diff --git a/Sources/ShieldX509/ExtensionAuthorityKeyIdentifier.swift b/Sources/ShieldX509/ExtensionAuthorityKeyIdentifier.swift
index 3c0808afc..3d7173934 100644
--- a/Sources/ShieldX509/ExtensionAuthorityKeyIdentifier.swift
+++ b/Sources/ShieldX509/ExtensionAuthorityKeyIdentifier.swift
@@ -27,6 +27,7 @@ public struct AuthorityKeyIdentifier: Equatable, Hashable, Codable, NonCriticalE
     authorityCertIssuer: GeneralNames? = nil,
     authorityCertSerialNumber: TBSCertificate.SerialNumber? = nil
   ) {
+    precondition(authorityCertSerialNumber?.sign != .minus)
     self.keyIdentifier = keyIdentifier
     self.authorityCertIssuer = authorityCertIssuer
     self.authorityCertSerialNumber = authorityCertSerialNumber
diff --git a/Tests/CertificateBuilderECTests.swift b/Tests/CertificateBuilderECTests.swift
index b5b00eb43..18b67963a 100644
--- a/Tests/CertificateBuilderECTests.swift
+++ b/Tests/CertificateBuilderECTests.swift
@@ -186,7 +186,7 @@ class CertificateBuilderECTests: XCTestCase {
         .authorityKeyIdentifier(
           Digester.digest(Self.keyPair.encodedPublicKey(), using: .sha1),
           certIssuer: [.dnsName("github.com/outfoxx/Shield/CA")],
-          certSerialNumber: Integer(sign: .plus, magnitude: .randomInteger(withExactWidth: 19 * 8))
+          certSerialNumber: Certificate.Builder.randomSerialNumber()
         )
         .computeSubjectKeyIdentifier()
         .valid(for: 86400 * 365)
diff --git a/Tests/CertificateBuilderRSATests.swift b/Tests/CertificateBuilderRSATests.swift
index 367eeddb8..412224450 100644
--- a/Tests/CertificateBuilderRSATests.swift
+++ b/Tests/CertificateBuilderRSATests.swift
@@ -186,7 +186,7 @@ class CertificateBuilderRSATests: XCTestCase {
         .authorityKeyIdentifier(
           Digester.digest(Self.keyPair.encodedPublicKey(), using: .sha1),
           certIssuer: [.dnsName("github.com/outfoxx/Shield/CA")],
-          certSerialNumber: Integer(sign: .plus, magnitude: .randomInteger(withExactWidth: 19 * 8))
+          certSerialNumber: Certificate.Builder.randomSerialNumber()
         )
         .computeSubjectKeyIdentifier()
         .valid(for: 86400 * 365)