nZyK6GZ/CHTxh/rz1hADMofem59+e6tVtjnPGA3EjnJT8", bCrlf)
sbPem:append_line("BMOw/D2QIDxjxj2GUzz+YJp50ENhWrL9oSDkG2nzv4NVL77QIy+T/2/f4PgokUDO", bCrlf)
sbPem:append_line("QJjIfxPWE40cHGHpnQtZvEPoxP0H3T0YhmEVwuJxX3uaWOY/8Fa1c7Ln0SwWdfV5", bCrlf)
sbPem:append_line("gYvJV8o6c3sumcq1O3agPDlHC5O4IxG7AZQ8CHRDyASogzfkY6P579ZOGYaO4al7", bCrlf)
sbPem:append_line("WA1YIpsHs3/1f4SByMuWe0NVkFfvXckjpqGrBQpTmqQzk6baa0VQ0cwU3XlkwHac", bCrlf)
sbPem:append_line("WB/fQ4jylwFzZDcp5JAo53n6aU72zgNvDlGTNKwdXXZI5U3JPocH0AiZgFFWYJLd", bCrlf)
sbPem:append_line("63PJLDnjyE3i6XMVlxifXKkXVv0RYSz+ByS7Oz9aCgnQhNU8ycv+UxtfkPQih5zE", bCrlf)
sbPem:append_line("/0Y2EEFknajmFJpNXczzF8OEzaswmR0AOjcCiklZKRf61rf5faJxJhhqKEEBJuL6", bCrlf)
sbPem:append_line("oodDVRk3OGU1yQSBazT8nK3V+e6FMo3tWkra2BXFCD+pKxTy014Cp59S1w6F1Fjt", bCrlf)
sbPem:append_line("WX7eMWSLWfQ56j2kLMBHq5gb2arqlqH3fsYOTD3TNjCYF3Sgx309kVPuOK5vw61P", bCrlf)
sbPem:append_line("pnL/LN3iGY42WR+9lfAyNN2qj9zvwKwscyYs5+DPQoPmcPcVGc3v/u66bLcOGbEU", bCrlf)
sbPem:append_line("OlGa/6gdD4GCp5E4fP/7GbnEY/PW2abquFhGB+pVdl3/4+1U/8kItlfWNZoG4FhE", bCrlf)
sbPem:append_line("gjMd7glmrdFiNJFFpf5ks1lVXGqJ4mZxqtEZrxUEwciZjm4V27a+E2KyV9NnksZ6", bCrlf)
sbPem:append_line("xF4tGPKIPsvNTV5o8ZqjiacxgbYmr2ywqDXKCgpU/RWSh1sLapqSQqbH/w0MquUj", bCrlf)
sbPem:append_line("VhVX0RMYH/foKtjagZf/KO1/mnCITl86treIdachGgR4wr/qqMjrpPUaPLCRY3JQ", bCrlf)
sbPem:append_line("00XUP1Mu6YPE0SnMYAVxZheqKHly3a1pg4Xp7YWlM671oUORs3+VENfnbIxgr+2D", bCrlf)
sbPem:append_line("TiJT9PxwpfK53Oh7RBSWHJZRuAdLUXE8DG+bl0N/QkJM6pFUxTI1AQ==", bCrlf)
sbPem:append_line("-----END RSA PRIVATE KEY-----", bCrlf)

-- The actual password for the above PEM is "passwd".
local success = privKey:load_encrypted_pem(sbPem:get_as_string(), "passwd")
if not success then
    print(privKey.last_error_text)
    return
end

-- Generate the JWK thumbprint:
print("JWK thumbprint: " .. privKey:get_jwk_thumbprint("SHA256"))

-- Output:
-- JWK thumbprint: QzUpUAW1Y5iksGxq3r1o3JMROR6D7FLwvRlHmDQVg0I

-- --------------------------------------------------------------
-- Now let's do an EC private key.  The following is an unencrypted PEM containing a 384-bit EC key..
sbPem:clear()
sbPem:append_line("-----BEGIN PRIVATE KEY-----", bCrlf)
sbPem:append_line("MIG2AgEAMBAGByqGSM49AgEGBSuBBAAiBIGeMIGbAgEBBDAamStb0Xep3y3sWw2u", bCrlf)
sbPem:append_line("SSAdUPkgQ9Rvhlnx8XEVOYy2teh69T0on77ja02m03n8t8WhZANiAARUNSar38Rz", bCrlf)
sbPem:append_line("lKPyZFsNSGUanzpNRth0C+MikVEH8FAlDHMMpAs34dyF4IK0uxgbiEe9bQ+ieLrl", bCrlf)
sbPem:append_line("6xwFR0yaTivuwoyXC+ScGUnwnpaXmid6UUgw4ypbneHsaKuZ9JLdMAo=", bCrlf)
sbPem:append_line("-----END PRIVATE KEY-----", bCrlf)

success = privKey:load_pem(sbPem:get_as_string())
if not success then
    print(privKey.last_error_text)
    return
end

-- Generate the JWK thumbprint:
print("JWK thumbprint: " .. privKey:get_jwk_thumbprint("SHA256"))

-- Output:
-- JWK thumbprint: ABAUUfNSONFsZYvZ_o_0bsPT3qeG3jttXB09VC_ETWQ