user93208: I found in https://www.bitcoincash.org/index.html that this technology is 
the world's most robust blockchain but searching for the details that explains why it is so secure I don't find any information. Some one knows a source that probes why this technology is secure and some technical information about the security implemented on it ?

user7272: As Nate mentioned, this is just a marketing statement. Any sane coin would try and promote themselves in this manner. Most are incorrect.
The most basic counter example being that many Bitcoin mining pools have enough hash power to perform a 51% attack on the Bitcoin cash chain. That alone is enough to not qualify it as the "World's most robust" chain.

user38618: I disagree with Chytrik: The hashrate and the number of miners are not the only factors that affect security. Here are some other factors:

Frequency of code review of nodes/wallets
Reputation of the companies who create wallet
The number of nodes in the network
Formal verification of software
How well-documented the protocol is (in long term)
Frequency of breaking changes (and other changes)
Code readability and simplicity
Whether software is signed before signed

Which means security is hard to measure.
If you had 1 BTC a year before, and today you open the wallet for the second time and that 1 BTC is still there, miners are not whom to thank.

user63872: Bitcoin is secured through proof-of-work mining using SHA256 as the mining algorithm. Bitcoin Cash uses the same algorithm, so the specialized ASIC hardware used to mine one coin, could also be used to mine the other. 
PoW coins are susceptible to ‘51% attacks’, which are possible when a bad actor controls a majority of the network’s hashpower. 
So generally, when considering ‘how secure’ a blockchain is, we consider how possible, or likely, it is for a single entity (or a group of colluding entities) to gain control of a majority of the hash power available for a coin. The more hashpower a coin has pointed at it, the more secure we can consider it to be. This is because an attacker would need a larger amount of hashpower under their control in order to enact an attack. 
From fork.lol, we can see that over the last 7 days, the BTC hashrate has been approx 47.3 exahashes/second, while the BCH hashrate has been approx 1.6 exahashes/second. 
By this measure, Bitcoin Cash is most certainly not ‘more secure’. 

93208: <p>I found in <a href="https://www.bitcoincash.org/index.html" rel="nofollow noreferrer">https://www.bitcoincash.org/index.html</a> that this technology is 
the world's most robust blockchain but searching for the details that explains why it is so secure I don't find any information. Some one knows a source that probes why this technology is secure and some technical information about the security implemented on it ?</p>
 7272: <p>As Nate mentioned, this is just a marketing statement. Any sane coin would try and promote themselves in this manner. Most are incorrect.</p>

<p>The most basic counter example being that many Bitcoin mining pools have enough hash power to perform a 51% attack on the Bitcoin cash chain. That alone is enough to not qualify it as the "World's most robust" chain.</p>
 38618: <p>I disagree with Chytrik: The hashrate and the number of miners are not the only factors that affect security. Here are some other factors:</p>

<ul>
<li>Frequency of code review of nodes/wallets</li>
<li>Reputation of the companies who create wallet</li>
<li>The number of nodes in the network</li>
<li>Formal verification of software</li>
<li>How well-documented the protocol is (in long term)</li>
<li>Frequency of breaking changes (and other changes)</li>
<li>Code readability and simplicity</li>
<li>Whether software is signed before signed</li>
</ul>

<p>Which means security is hard to measure.</p>

<p>If you had 1 BTC a year before, and today you open the wallet for the second time and that 1 BTC is still there, miners are not whom to thank.</p>
 63872: <p>Bitcoin is secured through proof-of-work mining using SHA256 as the mining algorithm. Bitcoin Cash uses the same algorithm, so the specialized ASIC hardware used to mine one coin, could also be used to mine the other. </p>

<p>PoW coins are susceptible to ‘<a href="https://bitcoin.stackexchange.com/q/658/63872">51% attacks</a>’, which are possible when a bad actor controls a majority of the network’s hashpower. </p>

<p>So generally, when considering ‘how secure’ a blockchain is, we consider how possible, or likely, it is for a single entity (or a group of colluding entities) to gain control of a majority of the hash power available for a coin. The more hashpower a coin has pointed at it, the more secure we can consider it to be. This is because an attacker would need a larger amount of hashpower under their control in order to enact an attack. </p>

<p>From <a href="https://fork.lol/pow/hashrate" rel="noreferrer">fork.lol</a>, we can see that over the last 7 days, the BTC hashrate has been approx 47.3 exahashes/second, while the BCH hashrate has been approx 1.6 exahashes/second. </p>

<p>By this measure, Bitcoin Cash is <strong>most certainly</strong> not ‘more secure’. </p>
