content: package local.org.bouncycastle.asn1.x509;
  
  import local.org.bouncycastle.asn1.ASN1Object;
  import local.org.bouncycastle.asn1.ASN1OctetString;
  import local.org.bouncycastle.asn1.ASN1Primitive;
  import local.org.bouncycastle.asn1.ASN1TaggedObject;
  import local.org.bouncycastle.asn1.DEROctetString;
  import local.org.bouncycastle.crypto.Digest;
  import local.org.bouncycastle.crypto.digests.SHA1Digest;
  
  /**
   * The SubjectKeyIdentifier object.
   * <pre>
   * SubjectKeyIdentifier::= OCTET STRING
   * </pre>
   */
  public class SubjectKeyIdentifier
      extends ASN1Object
  {
      private byte[] keyidentifier;
  
      public static SubjectKeyIdentifier getInstance(
          ASN1TaggedObject obj,
          boolean          explicit)
      {
          return getInstance(ASN1OctetString.getInstance(obj, explicit));
      }
  
      public static SubjectKeyIdentifier getInstance(
          Object obj)
      {
          if (obj instanceof SubjectKeyIdentifier)
          {
              return (SubjectKeyIdentifier)obj;
          }
          else if (obj != null)
          {
              return new SubjectKeyIdentifier(ASN1OctetString.getInstance(obj));
          }
  
          return null;
      }
  
      public static SubjectKeyIdentifier fromExtensions(Extensions extensions)
      {
          return SubjectKeyIdentifier.getInstance(extensions.getExtensionParsedValue(Extension.subjectKeyIdentifier));
      }
  
      public SubjectKeyIdentifier(
          byte[] keyid)
      {
          this.keyidentifier = keyid;
      }
  
      protected SubjectKeyIdentifier(
          ASN1OctetString keyid)
      {
          this.keyidentifier = keyid.getOctets();
      }
  
      public byte[] getKeyIdentifier()
      {
          return keyidentifier;
      }
  
      public ASN1Primitive toASN1Primitive()
      {
          return new DEROctetString(keyidentifier);
      }
  
  
      /**
       * Calculates the keyidentifier using a SHA1 hash over the BIT STRING
       * from SubjectPublicKeyInfo as defined in RFC3280.
       *
       * @param spki the subject public key info.
       * @deprecated
       */
      public SubjectKeyIdentifier(
          SubjectPublicKeyInfo    spki)
      {
          this.keyidentifier = getDigest(spki);
      }
  
      /**
       * Return a RFC 3280 type 1 key identifier. As in:
       * <pre>
       * (1) The keyIdentifier is composed of the 160-bit SHA-1 hash of the
       * value of the BIT STRING subjectPublicKey (excluding the tag,
       * length, and number of unused bits).
       * </pre>
       * @param keyInfo the key info object containing the subjectPublicKey field.
       * @return the key identifier.
       * @deprecated use org.bouncycastle.cert.X509ExtensionUtils.createSubjectKeyIdentifier
       */
      public static SubjectKeyIdentifier createSHA1KeyIdentifier(SubjectPublicKeyInfo keyInfo)
      {
          return new SubjectKeyIdentifier(keyInfo);
      }
  
      /**
       * Return a RFC 3280 type 2 key identifier. As in:
       * <pre>
       * (2) The keyIdentifier is composed of a four bit type field with
       * the value 0100 followed by the least significant 60 bits of the
       * SHA-1 hash of the value of the BIT STRING subjectPublicKey.
       * </pre>
       * @param keyInfo the key info object containing the subjectPublicKey field.
       * @return the key identifier.
       * @deprecated use org.bouncycastle.cert.X509ExtensionUtils.createTruncatedSubjectKeyIdentifier
       */
      public static SubjectKeyIdentifier createTruncatedSHA1KeyIdentifier(SubjectPublicKeyInfo keyInfo)
      {
          byte[] dig = getDigest(keyInfo);
          byte[] id = new byte[8];
  
          System.arraycopy(dig, dig.length - 8, id, 0, id.length);
  
          id[0] &= 0x0f;
          id[0] |= 0x40;
          
          return new SubjectKeyIdentifier(id);
      }
  
      private static byte[] getDigest(SubjectPublicKeyInfo spki)
      {
          Digest digest = new SHA1Digest();
          byte[]  resBuf = new byte[digest.getDigestSize()];
  
          byte[] bytes = spki.getPublicKeyData().getBytes();
          digest.update(bytes, 0, bytes.length);
          digest.doFinal(resBuf, 0);
          return resBuf;
      }
  }
  