Electronic Transactions Act (Cap. 88): Governs electronic transactions, including requirements for electronic signatures, legal recognition of electronic records, and validity of electronic execution of documents

Contract Act (Cap. 53): Fundamental law governing contract formation, including elements of valid contracts, capacity to authorize, and clear expression of intent in contractual relationships

Evidence Act (Cap. 97): Regulates requirements for documentary evidence and the admissibility of authorization letters in legal proceedings

Personal Data Protection Act 2012: Governs the collection, use, and disclosure of personal data, including consent requirements and purpose limitation principles

Stamps Act (Cap. 312): Determines whether stamp duty applies to specific types of authorization documents

Common Law Principles - Agency: Established legal principles governing agency relationships, including scope of authority and responsibilities between principal and agent

Industry-Specific Regulations: Additional regulations that may apply depending on the specific purpose of the authorization (financial, medical, legal, etc.)