Abstract: A pointer is set to a first code unit of an original string that encodes characters via code units within an encoding scheme. Whether the code unit of the original string referenced by the pointer is valid within the encoding scheme is determined. If the code unit referenced by the pointer is valid, one or more code units of the original string that encode a single character within the encoding scheme are processed, starting at the code unit referenced by the pointer. The one or more code units as have been processed are appended to a processed string. A single shadow unit indicating that the one or more code units that have been processed are valid is appended to a shadow array. The pointer is advanced to the code unit of the original string following the one or more code units.

Abstract: Techniques for Precision-Preserving Format-Preserving Encryption (PPFPE) to protect numeric values and strings with leading/trailing and special characters, while preserving their precision, both as a protected value (e.g., ciphertext) and when decrypted are provided. In one aspect, a plaintext string is parsed to detect a first and last sentinel characters, wherein any character(s) preceding the first sentinel character comprises a leading character(s) and any character(s) following the last sentinel character comprises a trailing character(s). Any leading character(s) preceding the first sentinel character and/or any trailing character(s) following the last sentinel character are passed through. A ciphertext string is generated by encrypting the first and last sentinel character using one or more subsets of a set of encryption characters; and encrypting the portion of the plaintext string between the first and last sentinel character using the set of encryption characters.