The History and Evolution of 21 Analytics’ AOPP

As the Travel Rule expands globally, proving self-hosted wallet ownership has become a must in many regions. This prerequisite has posed an issue for crypto asset service providers (CASPs), as the available verification methods are slow, costly, and unreliable. For customers, it has resulted in a cumbersome user experience, leaving both parties frustrated. 

21 Analytics recognised these issues from the onset and developed AOPP to address these challenges for CASPs and their customers. Since its inception, AOPP has evolved into the leading self-hosted wallet verification method. 

Cited by regulators, trusted by compliance teams, and favoured by customers, we explain the history of AOPP, how it overcame industry challenges, and how it can benefit CASPs below. 

The History of AOPP 

In 2019, Switzerland was one of the first countries to implement the Travel Rule, with self-hosted wallets falling under its scope. At this time, proving wallet ownership was an unfamiliar concept to most wallet users, with the available methods being cumbersome, expensive or unreliable from a CASP’s perspective. 

As avid Bitcoiners, we understood that this new requirement would add friction to the user experience, which prompted us to develop AOPP. AOPP was designed to provide a straightforward method for users to prove wallet ownership and a reliable and trustworthy proof for CASPs to ensure Travel Rule compliance. 

“When Switzerland first enforced the Travel Rule, we realised that proving wallet ownership would become a major usability challenge for both CASPs and customers. We built AOPP to make this process as seamless and privacy-preserving as possible, staying true to Bitcoin’s values while ensuring compliance.” 

Lucas Betschart, COO & Co-Founder, 21 Analytics.

In 2023, enhancements were made to further streamline the signing process for both users and CASPs, boosting compatibility with even more wallets. 

The launch of the AOPP Portal in 2024 marked a significant milestone for 21 Analytics. With its launch, AOPP was now compatible with more than 400 wallets, 2400 digital assets, and over 50 blockchains, including Solana and TRON. Additionally, we simplified the signing process even further for wallet owners. 

However, our team didn’t stop there. In 2025, we added further features; for example, BitBox wallet users can now select their wallet addresses for proofs. But most notably, is the even broader wallet support with TronLink and Phantom joining the AOPP family. Today, the AOPP Portal supports over 540 wallets and more than 2800 digital assets.

AOPP Overcomes the Backlash 

In 2020, when AOPP was developed, it was met with backlash from the conservative crypto community. Due to the novelty of the Travel Rule at the time and its requirement to prove self-hosted wallet ownership, many users believed this wallet proof mechanism infringed on their privacy. While not accurate then or now, it was a predictable reaction due to the limited knowledge on the topic, as very few jurisdictions, except for Switzerland, had imposed this requirement. 

Moreover, competitors also attacked AOPP in an attempt to undermine it, spreading misinformation. 

However, this did not deter 21 Analytics, as we knew we had a solution that would ensure Travel Rule compliance for CASPs and aid wallet users in the proof-of-ownership process.

AOPP Present Day

Because AOPP is not jurisdiction-specific, it has become an industry favourite for proving self-hosted wallet ownership among regulators and compliance teams alike. The British Virgin Island Financial Services Commission has cited it as a preferred method for self-hosted wallet proofs, with many jurisdictions following suit. 

Additionally, compliance expert Delphine Forma has stated that “AOPP could solve the cumbersome proof of ownership issue.”

To date, AOPP Portal supports over 540 wallets, including Ledger, Trezor, MetaMask, Phantom, TronLink, BitBox, and many more, the biggest blockchains like Bitcoin, Ethereum, Binance Chain, Solana, TRON, and Polygon and over 2800 digital assets, with these numbers continuously growing. 

How AOPP Works 

In essence, AOPP is a straightforward technology, and it was intentionally designed in this manner. 

A self-hosted wallet holder will access their exchange and request a withdrawal from their wallet. Based on this prompt, they will be directed to the AOPP Portal. Within the portal, they follow a few quick and easy instructions to complete the ownership process. Upon completing the process, their proof is automatically sent to their exchange, and they can then proceed with the transaction. 

For wallet users, this process takes a matter of seconds. Even first-time users have reported how “unbelievably easy” the signing process is when compared to other methods, such as the Satoshi Test.  

On the CASP’s side, the whole process is automated. All they need to do is wait for their customer to complete the process. No manual review is required: As soon as the customer completes the process, the proof appears in their Travel Rule compliance software within seconds. 

How AOPP Can Help CASPs 

AOPP is not just a tool designed to simplify the wallet verification process for CASP customers; it is a game-changer for CASPs in many ways. For starters, once integrated via the 21 Analytics API, the wallet verification process is completely automated for CASPs. No manual reviews, no verifications, or other requirements are necessary from the compliance team. A CASP customer will request a withdrawal from their wallet, complete the verification process using the link automatically provided to them. Upon successful completion of the verification process, the proof will automatically appear in the Travel Rule solution’s dashboard. 

Additionally, the proof process can be done in seconds. Due to its swiftness, AOPP withdrawals can be processed much faster than Satoshi Test proofs, which can be affected by blockchain speeds, and visual proofs, which need a manual review from the compliance team. Speedier transactions mean happier customers. 

The integration mentioned above is quick and easy; it can be done in less than 10 lines of code, and it saves time and money on having to develop an in-house solution.  

“[AOPP] was really easy to implement and offered a great and simple user experience for the end customers”,

Simon Kirnberger, Product Owner Digital Asset Custody at Tangany.

Finally, AOPP is reliable. Because AOPP is a cryptographic signature, compliance teams can be assured that the proofs received are accurate and cannot be tampered with, guaranteeing Travel Rule compliance. 

Find out more about AOPP by seeing it in action. Request a demo today.