Decentralized Identity in Practice: Benchmarking Latency, Cost, and Privacy
This paper presents an empirical benchmarking study comparing Ethereum, Hedera, and XRP Ledger across latency, cost, and privacy metrics, revealing distinct architectural trade-offs that guide the informed selection of Decentralized Identifier systems based on specific performance and privacy requirements.
Original paper licensed under CC BY 4.0 (http://creativecommons.org/licenses/by/4.0/). This is an AI-generated explanation of the paper below. It is not written or endorsed by the authors. For technical accuracy, refer to the original paper. Read full disclaimer
Imagine you are trying to build a digital ID card that belongs entirely to you, not to a government or a big corporation. This is called Decentralized Identity. Instead of storing your ID in a central database that could be hacked or tracked, you store it on a public, shared ledger (like a blockchain) where you control the keys.
But here's the problem: There are many different "blockchain neighborhoods" where you can build this ID. Some are fast, some are cheap, and some are very private. The authors of this paper wanted to answer a simple question: Which neighborhood is actually the best for building a digital ID, and what are the trade-offs?
They didn't just guess; they built a testing lab and ran three popular systems through a series of stress tests. Here is what they found, explained simply.
The Three Contenders
The researchers picked three different "blockchain cities" to test:
- Ethereum: The most famous, flexible city, but known for being expensive and sometimes slow.
- XRPL (XRP Ledger): A city known for being very predictable and having fixed, low prices.
- Hedera: A newer city known for being incredibly fast and efficient.
They tested three main actions for a digital ID:
- Create: Making a new ID.
- Update: Changing your keys or contact info.
- Resolve: Looking up someone else's ID to verify it.
The Race: Speed (Latency)
Think of Latency as the time it takes to send a letter and get a reply.
- Ethereum: Creating an ID here is like writing a letter on a piece of paper in your living room—it's instant! But, if you want to officially register that letter on the public record (on-chain), you have to wait for the town crier (the block) to come around. This takes about 12 seconds, and sometimes the line is long, making it take much longer.
- XRPL: This city runs on a strict schedule. You can't send a letter until the next scheduled bus arrives. It's not the absolute fastest, but it is extremely reliable. You know exactly when your letter will be delivered (about 5-6 seconds), every single time.
- Hedera: This city is like a high-speed train. Once the tracks are set up, the train moves incredibly fast (about 4 seconds). However, sometimes the train has to wait for a signal from a distant station (the mirror node), which can cause occasional, unpredictable delays.
The Surprise: The researchers found that the speed wasn't just about how fast the blockchain itself was. A huge chunk of the time was spent by the software tools (SDKs) doing the work before the letter even got to the blockchain. It's like the time you spend packing your suitcase before you even get to the airport.
The Price Tag (Cost)
Think of Cost as the postage stamp fee.
- Ethereum: The stamps are expensive. If you want to update your ID, it costs about $0.06. That's like paying for a fancy coffee every time you change your phone number.
- XRPL: The stamps are incredibly cheap and fixed. It costs about $0.00002 (a tiny fraction of a penny). It's like paying a flat fee for a postcard, no matter how busy the post office is.
- Hedera: Also very cheap, around $0.0001. It's slightly more than XRPL but still pennies.
The Surprise: Even though Ethereum and Hedera have totally different pricing systems, the extra cost to do a complex ID update compared to a simple money transfer was almost exactly the same (about 1.5 times more expensive). This suggests that the complexity of the ID update itself adds a standard "tax" regardless of the city you are in.
The Privacy Leak (Metadata)
This is the most interesting part. Think of Privacy as how much information is visible on the outside of your envelope. Even if the content of your letter is secret, the envelope (the metadata) might show your name, your address, and the time you sent it.
The researchers invented a score called the Metadata-Leakage Score (MLS) to measure how "fingerprintable" these envelopes are.
- XRPL: The envelopes are very verbose (wordy). They include a lot of extra details and standard fields. Because they are so wordy, they are easier to distinguish from one another, making it slightly easier for a snooper to link different actions to the same person.
- Hedera: The envelopes are lean and tight. They strip away unnecessary details. Even though the specific fields might vary a bit, the overall "shape" of the envelope is so uniform that it's harder to tell one person's actions from another's. Hedera had the lowest privacy leakage.
- Ethereum: It sits in the middle.
The Big Takeaway
The paper concludes that there is no single "perfect" city. It depends on what you value most:
- Choose Hedera if: You need speed and care about privacy. It's the best for things that happen quickly and often, like updating keys frequently.
- Choose XRPL if: You need predictability and the lowest possible cost. It's great for large-scale systems where you need to know exactly what the bill will be, even if the data is slightly more "wordy."
- Choose Ethereum if: You need to connect with the massive existing world of other apps and tools (ecosystem), even if it costs more and takes longer.
The Final Lesson:
The researchers realized that when we talk about "blockchain speed," we often forget the software tools we use to talk to the blockchain. The "software overhead" (packing the suitcase) is just as important as the "blockchain speed" (the train ride). To build a better digital ID system, we need to fix both the train and the suitcase.
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