PQ-single-address-backup - BIP-38 for P2MR (bc1z) - 104-char encrypted backup format

The recent update to the paper backup system has incorporated significant enhancements to ensure data integrity and security. The feedback provided highlighted the necessity of more than just a fixed length for reliability; as such, typo checks have been implemented. The upgraded system now utilizes a fixed length of 108 characters in Base58 encoding, which translates to 79 bytes, an increase from the previous 76 bytes.

This adjustment includes the addition of a two-byte CRC16 checksum in the header, which is verified before any Key Derivation Function (KDF) processes occur. The structure of the backup is meticulously designed with distinct components: one byte for versioning, two bytes dedicated to the CRC16 (covering salt, initialization vector, and ciphertext), followed by 16 bytes of salt, 12 bytes for the initialization vector, and 48 bytes designated for the ciphertext. This structured approach not only simplifies auditing but also boosts confidence in data recovery procedures.