Electronic Digital Signature


Traditions of encryption date back to ancient times: it was emperor Julius Caesar who invented the code named after him.  However, the history of electronic digital signatures is not that long.

Electronic digital signature  is a succession of symbols which appeared as a result of cryptographic transformation of electronic data.

It is added to data block and allows the block receiver check the source and data integrity and protect oneself against the counterfeits.  It can also be used as an analogue of a personal signature.

As a rule, the scheme of an electronic signature includes the algorithm of generation of the user’s key pairs, identification function and function of a signature verifying. The function of signature identification by a user’s document and secret key identifies the signature itself, and the function of a signature verifying checks if the signature corresponds to the document and open user’s key. User’s open key is available for everybody.

There is a difference between an electronic digital signature and the authentic message code, though both of them have similar aims (provision of a document’s integrity and impossibility of repudiation). The algorithms of electronic digital signature are asymmetric algorithms, whereas the codes of authenticity are calculated in accordance with the symmetric schemes.

Digital signature gives the opportunity to:

• ascertain the source of a document
• protect against the document changes
• make the repudiation impossible
There are some digital signature risks:
• signature forging
• an attempt to get an appropriate document to a signature, so that it correspond to the document
• forging of a counterfeit document with the same hash as the authentic document
• possibility of signing any document by an intruder stealing the closed key on behalf of the key owner
• intruder can make an owner sign a document by deception (for instance, by using the blind signature protocol)
• possibility of an intruder’s substitution of an owner’s key for his own to act as the owner

There are several algorithms of a digital signature, among them are:

• American standards of an electronic digital signature (DSA; ECDSA)
• Russian standards of an electronic digital signature (ГОСТ Р 34.10-94 – is not valid at present time; ГОСТ Р 34.10-2001)
• Ukrainian standards of an electronic digital signature (ДСТУ 4145-2002)
• Standard PKCS#1 describes, in particular, the scheme of an electronic digital signature on the basis of  RSA algorithm.

The problem with cryptography with open key including the systems of electronic digital signatures is managing the open keys.  It is necessary to provide access to an authentic open key of any other user, protect the keys from substitution of an intruder and cancel the key in case it is compromised.  The keys are protected with the help of certificates.

The certificate allows verify the owner’s data and his open key with the signature of an authorized representative. The centralized certificate systems (PKI, for instance) apply the centres of certification supported by the authorized organizations. In decentralized systems (PGP, for instance) every user builds up a network of trust of people.

The centres of certificate distribution control the keys. In such centre a user can get a certificate of some other user and check if any of the opened keys has been cancelled.

In Russia a legal certificate of an electronic signature is issued by the certificate centre.  The legal conditions of a n electronic digital signature usage are regulated by the Federal Law issued on January 10, 2002 № 1-ФЗ “On the electronic digital signature”.

After the digital handwriting was established and application of documents between the credit organizations and credit bureaus in electronic circulation in 2005 the infrastructure of the electronic records management between the rating authorities and tax-payers started to develop. The order of the Ministry of the Russian Federation for Taxes and Tallage (April 2, 2002 No БГ-3-32/169) “The procedure of filing an electronic tax statement by interchange carriers”. The document outlines the general principles of information exchange when the tax-payers provide their tax statements by interchange carriers.

The system of digital signatures is widely used in Estonia where 75% of citizens have ID cards. In March 2007with the help of electronic signatures there were held the elections to the Estonian Parliament (Riigikogu) when over 400, 000 people applied their digital signatures during the election.

Besides, with the help of an electronic signature one can send a tax statement, customs declaration, various blanks to local and state structures; and in large cities it is even possible to buy a monthly bus ticket with an ID card. Estonian ID cards are compulsory for all the residents older 15 living in Estonia either permanently or temporarily.

Federal Law of the Russian Federation on electronic digital signature

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