diff --git a/node-api/src/main/kotlin/net/corda/nodeapi/internal/crypto/X509Utilities.kt b/node-api/src/main/kotlin/net/corda/nodeapi/internal/crypto/X509Utilities.kt
index 0908e5322b..33036f95ff 100644
--- a/node-api/src/main/kotlin/net/corda/nodeapi/internal/crypto/X509Utilities.kt
+++ b/node-api/src/main/kotlin/net/corda/nodeapi/internal/crypto/X509Utilities.kt
@@ -23,6 +23,7 @@ import org.bouncycastle.asn1.DERSequence
 import org.bouncycastle.asn1.DERUTF8String
 import org.bouncycastle.asn1.x500.X500Name
 import org.bouncycastle.asn1.x500.style.BCStyle
+import org.bouncycastle.asn1.x509.AuthorityKeyIdentifier
 import org.bouncycastle.asn1.x509.BasicConstraints
 import org.bouncycastle.asn1.x509.CRLDistPoint
 import org.bouncycastle.asn1.x509.DistributionPoint
@@ -33,6 +34,7 @@ import org.bouncycastle.asn1.x509.GeneralNames
 import org.bouncycastle.asn1.x509.KeyPurposeId
 import org.bouncycastle.asn1.x509.KeyUsage
 import org.bouncycastle.asn1.x509.NameConstraints
+import org.bouncycastle.asn1.x509.SubjectKeyIdentifier
 import org.bouncycastle.asn1.x509.SubjectPublicKeyInfo
 import org.bouncycastle.cert.X509CertificateHolder
 import org.bouncycastle.cert.X509v3CertificateBuilder