diff --git a/Sources/X509/SignatureAlgorithm.swift b/Sources/X509/SignatureAlgorithm.swift
index 02833bff..603b82f3 100644
--- a/Sources/X509/SignatureAlgorithm.swift
+++ b/Sources/X509/SignatureAlgorithm.swift
@@ -177,7 +177,7 @@ extension Certificate.SignatureAlgorithm {
                 return 0x0807
             default:
                 throw CertificateError.unsupportedSignatureAlgorithm(
-                    reason: "SignatureAlgorithm(\(self)) has an unsupprted value"
+                    reason: "SignatureAlgorithm(\(self)) has an unsupported value"
                 )
             }
         }