As a professional, I must begin by saying that the topic of a registered sale agreement for Aadhaar card is not only uncommon but also not legally possible. Aadhaar is a unique identity number that is issued by the Indian government to its citizens. It is used as a means of identification for various purposes such as opening bank accounts, applying for loans, getting a new passport, and so on.

However, the question that arises is whether it is possible to sell or transfer the Aadhaar card to someone else. The answer is NO. The Aadhaar card is not transferable or tradeable, and it cannot be sold or bought by any means. The reason behind this is that the Aadhaar number is linked to the biometric data of the individual, which is unique and cannot be replicated.

Moreover, any transaction related to the sale or purchase of the Aadhaar card would be illegal and would attract severe legal consequences. The Indian government has enforced strict laws to prevent any kind of fraud or misuse of the Aadhaar card. Therefore, any attempt to sell or transfer the Aadhaar card would be considered a violation of the law.

It is also worth noting that the Aadhaar card cannot be used as a means of authentication for executing a registered sale agreement. A registered sale agreement is a legal document that records the transfer of ownership of a property from the seller to the buyer. It requires the registration of the property with the appropriate authority, and the execution of the sale agreement has to be done in the presence of witnesses.

In conclusion, it is important to understand that the Aadhaar card is a unique identity number that is strictly non-transferable and cannot be sold or bought. The Indian government has implemented strict laws to prevent any kind of fraud or misuse of the Aadhaar card. Therefore, there is no question of a registered sale agreement for Aadhaar card as such an agreement would be illegal and attract severe legal consequences.