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Securing e Government Public Key Infrastructure

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Presentation on theme: "Securing e Government Public Key Infrastructure"— Presentation transcript:

1 Securing e Government Public Key Infrastructure
Prof Dr Mohamed Kouta Chairman Of MIS Department Arab Academy For Science And Technology

2 Outline Security Requirements. Symmetric Key Cryptosystem.
Asymmetric (Public) Key Cryptosystem. Over View of Digital Signature. Secure Socket Layer Protocol. Digital Certificate. Certificate Authority. PKI Components. PKI Implementation. Using biometrics and Smart Token. PKI Assessment.

3 Security Requirements
Privacy. Authenticity. Non repudiation Integrity.

4 Symmetric Key Cryptosystem Consider a key length = 4 Key = BAND
Poly alphabetic Cipher Consider a key length = 4 Key = BAND A B C D E F G H I J K L M N O P Q R S T U V W X Y Z Plain Text M= E BUS INES S B AND BAND B Cipher Text E(M)= G CIW KOSW U

5 M C Symmetric-key Cryptosystems Es Ds Sender Receiver Secret Key
Overview Symmetric-key Cryptosystems Encryption Es Decryption Ds Sender Receiver M C Secret Key Secure Channel Intruder

6 M C Symmetric-key Cryptosystems Es Ds Sender Receiver Secret Key
Overview Symmetric-key Cryptosystems Encryption Es Decryption Ds Sender Receiver M C Secret Key Secure Channel Intruder

7 M C Asymmetric-key Cryptosystems EK DK Sender Receiver Public Key
Overview Asymmetric-key Cryptosystems Encryption EK Decryption DK Sender Receiver M C Public Key Private Intruder

8 Overview of Digital Signature
Signer’s Private Key Encrypted Digest Digest Signed Document Hash Algorithm Remember, a digital signature involves services provided by Certificate Authority (CA)

9 Verifying the Digital Signature for Authentication and Integrity
Digest ? Hash Algorithm Digest Signer’s Public Key And so does the process of verifying the validity of a digital signature

10 Sender’s Private Signature Key
Sender’s Computer Sender’s Certificate + Message Digital Signature Message Message Digest Sender’s Private Signature Key Receiver’s Certificate Encrypt Symmetric Key Encrypted Message Receiver’s Key-Exchange Key Encrypt Digital Envelope 10 © Prentice Hall, 2000

11 Receiver’s Computer   +   
Digital Envelope Receiver’s Private Key-Exchange Key Decrypt Decrypt Symmetric Key Encrypted Message Sender’s Certificate + Message Message Digest compare Message Digest Digital Signature Sender’s Public Signature Key Decrypt 11 © Prentice Hall, 2000

12 Digital Certificate X509 Standard Each certificate contains the
public-key of a user and is signed with the private-key of a trusted certificate authority

13 Certificate Authority
In an uncontrolled system, anyone could publish a new public-key and assume a new identity. Any Participant can send his public-key to any other one broadcast the key

14 Certificate Authority
This would be like allowing anyone to issue his or her own passport or driving licenses This is clearly unacceptable for any application that, like electronic commerce, requires authentication and non-repudiation. In order to assure a proper information exchange mechanism, an important entity should be involved in the process which is the Certificate Authority (CA).

15 Certificate Authority
Cont. Distribution of Public Keys Public key Certificate

16 Certificate Authority
Requirements of setting up the CA Compatibility with existing Internet based Certificate Authorities It should be possible to use the certificates in applications such as Netscape navigators, secure , and custom built business-to-business e-commerce applications. Certificates must be consistent with accepted standards; such the widely recognized X.509 certificate formats.

17 Certificate Authority
Effective Distribution mechanisms Directory server support:- includes client certificates, and certificate validity status. Certificates accompanying signatures:- The certificate, being signed by the ECA, enables the receiving party to check the validity of both the certificate, and the accompanying signature. Support for certificate revocation:-

18 Certificate Authority
Revocation of Certificates The user’s private key is compromised The user is no longer certified by this CA The CA’s certificate is compromised

19 CA never sees the private key
Certificate management cycle Request certificate for key linked with LIR ID Program Certificate Authority Certificate Revocation request Certificate is included in the Certificate Revocation List (CRL) Request a certificate Send browser form Send public key Certificate User CA never sees the private key Certificate Some time later the user wants to revoke the certificate…

20 PKI Component Certificate Authority (CA).
Issues Digital Certificates Authorization Authority (AA). Response for Digital Certificate (DC) request Registration Authority (RA). Contains a database for DC and Certificate Revocation List CRL. Directory Services. Handles DC exchange. Applications.

21 PKI Implementation Issuing the Certificate Practice Statement (CPS).
A statement of Practices that CA employs in issuing DC. Building the PKI as according CPS. Training for users and administration Staff. Connections to secured systems that could circumvented the PKI must be ended. Integration with the different applications.

22 Using Biometrics and Smart Token in Electronic signature

23 How a citizen can apply for a Smart Token
Step 1 The citizen (Applicant A) provides his National Security Number Card (NSN) to one of the Service Provider (SP). Step 2 SP sends the NSN information to the CA. Step 3 CA checks for Applicant already has a DC or revoked with RA. Step 4 If A is applying first time, CA asks for authorization from AA. Step 5 AA responses for CA. Step 6 CA asks A to generate his keys pair. Step 7 The Two pairs are generated inside the applicant smart Token. Step 8 The public Key is sent to the CA. Step 9 The CA generates and sends the DC back to the applicant Token. Step 10 The token is trained for the applicant finger print.

24 Sender side Pre Session Stage CA Sender (S) Receiver (R)
2 check validity Sender (S) Receiver (R) 1 S wants to communicate with R 3 SDC 3 RDC

25 Sender side Sender PC Sender Token Sender Data
1- Selecting the message M to be sent from the sender PC (SPC). 2- According to the Hashing Algorithm (HA) stored in the SPC , M will be hashed and the message digest (MD) will be generated. 3- The message digest MD is transferred from the SPC to the sender Smart Token (SST). 6- Using a random number generator (RNG), a session key (SK) will be generated inside the SPC. 7- Encrypting M+SDS+SDC using symmetric key encryption algorithm SKEA and Sk as encryption key and call it the encrypted signed message (ESM). 8- Extracting the receiver public key (RPUK) from the RDC available in the SCL. 9- Encrypt the SK with RPUK using PKUK to create Digital Envelop (DE) send ESM+DE. Sender Token MD 4- Using public key cryptographic algorithm (PKCA) ,the MD is encrypted with the sender private key (SPRK) to get the sender digital signature (SDS). 5- The SDS+ a copy from the sender digital certificate (SDC) are sent back to the SPC. Sender Data SDS SDC ESM + DE

26 Sender side Third Process Sender PC Receiver PC ESM + DE
Encrypted Signed message (ESM) Encrypted session key By receiver public key (DE) Sender PC ESM + Receiver PC

27 Receiver side Receiver PC Receiver Token 2- Using PKEA the DE
1-DE is sent to the receiver smart token (RST). 4- By the SK the message will be Decrypted using the same SKEA Now we have : M+ SDS + SDC. 5- The SDC received from CA is compared with SDC received from the sender to assure its validity. If its valid the procedure continue , aborted otherwise. 6- Decrypt the SDS by the sender public key SPUK contained in the SDC to get MD. Call it MD1. 8- Using M generate a message digest MD using the same HA. Call it MD2. 7- Compare the two digests MD1 and MD2. If MD1 and MD2 are identical then message accepted otherwise the message is rejected. Receiver Token 2- Using PKEA the DE is Decrypted by the RPRK to get the session key SK. 3- Send SK back to the RE PC DE Received Data SK ESM + DE

28 Token blank contain 1- RSA Encryption/decryption Algorithm.
2- USB Interface. 3- Biometric sensor. 4- Image processing. 5- Feature extraction & recognition. 6- ROM. 7- RAM

29 Token Block Diagram Smart Token Block Biometric Device
Interface Bus USB including power supply

USB interface BUS Biometric Interface ROM Private Key Certificate contain Public Key Finger print of the owner RAM Processing and result storage RSA En /Dec Algorithm & Key Generation Biometric Device Interface Bus Power supply from USB Control unit Feature extraction & recognition Image processing USB BUS

31 Biometric Verification for Smart Token

32 AT77C101B-CB02V Sensor

33 Architecture of the automatic identity authentication system

34 Image processing and extraction of fingerprint minutia

35 Step (1) Input Image

36 Step (2) Region of Interest

37 Step (3) Orientation Field

38 Step (4) Ridge Detection
Ridge ending and ridge bifurcation.

39 Step (5) Extracted Ridges

40 Step (6) Thinned Ridges

41 Step (7) Smoothing procedure
• The presence of undesired spikes and breaks present in a thinned ridge map may lead to many spurious minutiae being detected. • Therefore, before the minutiae detection, a smoothing procedure is applied to remove spikes and to join broken ridges.

42 Step (8) Minutiae detection

43 Last Step Minutia Extraction


45 Minutiae Matching Alignment of the input ridge and the template ridge

46 Applying the matching algorithm to an input minutiae set and a template
(a) input minutiae set (b) template minutiae set

47 Applying the matching algorithm to an input minutiae set and a template (Cont.)
(d) matching result where template minutiae and their correspondences are connected by green lines. (c) alignment result based on the minutiae marked with green circles

48 PKI Assessments CPS CA AA RA CRL policies.
Certificate Usage with applications. Auditing. Cryptographic devices and data Cryptographic Algorithms Critical Information Flow. Sensitive Software Applications. Key Managements. Network Devices Hosts, Routers, firewalls, switches).

49 Examples for PKI applications
. E-Gov services (Pension, ..). E-Election (voting). Group decision making. Multi signature. Notarizing. E-payment. Medical care. Note: It is up to the application to deploy the smart token.

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