Repository of Timestamp Public Key Certificates, Policy and License
Contents
- End-user license agreement
- Incident reports that could impact verification of timestamps
- Current Public Key certificates
- History of Public Key certificates
- Root certificate and how public keys are organized
- Web addresses / URL for timestamp servers
- Test / Evaluation TSA public key certificates
Current Timestamp public keys
We replace certificates and signing keys about every 6 months. The prior / older Public Key certificates are here.
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Timestamp public key certificate for " TSA 1 "
- Server's External Audit certificate DGS92.cer
- Timestamp certificate DGS92.32771.cer (new as of May 8, 2012)
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Timestamp public key certificate for " TSA 2 "
- Server's External Audit certificate DGS91.cer
- Timestamp certificate DGS91.32780.cer (new as of February 16, 2012)
Root Certificate
The public keys are provided for independent verification of the timestamps created by the DigiStamp timestamp servers. Each public key is provided as a standard x.509 certificate. The public keys are used to verify the digital signature contained in a timestamp. These certificates are commonly contained within each timestamp and they are also provided here for convenience.
Click here for additional information about what you need to verify a timestamp.
Timestamp server Root Certificate
The root certificate can be downloaded and added to your software. For example, import the certificate to your Internet browser or Adobe Acrobat signing tools.
The DigiStamp root certificate:
The certificate's SHA-1 valueis used for confirmation in some software:
9a048ed85eec7c802eebbbb7c91792d7aae45136
Alternatively, the Root Certificate and collection of Server Audit Certifcates can be downloaded in a single PEM file digistamp.pem.
To review your options for integrating the chain of authority of these certificates with your enterprise CA then click here.

Timestamp key life cycle
The timestamp key-pairs are replaced frequently within the certified hardware device. The frequency is one year or after one million timestamps are created with the key-pair. Each event of "rekeying of the TSA key" results in the cryptographic module creating and signing a new x.509 public key certificate. The previous timestamp private key is destroyed at the time of rekeying. The timestamps created with that private key are authenticated using the x.509 public key certificate. More details are here where we describe that the timestamp private key cannot be extracted from the certified hardware device.
Names and addresses of the Timestamp Servers
The time stamp servers are available to generate production time stamps:
"TSA1" - https://tsa1.digistamp.com/TSA at IP address 66.18.15.156
"TSA2" - https://tsa2.digistamp.com/TSA at IP address 199.192.203.90
The above servers use HTTP authentication to your DigiStamp account. Use of SSL (https:) is optional.
