”. how does a blockchain make sure that what you see is what i see without third party verification? first, data are recorded and shared in a way that ensures a consistent view across multiple parties. copies of the data are spread around all the nodes of the blockchain network. rather than trusting any single party, the trust is placed in the collective view of all parties. anybody can check whether something is wrong. second, data are heavily encrypted or signed with digital signatures that makes the blockchain secure against tampering. this means that all parties in the blockchain can be sure that no one can unilaterally make changes without the signature of the others. third, data are generated by smart contracts which always execute in the same expected way. the smart contract acts as an impartial judge. it executes contracts faithfully in accordance with the pre - defined contractual terms that all parties on the blockchain have agreed to. a blockchain is essentially a database that provides proof of who owns what at any given moment and an immutable record of all transactions. it is, in other words, a distributed ledger. distributed ledger technology, or dlt, has the potential to transform many industries and economic activities. this goes well beyond the original application of blockchains to bitcoins and cryptocurrencies. in fact, although crypto - currencies have attracted the most public attention, it is the broader applications of dlt that hold more promise over the short to medium term. industry applications of distributed ledger technology dlt is particularly suited for industry applications where it is important to know the histories of ownership but there is no trusted central party or reliance on the central party is inefficient or costly. take supply chain management for instance. dlt can provide the means for registering, certifying, and tracking the supply chain process at low cost. all goods will be uniquely identified and transferred through the distributed ledger, with each individual transaction verified, time - stamped, and encrypted in a transparent process. in financial services, dlt is being experimented with for a variety of applications. dlt may provide a more efficient alternative to credit bureaus that compile consumer credit information from banks. the insurance industry in singapore is looking at how dlt can help prevent duplicate insurance claims. 2 / 5 bis central bankers'speeches probably, one of the potentially more powerful applications in financial services is in

evolving views about the prospective standing of sovereign issuers ’ credit. with this in mind, let me turn now to the challenge of calibrating the size and duration of purchases that can deliver that yield constellation and, indirectly, the set of financing conditions consistent with our objective. for this, we rely on the current theory and empirics of quantitative interventions by central banks. the theory available today stipulates that it is primarily by announcing that the central bank will withdraw a certain stock of long - term bonds at a certain horizon, and thus a share of duration risk that otherwise would have to be borne by the market, that an asset purchase programme can impact on the term premium and on the yield curve in general. it is important to emphasise that it is the amount of duration that we extract relative to the amount of duration that otherwise would be in the market that produces the impact. in this respect, keeping the size of the app portfolio constant at a certain nominal level does not necessarily safeguard a given amount of accommodation. by keeping the portfolio of assets acquired under the app constant in nominal terms, it is difficult to prevent the ageing of the portfolio, i. e. its 4 / 6 bis central bankers'speeches gradual loss of duration as the securities held in the portfolio mature. although re - investments of the proceeds from principal payments of the maturing securities can, to a certain extent, offset this endogenous decay of the average portfolio duration – by replacing short - term expiring securities with the purchase of longer - term securities – this substitution effect is generally not strong enough to maintain the average maturity of the portfolio relative to that of the market portfolio at a level consistent with a given amount of accommodation. in addition, of course, the amount of duration that is supplied to the market by public and private issuers is not constant and indeed typically trends up. thus, keeping the central bank portfolio steady at a certain nominal level means that, in relative terms, the fraction of duration risk that is withdrawn from the market tends to fall. as time passes, the endogenous loss of duration in the central bank portfolio is bound to exert increasing upward pressure on the term premium. when the governing council will eventually judge that the transition to a sustained adjustment is likely to be completed within a medium term horizon with a sufficiently high degree of confidence, this endogenous process will act as a self - correction mechanism. in those conditions, the higher expected returns on business investment will make borrowing