Digital Signature·Electronic Contract Service ICERTI4U I CERTI 4U is a service provided as a PDF document by applying the high-strength forgery prevention function of the contract by adding a high-density 2D barcode to the signed contract and adding digital signature and timestamp information. [Key Services Content] I CERTI 4U provides the contract documents signed by Off-line as electronic documents with the addition of 2D bar code, digital signature and timestamp. [Service Procedures]