Time Stamping Protocol (TSP)

The Time Stamping Protocol (TSP) is a cryptographic protocol used to provide trusted and verifiable timestamps for digital documents and transactions. It ensures that the timestamp is securely generated, tamper-proof, and can be independently verified by third parties. TSP is defined in the Internet Engineering Task Force (IETF) Request for Comments (RFC) 3161.

Here are key aspects of the Time Stamping Protocol (TSP):

1. Timestamp Generation: TSP allows individuals or organizations to generate timestamps for digital documents or other data. The timestamp is a digital signature that binds the data to a specific point in time. It provides evidence that the data existed and was unchanged at that particular time.
2. Trusted Time Source: TSP relies on trusted time sources, often referred to as Time Stamping Authorities (TSA). These authorities are responsible for generating and signing the timestamps. A TSA typically obtains the time from reliable sources such as atomic clocks or global time synchronization systems.
3. Cryptographic Signatures: TSP utilizes cryptographic techniques to sign the timestamp and ensure its integrity. The TSA digitally signs the timestamp using its private key, and the recipient can verify the signature using the TSA’s public key. This process allows anyone to independently verify the authenticity and integrity of the timestamp.
4. Non-Repudiation: TSP provides non-repudiation, meaning that the party generating the timestamp cannot deny its involvement. Since the timestamp is signed by the TSA’s private key, it can be used as evidence in legal or contractual disputes.
5. Timestamp Verification: TSP supports the verification of timestamps by third parties. Any party can validate the timestamp’s integrity by verifying the TSA’s digital signature. The verification process ensures that the timestamp has not been tampered with and that the data existed at the specified time.
6. Integration with Digital Signatures: TSP can be integrated with digital signature mechanisms to create time-stamped digital signatures. This allows the signing of documents with a timestamp, providing additional evidence of the document’s authenticity and integrity at a specific time.

TSP is used in various applications where a trusted and verifiable timestamp is required. It is commonly used in legal, financial, and regulatory contexts, where the accurate timing of events or the proof of existence of specific data at a particular time is critical.

It’s important to note that TSP is not widely implemented compared to other security protocols. However, its principles and concepts have influenced other timestamping mechanisms and protocols used in different domains, such as blockchain-based timestamping systems.

The Time-Stamp Protocol, or TSP is a cryptographic protocol for certifying timestamps using X.509 certificates and public key infrastructure. The timestamp is the signer’s assertion that a piece of electronic data existed at or before a particular time. The protocol is defined in RFC 3161. One application of the protocol is to show that a digital signature was issued before a point in time, for example before the corresponding certificate was revoked.

The TSP protocol is an example of trusted timestamping. It has been extended to create the ANSI ASC X9.95 Standard.

Protocol[edit]

In the protocol a Time Stamp Authority (TSA) is a trusted third party that can provide a timestamp to be associated with a hashed version of some data. It is a request-response protocol, where the request contains a hash of the data to be signed. This is sent to the TSA and the response contains a Time Stamp Token (TST) which itself includes the hash of the data, a unique serial number, a timestamp and a digital signature. The signature is generated using the private key of the TSA. The protocol can operate over a number of different transports, including email, TCP sockets or HTTP.

When presented with a TST, someone may verify that the data existed at the timestamp in the TST by verifying the signature using the public key of the TSA and that the hash of the data matches that included in the TST.