Xbase++
Compute JWK Thumbprint for RSA and EC Private Keys

Demonstrates how to compute a JSON Web Key thumbprint for a private key (RSA or ECC).
Note: This example requires Chilkat v9.5.0.66 or greater.
Chilkat Xbase++ Downloads

Xbase++
LOCAL nSuccess
LOCAL oPrivKey
LOCAL oSbPem
LOCAL nBCrlf

nSuccess := 0

oPrivKey := CreateObject("Chilkat.PrivateKey")

//  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...

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

//  The actual password for the above PEM is "passwd".
nSuccess := oPrivKey:LoadEncryptedPem(oSbPem:GetAsString(), "passwd")
IF (nSuccess != 1)
    ? oPrivKey:LastErrorText
    oPrivKey:destroy()
    oSbPem:destroy()
    RETURN
ENDIF

//  Generate the JWK thumbprint:
? "JWK thumbprint: " + oPrivKey:GetJwkThumbprint("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..
oSbPem:Clear()
oSbPem:AppendLine("-----BEGIN PRIVATE KEY-----", nBCrlf)
oSbPem:AppendLine("MIG2AgEAMBAGByqGSM49AgEGBSuBBAAiBIGeMIGbAgEBBDAamStb0Xep3y3sWw2u", nBCrlf)
oSbPem:AppendLine("SSAdUPkgQ9Rvhlnx8XEVOYy2teh69T0on77ja02m03n8t8WhZANiAARUNSar38Rz", nBCrlf)
oSbPem:AppendLine("lKPyZFsNSGUanzpNRth0C+MikVEH8FAlDHMMpAs34dyF4IK0uxgbiEe9bQ+ieLrl", nBCrlf)
oSbPem:AppendLine("6xwFR0yaTivuwoyXC+ScGUnwnpaXmid6UUgw4ypbneHsaKuZ9JLdMAo=", nBCrlf)
oSbPem:AppendLine("-----END PRIVATE KEY-----", nBCrlf)

nSuccess := oPrivKey:LoadPem(oSbPem:GetAsString())
IF (nSuccess != 1)
    ? oPrivKey:LastErrorText
    oPrivKey:destroy()
    oSbPem:destroy()
    RETURN
ENDIF

//  Generate the JWK thumbprint:
? "JWK thumbprint: " + oPrivKey:GetJwkThumbprint("SHA256")

//  Output:
//  JWK thumbprint: ABAUUfNSONFsZYvZ_o_0bsPT3qeG3jttXB09VC_ETWQ

oPrivKey:destroy()
oSbPem:destroy()