What is the primary drawback to using advanced encryption standard (AES) algorithm with a 256 bit key to share sensitive data?

AES-256 is computationally efficient even at 256-bit key sizes; the larger key size does not meaningfully hinder encryption or decryption performance in modern implementations.

AES is natively supported by most modern operating systems, hardware, and messaging libraries, requiring no unusually complex configuration to use.

AES has not been proven weak; it remains unbroken and is trusted by NIST and security agencies worldwide for protecting classified information.

AES is a symmetric algorithm, meaning the identical 256-bit key must be shared with every intended recipient before they can decrypt the data. Securely transmitting this key to each recipient over an untrusted channel is the key distribution problem, and it typically requires an out-of-band channel or an asymmetric key exchange mechanism such as RSA or Diffie-Hellman. The more recipients involved, the more complex and risky the key distribution becomes.