How Can I solve this Error:

i am using encrypt package to encrypt and decrypt my plaintext. i have followed the examples in https://pub.dev/packages/encrypt. it encrypts and decrypts successfully until i hot restart my app. after i hot restart, the it returns the following error: Invalid or corrupted pad block. the plaintext are encrypted and uploaded to Firestore and for decryption, it is retrieved from Firestore and decrypted. tia for all inputs