diff --git a/src/main.zig b/src/main.zig
index d106b91..7cd0361 100644
--- a/src/main.zig
+++ b/src/main.zig
@@ -76,7 +76,7 @@ const Args = struct {
     config_location: []const u8,
 };
 
-const OtpAuthUrl = struct { name: []const u8, secretEncoded: []const u8, url: []const u8, period: u32, digits: u4 };
+const OtpAuthUrl = struct { name: []const u8, secretEncoded: []const u8, url: []const u8, period: u32, digits: u4, algorithm: []const u8 };
 
 const Authenticator = struct {
     url: OtpAuthUrl,
@@ -199,6 +199,7 @@ fn parseOtpAuthUrl(allocator: Allocator, url: []const u8) !OtpAuthUrl {
         .url = url,
         .period = if (params.get("period") != null) try std.fmt.parseInt(u32, params.get("period").?, 10) else 30,
         .digits = if (params.get("digits") != null) try std.fmt.parseInt(u4, params.get("digits").?, 10) else 6,
+        .algorithm = if (params.get("algorithm") != null) params.get("algorithm").? else "SHA1",
     };
 }
 
@@ -373,14 +374,14 @@ test "zero padding" {
 }
 
 test "authenticator generate code with 6 digits" {
-    const authenticator = Authenticator{ .url = OtpAuthUrl{ .name = "TestAuthenticator", .secretEncoded = "HJ5PX4IFQKD37HFNXLJYBAVD5G6NMMUOKUCDXJ4XTLUUBWSXRXEN5SR4MLAZA5M2", .url = "not needed", .period = 30, .digits = 6 } };
+    const authenticator = Authenticator{ .url = OtpAuthUrl{ .name = "TestAuthenticator", .secretEncoded = "HJ5PX4IFQKD37HFNXLJYBAVD5G6NMMUOKUCDXJ4XTLUUBWSXRXEN5SR4MLAZA5M2", .url = "not needed", .period = 30, .digits = 6, .algorithm = "SHA1" } };
 
     const code = try authenticator.code(std.testing.allocator, _closure_return_1725695340);
     defer std.testing.allocator.free(code);
     try std.testing.expectEqualStrings("218139", code);
 }
 test "authenticator generate code with 10 digits and zero padding" {
-    const authenticator = Authenticator{ .url = OtpAuthUrl{ .name = "TestAuthenticator", .secretEncoded = "HJ5PX4IFQKD37HFNXLJYBAVD5G6NMMUOKUCDXJ4XTLUUBWSXRXEN5SR4MLAZA5M2", .url = "not needed", .period = 60, .digits = 10 } };
+    const authenticator = Authenticator{ .url = OtpAuthUrl{ .name = "TestAuthenticator", .secretEncoded = "HJ5PX4IFQKD37HFNXLJYBAVD5G6NMMUOKUCDXJ4XTLUUBWSXRXEN5SR4MLAZA5M2", .url = "not needed", .period = 60, .digits = 10, .algorithm = "SHA1" } };
 
     const code = try authenticator.code(std.testing.allocator, _closure_return_1725695340);
     defer std.testing.allocator.free(code);
@@ -390,17 +391,17 @@ test "authenticator generate code with 10 digits and zero padding" {
 test "testcases from https://www.rfc-editor.org/rfc/rfc6238#appendix-A" {
     const secretForSha1 = "GEZDGNBVGY3TQOJQGEZDGNBVGY3TQOJQ"; // plain: "12345678901234567890"  hex: "3132333435363738393031323334353637383930"
 
-    try testTOTP(OtpAuthUrl{ .name = "", .secretEncoded = secretForSha1, .url = "", .period = 30, .digits = 8 }, _closure_return_59, "94287082");
+    try testTOTP(OtpAuthUrl{ .name = "", .secretEncoded = secretForSha1, .url = "", .period = 30, .digits = 8, .algorithm = "SHA1" }, _closure_return_59, "94287082");
 
-    try testTOTP(OtpAuthUrl{ .name = "", .secretEncoded = secretForSha1, .url = "", .period = 30, .digits = 8 }, _closure_return_1111111109, "07081804");
+    try testTOTP(OtpAuthUrl{ .name = "", .secretEncoded = secretForSha1, .url = "", .period = 30, .digits = 8, .algorithm = "SHA1" }, _closure_return_1111111109, "07081804");
 
-    try testTOTP(OtpAuthUrl{ .name = "", .secretEncoded = secretForSha1, .url = "", .period = 30, .digits = 8 }, _closure_return_1111111111, "14050471");
+    try testTOTP(OtpAuthUrl{ .name = "", .secretEncoded = secretForSha1, .url = "", .period = 30, .digits = 8, .algorithm = "SHA1" }, _closure_return_1111111111, "14050471");
 
-    try testTOTP(OtpAuthUrl{ .name = "", .secretEncoded = secretForSha1, .url = "", .period = 30, .digits = 8 }, _closure_return_1234567890, "89005924");
+    try testTOTP(OtpAuthUrl{ .name = "", .secretEncoded = secretForSha1, .url = "", .period = 30, .digits = 8, .algorithm = "SHA1" }, _closure_return_1234567890, "89005924");
 
-    try testTOTP(OtpAuthUrl{ .name = "", .secretEncoded = secretForSha1, .url = "", .period = 30, .digits = 8 }, _closure_return_2000000000, "69279037");
+    try testTOTP(OtpAuthUrl{ .name = "", .secretEncoded = secretForSha1, .url = "", .period = 30, .digits = 8, .algorithm = "SHA1" }, _closure_return_2000000000, "69279037");
 
-    try testTOTP(OtpAuthUrl{ .name = "", .secretEncoded = secretForSha1, .url = "", .period = 30, .digits = 8 }, _closure_return_20000000000, "65353130");
+    try testTOTP(OtpAuthUrl{ .name = "", .secretEncoded = secretForSha1, .url = "", .period = 30, .digits = 8, .algorithm = "SHA1" }, _closure_return_20000000000, "65353130");
 }
 
 fn testTOTP(otpAuthUrl: OtpAuthUrl, timeFunc: *const fn () i64, expected: []const u8) !void {
@@ -440,26 +441,26 @@ fn _closure_return_20000000000() i64 {
 }
 
 test "secret is not Base32 - invalid padding" {
-    const authenticator = Authenticator{ .url = OtpAuthUrl{ .name = "", .secretEncoded = "H", .url = "", .period = 60, .digits = 6 } };
+    const authenticator = Authenticator{ .url = OtpAuthUrl{ .name = "", .secretEncoded = "H", .url = "", .period = 60, .digits = 6, .algorithm = "SHA1" } };
 
     const actualError = authenticator.code(std.testing.allocator, _closure_return_1725695340);
     try std.testing.expectError(Base32Error.InvalidPadding, actualError);
 }
 test "secret is not Base32 - invalid padding, input has too many bytes" {
-    const authenticator = Authenticator{ .url = OtpAuthUrl{ .name = "", .secretEncoded = "HAX", .url = "", .period = 60, .digits = 6 } };
+    const authenticator = Authenticator{ .url = OtpAuthUrl{ .name = "", .secretEncoded = "HAX", .url = "", .period = 60, .digits = 6, .algorithm = "SHA1" } };
 
     const actualError = authenticator.code(std.testing.allocator, _closure_return_1725695340);
     try std.testing.expectError(Base32Error.InvalidPadding, actualError);
 }
 test "secret is not Base32 - invalid padding, trailing bits are not 0" {
-    const authenticator = Authenticator{ .url = OtpAuthUrl{ .name = "", .secretEncoded = "HX", .url = "", .period = 60, .digits = 6 } };
+    const authenticator = Authenticator{ .url = OtpAuthUrl{ .name = "", .secretEncoded = "HX", .url = "", .period = 60, .digits = 6, .algorithm = "SHA1" } };
 
     const actualError = authenticator.code(std.testing.allocator, _closure_return_1725695340);
     try std.testing.expectError(Base32Error.InvalidPadding, actualError);
 }
 
 test "secret is not Base32 - invalid character" {
-    const authenticator = Authenticator{ .url = OtpAuthUrl{ .name = "", .secretEncoded = "0", .url = "", .period = 60, .digits = 6 } };
+    const authenticator = Authenticator{ .url = OtpAuthUrl{ .name = "", .secretEncoded = "0", .url = "", .period = 60, .digits = 6, .algorithm = "SHA1" } };
 
     const actualError = authenticator.code(std.testing.allocator, _closure_return_1725695340);
     try std.testing.expectError(Base32Error.InvalidCharacter, actualError);