Validation of Functionality against Requirements

Functional requirements listed in section 5.1.1 are validated as follows;

Authentication U

to U

(Service Provider)

As seen in two first solutions that U2requests U1to authenticate, and U1is directed

to U₂0s authentication page. For sending U1to U20s authentication page the redirect

method will be used. U1 utilizes one of the eID provider and authenticates to U2.

The authentication data will be sent directly to U2and U1will be redirected back

to U₂0s web site. According to the technologies and standards presented in section 2, implementing these service are not impossible, though authentication of U1 to

U2is also possible.

Performing the Signature and Verification of it

The system carries out both signature and verification. As seen in section 4.1 both users and proxy signers are capable of verification. For signing, the system uses the PKC which is the most strong encryption solution in today’s technology [76]. For verification the system adds public key certificate of users and proxy certificate of proxy signers to DSS of the PDF document. Since proxy certificate is extended from user’s public key certificate, then signature can be validated by both certifi- cates. Adding proxy certificate is adequate, then why adding user’s public key certificate? The main reason is that if proxy certificate is revoked then the verifier has at least another certificate, original signer’s certificate, to verify the signature. Actually the signature is connected to original signer (users) so users’ public key certificate must be added to the DSS in the PDF document. As argued above that solution proposals can carry out signature and verify a signature, and thus the requirement is satified.

Validation of certificates embedded in the document

As presented previously that there are two mechanisms for checking the status of the certificates, thus Certificate Revocation List (CRL) and Online Certificate Sta- tus Protocol (OCSP). The former method is used where the system can tolerate time delay and latter is utilized when time delay is not acceptable. The system uses these methods to validate certificates. Since these mechanisms are widely used in enterprises, and work without any shortcoming, it should also be working in proposed solutions. The above arguments are adequate for validating this func- tionality.

Protecting Confidentiality and Integrity of Document

The integrity of the document is achieved through signature embedded in the doc- ument. Formatting standards is utilized for protecting the signature, thus protect- ing the integrity of the document. Confidentiality is achieved through SSL/TLS mechanisms. These mechanisms are widely used in today’s web technologies where security is also a goal. For instance, in bank industries SSL/TLS security is also used in normal web browsing. When entering to Internet banking it is obviously that the confidentiality of data exchanged between user and bank is encrypted. Proposed solutions provides both integrity and confidentiality of the document, thus this requirement is achieved and validated.

Protecting Long Term Validation

Long term validity is desirable of this project. This thesis’s solution proposals provide long term validity of the signed document. This is achieved by using the ETSI standard ETSI TS 102 778 which is extended from ISO 32000 standard [25]. These standards are well known and widely used in the Internet. Based on ETSI standard, the system will provide long term validation of the document, thus this

functionality is approved.

Identifying the Signatory

Identifying the signatory is mandatory according to the definition of advanced elec- tronic signature. PKI made it possible to achieve this goal of thesis. Public key certificate, certified by CA and embedded in the document, binds the owner’s, i.e. the signatory, identity to the certificate [76]. Using PKI, thus public key certificate in signature, links the certificate to the owner (signatory), and thereby connect the signature to the signatory, will validate this requirement.

Usability Speed

As mentioned previously that in software developing process if the security is a priority, then usability will be weakened. Although usability is a non-functional requirement, it is considered in the proposed solutions. It seems that usability in these solutions will be weak. Since heavy cryptographic operations will be carry out during the signing, then the speed will be slow, and thus this will cause a poor usability. The usability will be as good as it can be validated, so usability in this level will be accepted as adequate.

Availability Reliability

The availability means that the system must be available all the time. This require- ment can be validated adding redundant entities such that if one is down the other do the job. It is believed that the availability will be achieved as desired. Reliabil- ity means that the expectation of error occurring must not exceed the threshold. Redundancy will improve the reliability of the signature system. It is assumed that both reliability and availability requirements could be handled well, if the system could have been implemented. It is further assumed that the system will satisfy the minimum requirements of reliability and availability. Thus, these requirements are assumed to be validated.

Cost Effectiveness

Cost effective means that deployment and implementation of a system is cheap and easy. As seen that most of the existing technologies and mechanisms are utilized and therefore the system deployment and implementation will not be difficult. For instance, in 3rd solution proposal Mail archive is already existed. Therefore this requirement is also validated.