--- a/spec/inputs/test_keys.lua	Thu Sep 29 23:15:39 2022 +0100
+++ b/spec/inputs/test_keys.lua	Thu Sep 29 23:17:42 2022 +0100
@@ -31,6 +31,49 @@
 -----END PUBLIC KEY-----
 ]];
 
+	-- JWT reference keys for ES512
+
+	ecdsa_521_public_pem = [[
+-----BEGIN PUBLIC KEY-----
+MIGbMBAGByqGSM49AgEGBSuBBAAjA4GGAAQBgc4HZz+/fBbC7lmEww0AO3NK9wVZ
+PDZ0VEnsaUFLEYpTzb90nITtJUcPUbvOsdZIZ1Q8fnbquAYgxXL5UgHMoywAib47
+6MkyyYgPk0BXZq3mq4zImTRNuaU9slj9TVJ3ScT3L1bXwVuPJDzpr5GOFpaj+WwM
+Al8G7CqwoJOsW7Kddns=
+-----END PUBLIC KEY-----
+]];
+
+	ecdsa_521_private_pem = [[
+-----BEGIN PRIVATE KEY-----
+MIHuAgEAMBAGByqGSM49AgEGBSuBBAAjBIHWMIHTAgEBBEIBiyAa7aRHFDCh2qga
+9sTUGINE5jHAFnmM8xWeT/uni5I4tNqhV5Xx0pDrmCV9mbroFtfEa0XVfKuMAxxf
+Z6LM/yKhgYkDgYYABAGBzgdnP798FsLuWYTDDQA7c0r3BVk8NnRUSexpQUsRilPN
+v3SchO0lRw9Ru86x1khnVDx+duq4BiDFcvlSAcyjLACJvjvoyTLJiA+TQFdmrear
+jMiZNE25pT2yWP1NUndJxPcvVtfBW48kPOmvkY4WlqP5bAwCXwbsKrCgk6xbsp12
+ew==
+-----END PRIVATE KEY-----
+]];
+
+	-- Self-generated keys for ES512
+
+	alt_ecdsa_521_public_pem = [[
+-----BEGIN PUBLIC KEY-----
+MIGbMBAGByqGSM49AgEGBSuBBAAjA4GGAAQBIxV0ecG/+qFc/kVPKs8Z6tjJEuRe
+dzrEaqABY6THu7BhCjEoxPr6iRYdiFPzNruFORsCAKf/NFLSoCqyrw9S0YMA1xc+
+uW01145oxT7Sp8BOH1MyOh7xNh+LFLi6X4lV6j5GQrM1sKSa3O5m0+VJmLy5b7cy
+oxNCzXrnEByz+EO2nYI=
+-----END PUBLIC KEY-----
+]];
+
+	alt_ecdsa_521_private_pem = [[
+-----BEGIN EC PRIVATE KEY-----
+MIHcAgEBBEIAV2XJQ4/5Pa5m43/AJdL4XzrRV/l7eQ1JObqmI95YDs3zxM5Mfygz
+DivhvuPdZCZUR+TdZQEdYN4LpllCzrDwmTCgBwYFK4EEACOhgYkDgYYABAEjFXR5
+wb/6oVz+RU8qzxnq2MkS5F53OsRqoAFjpMe7sGEKMSjE+vqJFh2IU/M2u4U5GwIA
+p/80UtKgKrKvD1LRgwDXFz65bTXXjmjFPtKnwE4fUzI6HvE2H4sUuLpfiVXqPkZC
+szWwpJrc7mbT5UmYvLlvtzKjE0LNeucQHLP4Q7adgg==
+-----END EC PRIVATE KEY-----
+]];
+
 	-- Self-generated EdDSA (Ed25519) keypair
 	eddsa_private_pem = [[
 -----BEGIN PRIVATE KEY-----

--- a/spec/util_jwt_spec.lua	Thu Sep 29 23:15:39 2022 +0100
+++ b/spec/util_jwt_spec.lua	Thu Sep 29 23:17:42 2022 +0100
@@ -89,6 +89,23 @@
 			};
 		};
 		{
+			algorithm = "ES512";
+			keys = {
+				{ test_keys.ecdsa_521_private_pem, test_keys.ecdsa_521_public_pem };
+				{ test_keys.alt_ecdsa_521_private_pem, test_keys.alt_ecdsa_521_public_pem };
+			};
+			{
+				name = "jwt.io reference";
+				[[eyJhbGciOiJFUzUxMiIsInR5cCI6IkpXVCJ9.eyJzdWIiOiIxMjM0NTY3ODkwIiwibmFtZSI6IkpvaG4gRG9lIiwiYWRtaW4iOnRydWUsImlhdCI6MTUxNjIzOTAyMn0.AbVUinMiT3J_03je8WTOIl-VdggzvoFgnOsdouAs-DLOtQzau9valrq-S6pETyi9Q18HH-EuwX49Q7m3KC0GuNBJAc9Tksulgsdq8GqwIqZqDKmG7hNmDzaQG1Dpdezn2qzv-otf3ZZe-qNOXUMRImGekfQFIuH_MjD2e8RZyww6lbZk]];
+				{     -- payload
+					sub = "1234567890";
+					name = "John Doe";
+					admin = true;
+					iat = 1516239022;
+				};
+			};
+		};
+		{
 			algorithm = "RS256";
 			keys = {
 				{ test_keys.rsa_private_pem, test_keys.rsa_public_pem };
@@ -197,10 +214,12 @@
 		untested_algorithms:remove(algorithm);
 
 		describe(algorithm, function ()
-			it("can do basic sign and verify", function ()
-				for _, keypair in ipairs(keypairs) do
+			describe("can do basic sign and verify", function ()
+				for keypair_n, keypair in ipairs(keypairs) do
 					local signing_key, verifying_key = keypair[1], keypair[2];
-					do_sign_verify_test(algorithm, signing_key, verifying_key, true);
+					it(("(test key pair %d)"):format(keypair_n), function ()
+						do_sign_verify_test(algorithm, signing_key, verifying_key, true);
+					end);
 				end
 			end);
 

--- a/util/jwt.lua	Thu Sep 29 23:15:39 2022 +0100
+++ b/util/jwt.lua	Thu Sep 29 23:17:42 2022 +0100
@@ -150,6 +150,7 @@
 local algorithms = {
 	HS256 = new_hmac_algorithm("HS256"), HS384 = new_hmac_algorithm("HS384"), HS512 = new_hmac_algorithm("HS512");
 	ES256 = new_ecdsa_algorithm("ES256", crypto.ecdsa_sha256_sign, crypto.ecdsa_sha256_verify, 32);
+	ES512 = new_ecdsa_algorithm("ES512", crypto.ecdsa_sha512_sign, crypto.ecdsa_sha512_verify, 66);
 	RS256 = new_rsa_algorithm("RS256"), RS384 = new_rsa_algorithm("RS384"), RS512 = new_rsa_algorithm("RS512");
 	PS256 = new_rsa_algorithm("PS256"), PS384 = new_rsa_algorithm("PS384"), PS512 = new_rsa_algorithm("PS512");
 };