【国外标准】 Financial Services - Symmetric Key Cryptography for the Financial Services Industry - Format-Preserving Encryption - Part 1: Definition and Model/Part 2: Key Stream with Counter Mode

X9.124 Symmetric Key Cryptography for the Financial Services Industry Format Preserving Encryption is a suite of standards consisting of five parts. Part 1 of this standard includes a set of definitions common to all FPE techniques, a security model for FPE block cipher techniques, and a description of the pseudocode language used in defining the mode specified in this document. Part 2 defines requirements for Format Preserving Encryption - Counter Mode (FPCM). FPCM methods encrypt data strings of a specific length and character set into ciphertext of the same length using the same character set and using the equivalent of Counter Mode (CTR) defined in NIST SP38B. Format Preserving Encryption is useful in situations where fixed-format data, such as Primary Account Numbers (PANs) or Social Security Numbers, must be encrypted, but there is a requirement to limit changes to existing communication protocols, database schemata or application code. FPCM is a particularly simple and efficient mechanism to achieve format preserving encryption, which shares many of the strengths and challenges of CTR.