A method of certification of an electronic contract, the method comprising: • access on the part of a transmitter to a contract server of a telecommunications operator, • uploading the electronic contract to be signed to said contract server, • introduction of data of a receiver, user of a receiving entity, where said data comprise at least one of: recipient email address and recipient telephone number, • selecting a recipient telephone number or recipient email address, • sending to the receiver: an SMS by means of a certified SMS server or a certified email by means of an email management server where both the certified SMS and the certified email comprise at least one URL which links to a proxy server of a certification authority, CA, server by means of which all the communication is carried out, • access on the part of the receiver to said URL and selection of a digital certificate to be used in the transaction, and • access on the part of the receiver to the contract server by means of the proxy server of the CA to verify data contained in the digital certificate, the method further comprising: • a verification of data contained in the digital certificate by means of a comparison so that the identity of the recipient is ensured, • storing the content of the original email and any attachments in a database server of the telecommunications operator, • showing the electronic contract to the recipient once the identity of the recipient is ensured, • signing of the contract by the recipient, • sending a copy of the signed contract to the recipient, • generation of evidence by the evidence generation server, • generating, by means of the evidence generation server, a transaction certificate with all the network data, the contract, the documents generated by the proxy server of the CA and transactional data of the operation used, • signing the certificate of the transaction with a digital signature of the telecommunications operator, • applying time stamps by means of a time stamp server to the certificate of the transaction once it has been signed, and • sending at least two copies of the signed and stamped certificate of the transaction and all generated evidence, one to the transmitting entity and another to the receiving entity in order to be collected by their respective users. • access on the part of a transmitter to a contract server of a telecommunications operator, • uploading the electronic contract to be signed to said contract server, • introduction of data of a receiver, user of a receiving entity, where said data comprise at least one of: recipient email address and recipient telephone number, • selecting a recipient telephone number or recipient email address, • sending to the receiver: an SMS by means of a certified SMS server or a certified email by means of an email management server where both the certified SMS and the certified email comprise at least one URL which links to a proxy server of a certification authority, CA, server by means of which all the communication is carried out, • access on the part of the receiver to said URL and selection of a digital certificate to be used in the transaction, and • access on the part of the receiver to the contract server by means of the proxy server of the CA to verify data contained in the digital certificate, the method further comprising: • a verification of data contained in the digital certificate by means of a comparison so that the identity of the recipient is ensured, • storing the content of the original email and any attachments in a database server of the telecommunications operator, • showing the electronic contract to the recipient once the identity of the recipient is ensured, • signing of the contract by the recipient, • sending a copy of the signed contract to the recipient, • generation of evidence by the evidence generation server, • generating, by means of the evidence generation server, a transaction certificate with all the network data, the contract, the documents generated by the proxy server of the CA and transactional data of the operation used, • signing the certificate of the transaction with a digital signature of the telecommunications operator, • applying time stamps by means of a time stamp server to the certificate of the transaction once it has been signed, and • sending at least two copies of the signed and stamped certificate of the transaction and all generated evidence, one to the transmitting entity and another to the receiving entity in order to be collected by their respective users.