DER File – What is .der file and how to open it?

DER File Type and Usage:

A DER file is a binary data format used for encoding X.509 digital certificates and other cryptographic information in a standard and portable manner. Developed by the International Telecommunication Union (ITU) as part of the X.509 standard, DER stands for “Distinguished Encoding Rules.” It defines a specific format for representing and transmitting certificates, public keys, and other digital objects in a compact and efficient manner. DER files are commonly used in various cryptographic applications, such as digital signatures, encryption, and authentication.

File Structure and Features:

DER files consist of a binary sequence of bytes that adhere to a specific encoding scheme. The data is structured using a hierarchical tagging system, where each field is tagged with a type and a length. DER employs a type-length-value (TLV) encoding mechanism, where each field is encoded as a tag, followed by the length of the field, and then the value of the field. This structured encoding allows for efficient parsing and interpretation of the certificate data. DER files are widely supported by various software applications and cryptographic libraries, making them a common choice for storing and exchanging digital certificates and related cryptographic information.

DER Digital Certificate

Digital certificates (.DER) follow the Distinguished Encoding Rules (DER) standard, which requires their content to be encoded using a specific binary format. This ensures that the certificates can be exchanged and understood by different systems and applications. These certificates hold essential information related to digital signatures, public keys, and other cryptographic details.

Opening DER Files

DER files can be opened with several software tools that support the DER format. Here are two methods to open a DER file:

• Using OpenSSL:

  • Install OpenSSL on your system.
  • Open the command prompt and navigate to the DER file’s directory.
  • Enter the command openssl x509 -in filename.der -text to view the certificate’s details.

• Using a Certificate Viewer:

  • Download and install a certificate viewer such as DigiCert Certificate Utility or OpenSSL CA Certificate Manager.
  • Open the certificate viewer and click on the “Open” button to select the DER file.
  • The certificate’s information, including its validity, subject, issuer, and public key, will be displayed.

DER File Format

DER (Distinguished Encoding Rules) is a binary encoding format for representing digital certificates. It is defined in the ITU-T X.690 standard and is widely used in a variety of applications, including secure electronic mail, SSL/TLS, and electronic signatures. DER files contain a sequence of ASN.1 (Abstract Syntax Notation One) objects, which are encoded using a specific set of rules. The DER encoding rules ensure that the resulting file is compact and efficient to transmit.

Applications of DER Files

DER files are used in a variety of applications:

• Secure electronic mail: DER files are used to encode digital certificates that are used to authenticate email senders and recipients. This helps to prevent email spoofing and phishing attacks.
• SSL/TLS: DER files are used to encode digital certificates that are used to secure web connections. This helps to protect sensitive data, such as passwords and credit card numbers, from being intercepted by attackers.
• Electronic signatures: DER files are used to encode digital signatures that are used to verify the authenticity and integrity of electronic documents. This helps to ensure that documents have not been tampered with or altered.

Other Extensions