sodium_crypto_aead_chacha20poly1305_ietf_decrypt function mentions in its documentation that it'll always return a string. But when passed a malformed input as argument, it returns a boolean
(PHP 7 >= 7.2.0, PHP 8)
sodium_crypto_aead_chacha20poly1305_ietf_decrypt — Verify that the ciphertext includes a valid tag
$ciphertext,$additional_data,$nonce,$keyVerify then decrypt with ChaCha20-Poly1305 (IETF variant).
The IETF variant uses 96-bit nonces and 32-bit internal counters, instead of 64-bit for both.
ciphertextMust be in the format provided by sodium_crypto_aead_chacha20poly1305_ietf_encrypt() (ciphertext and tag, concatenated).
additional_dataAdditional, authenticated data. This is used in the verification of the authentication tag appended to the ciphertext, but it is not encrypted or stored in the ciphertext.
nonceA number that must be only used once, per message. 12 bytes long.
keyEncryption key (256-bit).
Returns the plaintext on success, or false on failure.
sodium_crypto_aead_chacha20poly1305_ietf_decrypt function mentions in its documentation that it'll always return a string. But when passed a malformed input as argument, it returns a boolean