<p>Although the blockchain as it is used in Bitcoin is a new and novel concept, the idea of a chain of blocks in the field of cryptography goes back to symmetric block cipher modes of operation.  Specifically, the common practice of <a href="http://searchsecurity.techtarget.com/definition/cipher-block-chaining" rel="nofollow">cipher block chaining</a>.  This practice was first described in <a href="http://csrc.nist.gov/publications/fips/fips81/fips81.htm" rel="nofollow">a standard from 1981</a>, although it was almost certainly in use before then.</p>

<p>Although cipher block chaining is fundamentally different than the chain of blocks that Bitcoin uses, it is an example from cryptography where a change to an earlier block affects all subsequent blocks.</p>

CC BY-SA 3.0
2016-04-05T13:47:36.423Z
2016-04-05T13:47:36.423Z
Jestin
<p>According to <a href="https://freedom-to-tinker.com/blog/randomwalker/the-princeton-bitcoin-textbook-is-now-freely-available/" rel="noreferrer">Bitcoin and Cryptocurrency Technologies (BaCT)</a>, the Princeton Bitcoin textbook, the block chain dates back to a "paper by Haber and Stornetta in 1991. Their proposal was a method for secure timestamping of digitaldocuments, rather than a digital money scheme." (BaCT p.15)</p>

<p>The chaining of Merkle trees instead of single documents was proposed in a later paper. (BaCT p.16)</p>

CC BY-SA 3.0
2016-04-05T10:53:16.700Z
2016-04-05T10:53:16.700Z
Murch
<p>With bitcoin's blockchain, each block's hash is computed with the previous block's hash. That makes all blocks an immutable chain.</p>

<p>This is not the first time people used a hash-chain. As far as I know, Git was already used it since 2005 for the commit-hash computing.</p>

<p>So, what is the earliest use of hash chains? Where did the idea of blockchain come from? </p>

<blockchain><hash><history>
Where did the idea of blockchain come from? Git was already using it since 2005
jiedo
# Where did the idea of blockchain come from? Git was already using it since 2005

(Asked by: username_0 on 2016-04-05)

With bitcoin's blockchain, each block's hash is computed with the previous block's hash. That makes all blocks an immutable chain.

This is not the first time people used a hash-chain. As far as I know, Git was already used it since 2005 for the commit-hash computing.

So, what is the earliest use of hash chains? Where did the idea of blockchain come from?

**Tags:** blockchain, hash, history


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## 2 answers

### Answer by username_2 on 2016-04-05. Score: 9 | Accepted answer

According to [Bitcoin and Cryptocurrency Technologies (BaCT)](https://freedom-to-tinker.com/blog/randomwalker/the-princeton-bitcoin-textbook-is-now-freely-available/), the Princeton Bitcoin textbook, the block chain dates back to a "paper by Haber and Stornetta in 1991. Their proposal was a method for secure timestamping of digitaldocuments, rather than a digital money scheme." (BaCT p.15)

The chaining of Merkle trees instead of single documents was proposed in a later paper. (BaCT p.16)


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### Answer by username_1 on 2016-04-05. Score: 3

Although the blockchain as it is used in Bitcoin is a new and novel concept, the idea of a chain of blocks in the field of cryptography goes back to symmetric block cipher modes of operation. Specifically, the common practice of [cipher block chaining](http://searchsecurity.techtarget.com/definition/cipher-block-chaining). This practice was first described in [a standard from 1981](http://csrc.nist.gov/publications/fips/fips81/fips81.htm), although it was almost certainly in use before then.

Although cipher block chaining is fundamentally different than the chain of blocks that Bitcoin uses, it is an example from cryptography where a change to an earlier block affects all subsequent blocks.


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