![Cryptography and Cyber Security
[IT311]
Sanjivani Rural Education Society’s
Sanjivani College of Engineering, Kopargaon-423603
(An Autonomous Institute Affiliated to Savitribai Phule Pune University, Pune)
NAAC ‘A’ Grade Accredited, ISO 9001:2015 Certified
Department of Information Technology
(NBAAccredited)
Mrs. Kanchan D. Patil
Assistant Professor](https://image.slidesharecdn.com/unit3digitalcertificateshared-250322160623-d897ecd3/85/Unit-3_Digital-Certificate_Intro_Types-pdf-1-320.jpg)
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Unit 3_Digital Certificate_Intro_Types.pdf
- 1. Cryptography and Cyber Security [IT311] Sanjivani Rural Education Society’s Sanjivani College of Engineering, Kopargaon-423603 (An Autonomous Institute Affiliated to Savitribai Phule Pune University, Pune) NAAC ‘A’ Grade Accredited, ISO 9001:2015 Certified Department of Information Technology (NBAAccredited) Mrs. Kanchan D. Patil Assistant Professor
- 2. Unit 3: Message Digest & Key Management • Hash Algorithms: SHA-1, MD5, Key Management: Introduction, Key Management: Generations, Distribution, Updation, Digital Certificate, Digital Signature, Kerberos 5.0. Cryptography & Cyber Security Mrs. Kanchan Patil Department of Information Technology
- 3. Digital Certificate • Introduction • Certification Authority • Contents of Digital Certificate • Digital Certificate Creation • Digital Certificate Verification • Certificate Types Cryptography & Cyber Security Mrs. Kanchan Patil Department of Information Technology
- 4. Digital Certificate : Introduction • A digital certificate is digital document that proves the authenticity of a device, server, or user through the use of cryptography and the public key infrastructure (PKI) such as driving license or passport. • It is small computer file with the name such as k.cer • The file extension can be different • Example: • Passport signifies the association between me and my other characteristics such as full name, nationality, date and place of birth, photograph and signature • Digital certificate simply signifies the association between my public key and me. Cryptography & Cyber Security Mrs. Kanchan Patil Department of Information Technology
- 5. Digital Certificate : Introduction • Digital Certificate must be approved by some authority in which all the concerned parties have a great amount of trust and belief. • A digital certificate establishes the relation between a user and her public key. Therefore, a digital certificate must contain the user name and the user's public key. • This will prove that a particular public key belongs to a particular user. Cryptography & Cyber Security Mrs. Kanchan Patil Department of Information Technology
- 6. Digital Certificate : Introduction • Subject Name: Any user's name in a digital certificate is always referred to as subject name. Because Digital Certificate can be issued to an individual, a group or an organization. • Serial number: We shall see what it means in due course of time. • Time: The certificate also contains other pieces of information, such as the validity date range for the certificate. • Issuer Name: who has issued it. Cryptography & Cyber Security Mrs. Kanchan Patil Department of Information Technology
- 7. Certification Authority • A Certification Authority (CA) is a trusted agency that can issue digital certificates. • The authority of acting as a CA has to be with someone who everybody trusts. • Consequently, the governments in the various countries decided who can and who cannot be a CA. • CA is a reputed organization, such as a post office, financial institution, software company, etc. • Famous CA: • VeriSign • Entrust Cryptography & Cyber Security Mrs. Kanchan Patil Department of Information Technology
- 8. Certification Authority • First Indian CA in February 2002 • Safescrypt Limited, subsidiary of Satyam Infoway Limited • CA has the authority to issue digital certificates to individuals and organizations, which war to use those certificates in asymmetric key cryptographic applications. Cryptography & Cyber Security Mrs. Kanchan Patil Department of Information Technology
- 9. Technical Details of Digital Certificate • A standard called as X.509 defines the structure of a digital certificate. • The International Telecommunication Union (ITU) came up with this standard in 1988. • The current version of the standard is Version 3, called as X.509V3. • The Internet Engineering Task Force(IETF) published the RFC2459 for the X.509 standard in 1999 Cryptography & Cyber Security
- 10. Technical Details of Digital Certificate • Contents of Digital Certificate shown in figure Cryptography & Cyber Security Mrs. Kanchan Patil Department of Information Technology
- 11. Technical Details of Digital Certificate • The figure shows the various fields of a digital certificate according to the X.509 standard. • It also specifies which version of the standard contains which fields. • Version 1 of the X.509 standard contained seven basic fields, version 2 added two more fields and version 3 added one more field. • These additional fields are called as extensions or extended attributes of version 2 and 3, respectively. • Of course, we have one additional common field in the end for all the versions. • Version 2 introduced two new fields to deal with the possibility that the Issuer Name (ie. the CA' name) and the Subject Name (i.e. the certificate holder's name) might be unintentionally duplicated over time. Cryptography & Cyber Security
- 12. Technical Details of Digital Certificate • However, the digital certificate standard (RFC2459) specifies that the same Issuer Name or the same Subject Name should never be used more than once in the first place. • Therefore, although these fields are added by version 2, their usage id discouraged and both these fields are made optional However, if used, these fields help distinguish between two issuers or subjects, if they are duplicated for some reason. • Version 3 of the X.509 standard has added many extensions to the structure of a digital certificate. Cryptography & Cyber Security
- 13. Fields in X.509 Digital Certificate V1 Cryptography & Cyber Security
- 14. Fields in X.509 Digital Certificate V2 Cryptography & Cyber Security
- 15. Fields in X.509 Digital Certificate V3 Cryptography & Cyber Security
- 16. Types of Digital Certificate • Depending on the requirement, the status and cost of certificate will differ. • For instance, a digital certificate can be used by a user only for encrypting messages, but not for digitally signing any messages. • In contrast, a merchant setting up its online shopping site may use a high- cost digital certificate, which covers many areas. • Generally, the certificate types can be classified as follows: • Email Certificates • Server-side SSL certificates • Client-side SSL certificates • Code-signing certificates Cryptography & Cyber Security
- 17. Types of Digital Certificate • Email certificates: • Email certificates include the user's email id. • This is used to verify that the signer of an email message has an email id that is the same as it appears in that user's certificate. • Server-side SSL certificates: • These certificates are useful for merchants who want to allow buyers to purchase goods or services from their online Web site. • Since a misuse of this certificate can cause serious damages, such certificates are issued only after a careful scrutiny of the merchant's credentials. Cryptography & Cyber Security
- 18. Types of Digital Certificate • Client-side SSL certificates: • These certificates allow a merchant (or any other server-side entity) to verify a client (browser-side entity). • Code-signing certificates: • Many people do not like to download client-side code such as Java applets or ActiveX controls, because of the inherent risks associated with them. • In order to alleviate these concerns, the code (i.c. the Java applets or ActiveX controls) can be signed by the signer. Cryptography & Cyber Security
- 19. Types of Digital Certificate • Code-signing certificates (continued): • When a user hits a Web page that contains such code, the browser displays a warning message, indicating that the page contains such pieces of code, signed by the appropriate developer/organization and whether the user would like to trust that developer/organization. • If the user responds affirmatively, the Java applets or ActiveX controls are downloaded and get executed on the browser. • However, if the user rejects the offer, the processing ends there. It must be noted that mere signing of code does not make it safe- the code could cause havoc. • It simply specifies where the code originates. Cryptography & Cyber Security
- 20. References: Cryptography & Cyber Security Mrs. Kanchan Patil Department of Information Technology • Atul Kahate,”Cryptography and Network Security”, second edition, Tata McGraw Hill