Some timestamp formats are shown in the following examples, where y stands for year, d for day, h for hour, m for minute and s for second: Timestamp formats are different across OSes, programming languages, databases and data types. Timestamps vary depending on the medium in which they're used. TSAs use public key infrastructure - the processes and technologies that enable encryption and data signing - to ensure their timestamps are valid and secure from manipulation. These third parties are known as Time Stamping Authorities. A trusted third party may generate a timestamp for the document instead of using the time from the machine on which the document is stored. Some timestamp uses, such as digital signatures, require a high level of reliability for legal reasons. Digital contracts and digital signatures use timestamps to show when a document was signed.
Data management relies on timestamps to ensure the integrity and quality of data.Blockchain blocks use timestamps to ensure the validity of transactions, such as with cryptocurrencies.Online chat and instant messages use timestamps to record the date and time when a message was sent, received or viewed.Social media posts include the date and time the post was made.Digital cameras attach timestamps to photographs that show the date and time of day a picture was taken.Computer files may contain a timestamp that shows when the file was last changed.The following are examples of how timestamps are used: A timestamp displays when certain information was created, exchanged, modified or deleted. Timestamps are used for keeping records of information online or on a computer. When writing a program, the programmer is usually provided an application programming interface for a timestamp that the operating system (OS) can provide during program execution. In IP telephony, for example, Real-time Transport Protocol assigns sequential timestamps to voice packets so that they can be buffered by the receiver, reassembled and delivered without error. Another way that a timestamp is used is to record time in relation to a particular starting point in time. The timestamp mechanism is used for a variety of synchronization purposes, such as assigning a sequence order for a multievent transaction so the transaction can be voided if a failure occurs. Such precision makes it possible for networked computers and applications to communicate effectively. Through mechanisms, such as the Network Time Protocol, a computer maintains accurate current time, calibrated to minute fractions of a second. A timestamp is the current time of an event that a computer records.