<p>Why does a TSA first appends the timestamp and hashes the combination of timestamp and data? This product is then signed and send to the client back with the timestamp. Why not signing hash + timestamp?</p>

CC BY-SA 4.0
2019-09-16T15:05:34.787Z
What is a TSA? What protocol or system is this question about?
Pieter Wuille
CC BY-SA 4.0
2019-09-17T15:55:27.747Z
@PieterWuille Trusted Time Stamping. TSA is Timestamping Authority.
user674907
CC BY-SA 4.0
2019-09-17T15:56:46.330Z
I don't know about that, but a quick search tells me you're maybe talking about RFC 3161? If so, that seems off topic here.
Pieter Wuille
CC BY-SA 4.0
2019-09-17T16:37:35.620Z
@PieterWuille
Yeah. this is the protocol. But I do not understand the design choise.
user674907
CC BY-SA 4.0
2019-09-17T16:38:14.597Z
This seems unrelated to Bitcoin.
Pieter Wuille
CC BY-SA 4.0
2019-09-17T16:40:02.563Z
I thought this stackexchange is about everything dealing with consensus, byzantine, trusting third parties, etc. ... (everything bitcoin is built on)?
user674907
CC BY-SA 4.0
2019-09-17T16:41:29.190Z
It is about technologies that apply to supporting the bitcoin currency. Timestamping in an abstract sense certainly does, but not the specifics of RFC 3161, which is unrelated to how timestamping services for Bitcoin work.
Pieter Wuille
CC BY-SA 4.0
2019-09-17T16:43:22.687Z
If u go to wikipedia page: https://en.wikipedia.org/wiki/Trusted_timestamping
It seems like a general concept. I just want to know if I forget something, or about advandatages, such a design choice has.
Maybe privacy, scalability, ... I do not know. :/
user674907
<timestamp><trust>
TSA: Why singing hash(hash(data),t)?
user674907
# TSA: Why singing hash(hash(data),t)?

(Asked by: username_0 on 2019-09-16)

Why does a TSA first appends the timestamp and hashes the combination of timestamp and data? This product is then signed and send to the client back with the timestamp. Why not signing hash + timestamp?

**Tags:** timestamp, trust

> **Comments:**
> **username_1**: What is a TSA? What protocol or system is this question about?  
> **username_0**: @PieterWuille Trusted Time Stamping. TSA is Timestamping Authority.  
> **username_1**: I don't know about that, but a quick search tells me you're maybe talking about RFC 3161? If so, that seems off topic here.  
> **username_0**: @PieterWuille Yeah. this is the protocol. But I do not understand the design choise.  
> **username_1**: This seems unrelated to Bitcoin.  
> **username_0**: I thought this stackexchange is about everything dealing with consensus, byzantine, trusting third parties, etc. ... (everything bitcoin is built on)?  
> **username_1**: It is about technologies that apply to supporting the bitcoin currency. Timestamping in an abstract sense certainly does, but not the specifics of RFC 3161, which is unrelated to how timestamping services for Bitcoin work.  
> **username_0**: If u go to wikipedia page: https://en.wikipedia.org/wiki/Trusted_timestamping It seems like a general concept. I just want to know if I forget something, or about advandatages, such a design choice has. Maybe privacy, scalability, ... I do not know. :/  

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## 0 answers

