A data processing system is provided that includes applications, databases, encryption engines, and decryption engines. Encryption and decryption engines may be used to perform format-preserving encryption on data strings stored in a database. Encryption and decryption engines may include embedded-format-preserving encryption and decryption engines. Embedded-format-preserving encryption engines may be used to encrypt data strings and embed information in data strings. Information corresponding to a format-preserving encryption operation of a data string may be embedded in an associated data string. The associated data string may be encrypted before or after embedding the information in the associated data string. The embedded information may include key management data that corresponds to a managed encryption key that was used to encrypt the data string.