Python Modules

The legacryptor package is an implementation to handle the GA4GH cryptographic file format.

legacryptor.cli	LocalEGA utilities for the cryptographic GA4GH standard.
legacryptor.crypt4gh	Crypt4GH Encryption/Decryption
legacryptor.pubring	Pubring operations.
legacryptor.exceptions	Exceptions

Command Line

LocalEGA utilities for the cryptographic GA4GH standard.

Usage:

lega-cryptor [-hv] [–log <file>] list [-s <URL> | -p <path>] lega-cryptor [-hv] [–log <file>] encrypt [-r <recipient>] -s <URL> [-i <input>] [-o <output>] lega-cryptor [-hv] [–log <file>] encrypt [-r <recipient>] [-p <path>] [-i <input>] [-o <output>] lega-cryptor [-hv] [–log <file>] encrypt –pk <path> [-i <input>] [-o <output>] lega-cryptor [-hv] [–log <file>] decrypt –sk <path> [-i <input>] [-o <output>] lega-cryptor [-hv] [–log <file>] reencrypt –sk <path> –pk <path> [-i <input>] [-o <output>] lega-cryptor [-hv] [–log <file>] reencrypt –server <url> –keyid <secret> [-i <input>] [-o <output>]

Options:

-h, --help	Prints this help and exit
-v, --version	Prints the version and exits
--log <file>	Path to the logger file (in YML format)
-s <URL>, --server <URL>
	Lists information about all keys in the keyserver
-p <file>, --pubring <file>
	Lists information about all keys in the pubring. If not specified, a default pubring is used either from the LEGA_PUBRING environment variable (if it exists) or as the one supplied within this package.
-r RECIPIENT	Encrypt for the given recipient [default: ega@crg.eu]
--pk <keyfile>	Public PGP key to be used for encryption
--sk <keyfile>	Private PGP key to be used for decryption
--keyid <id>	Key ID used to retrieve the key material from the keyserver
-i <file>, --input <file>
	Input file. If not specified, it uses stdin
-o <file>, --output <file>
	Output file. If not specified, it uses stdout

Environment variables:

LEGA_LOG If defined, it will be used as the default logger LEGA_PUBRING If defined, it will be used as the default pubring

Crypt4gh

Crypt4GH Encryption/Decryption

class legacryptor.crypt4gh.Header

A header is composed of unencrypted part and an encrypted part. The unencrypted part is ‘crypt4gh’ + 4 bytes for the version + the length of the encrypted and unencrypted parts. The encrypted part is:

• 4 bytes for the number <n> of files contained in the encrypted part

• <n> record, where a record is:

  • 8 bytes for the plaintext_start
  • 8 bytes for the plaintext_end
  • 8 bytes for the ciphertext_start
  • 8 bytes for the counter_offset (in case several files are concatenated)

• then

  • 4 bytes for the method: here only 0 (for AES-256-CTR).
  • 32 bytes for the session key
  • 16 bytes for the IV

legacryptor.crypt4gh.encrypt(pubkey, infile, infilesize, outfile, chunk_size=4096)

Encrypt.

legacryptor.crypt4gh.get_header(infile)

Extract header and advance file position to AES block.

legacryptor.crypt4gh.decrypt(privkey, infile, process_output=<function do_nothing>, chunk_size=4096)

Decrypt.

legacryptor.crypt4gh.reencrypt(pubkey, privkey, infile, process_output=<function do_nothing>, chunk_size=4096)

Extract header and update with another one The AES encrypted part is only copied

legacryptor.crypt4gh.get_key_id(header)

Retrieve KeyID.

legacryptor.crypt4gh.header_to_records(privkey, header, passphrase)

Extracting header from record.

Pubring

Pubring operations.

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