Class DerUtils

java.lang.Object
de.xima.fc.model.encoding.DerUtils
public class DerUtils extends Object
Since:
8.5.4
Author:
Norman Lorenz

  • Method Details

    • decodeDerStringValue

      public static String decodeDerStringValue(byte[] derBytes)
      Decodes a DER-encoded (Distinguished Encoding Rules per ITU-T X.690) ASN.1 string value into a plain Java String.

      This method expects the input byte array to contain a complete TLV (Tag-Length-Value) structure as used in ASN.1 DER encoding:

      • Tag (1 byte): ASN.1 type identifier (e.g., 0x16 for IA5String)
      • Length (1+ bytes): Short form (0x00–0x7F) or long form (0x80–0xFF)
      • Value (n bytes): The actual string content

      Charset selection:

      Common use case: Decoding RFC 2253 hex-encoded DN attributes. When Java's X500Principal outputs a DN with email attributes (e.g., 1.2.840.113549.1.9.1=#1623...), the hex part after # represents the DER-encoded value. This method decodes such values.

      Parameters:
      derBytes - the complete DER-encoded TLV byte array (must not be null or empty)
      Returns:
      the decoded string value
      Throws:
      IllegalArgumentException - if:
      • derBytes is null or shorter than 2 bytes
      • the length field is malformed or inconsistent with the actual payload
      • the DER structure violates basic format rules
      Since:
      8.5.4
      See Also: