S-63 is an International Hydrographic Organization (IHO) standard for

encrypting In cryptography, encryption (more specifically, encoding) is the process of transforming information in a way that, ideally, only authorized parties can decode. This process converts the original representation of the information, known as plain ...

, securing and compressing

electronic navigational chart An electronic navigational chart (ENC) is an official database created by a national hydrographic office for use with an Electronic Chart Display and Information System (ECDIS). ECDIS and ENCs are the primary means of electronic navigation on c ...

(ENC) data. The Data Protection Scheme was prepared by the IHO Data Protection Scheme Advisory Group, and was based on the protection scheme developed and operated by Primar as part of providing their protected ENC service. ECC (Electronic Chart Centre) and

United Kingdom Hydrographic Office The United Kingdom Hydrographic Office (UKHO) is the UK's agency for providing hydrographic and marine geospatial data to mariners and maritime organisations across the world. The UKHO is a trading fund of the Ministry of Defence (MoD) and is ...

were the original contributing organizations. The UKHO has since left this arrangement and Primar is now operated exclusively by ECC. The standard was adopted as the official IHO standard by the IHO member states in December 2002. The S-63 standard secures data by encrypting the basic transfer database using the

Blowfish Tetraodontidae is a family of marine and freshwater fish in the order Tetraodontiformes. The family includes many familiar species variously called pufferfish, puffers, balloonfish, blowfish, blowers, blowies, bubblefish, globefish, swellfish, ...

algorithm,

SHA-1 In cryptography, SHA-1 (Secure Hash Algorithm 1) is a hash function which takes an input and produces a 160-bit (20-byte) hash value known as a message digest – typically rendered as 40 hexadecimal digits. It was designed by the United States ...

- hashing the data based on a random key and adding a

CRC32 Computation of a cyclic redundancy check is derived from the mathematics of polynomial division, modulo two. In practice, it resembles long division of the binary message string, with a fixed number of zeroes appended, by the "generator poly ...

check. The standard also defines the systems to develop permit files that are delivered to end-users of ENC data enabling them to decrypt the data and use it for navigation. It also defines the use of DSA format signatures to authenticate the data originator, however because of poor implementation of the standard by

ECDIS An electronic navigational chart (ENC) is an official database created by a national hydrographic office for use with an Electronic Chart Display and Information System (ECDIS). ECDIS and ENCs are the primary means of electronic navigation on c ...

hardware manufacturers, virtually all signing is performed centrally by the

IHO The International Hydrographic Organization (IHO) (French: ''Organisation Hydrographique Internationale'') is an intergovernmental organization representing hydrography. the IHO comprised 102 member states. A principal aim of the IHO is to e ...

which acts as the scheme administrator. Exceptions to this are a few smaller resellers such as AUSRenc operated by AHS. Compression is achieved by applying the standard

ZIP (file format) ZIP is an archive file format that supports lossless compression, lossless data compression. A ZIP file may contain one or more files or directories that may have been compressed. The ZIP file format permits a number of Data compression, compr ...

algorithm to the base and update ENC files, before encryption. The other files are not compressed.

References

{{reflist Digital rights management Electronic navigation