(Objective-C) 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.

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#import <CkoPrivateKey.h>
#import <CkoStringBuilder.h>

CkoPrivateKey *privKey = [[CkoPrivateKey alloc] init];

// 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...

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

// The actual password for the above PEM is "passwd".
BOOL success = [privKey LoadEncryptedPem: [sbPem GetAsString] password: @"passwd"];
if (success != YES) {
    NSLog(@"%@",privKey.LastErrorText);
    return;
}

// Generate the JWK thumbprint:
NSLog(@"%@%@",@"JWK thumbprint: ",[privKey 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..
[sbPem Clear];
[sbPem AppendLine: @"-----BEGIN PRIVATE KEY-----" crlf: bCrlf];
[sbPem AppendLine: @"MIG2AgEAMBAGByqGSM49AgEGBSuBBAAiBIGeMIGbAgEBBDAamStb0Xep3y3sWw2u" crlf: bCrlf];
[sbPem AppendLine: @"SSAdUPkgQ9Rvhlnx8XEVOYy2teh69T0on77ja02m03n8t8WhZANiAARUNSar38Rz" crlf: bCrlf];
[sbPem AppendLine: @"lKPyZFsNSGUanzpNRth0C+MikVEH8FAlDHMMpAs34dyF4IK0uxgbiEe9bQ+ieLrl" crlf: bCrlf];
[sbPem AppendLine: @"6xwFR0yaTivuwoyXC+ScGUnwnpaXmid6UUgw4ypbneHsaKuZ9JLdMAo=" crlf: bCrlf];
[sbPem AppendLine: @"-----END PRIVATE KEY-----" crlf: bCrlf];

success = [privKey LoadPem: [sbPem GetAsString]];
if (success != YES) {
    NSLog(@"%@",privKey.LastErrorText);
    return;
}

// Generate the JWK thumbprint:
NSLog(@"%@%@",@"JWK thumbprint: ",[privKey GetJwkThumbprint: @"SHA256"]);

// Output:
// JWK thumbprint: ABAUUfNSONFsZYvZ_o_0bsPT3qeG3jttXB09VC_ETWQ