Cnv class¶

class cryptosyspki.Cnv¶

Character conversion routines.

class EndianNess¶

Byte order for integer/byte array conversions.

BIG_ENDIAN = 0¶: Big-endian order (default)

LITTLE_ENDIAN = 1¶: Little-endian order

static frombase58(s)¶

Decode a base58-encoded string into a byte array.

Uses the "Bitcoin" scheme of base58 encoding where the leading character '1' is reserved for representing an entire leading zero byte.

Parameters:: s (str) -- Base58-encoded data
Returns:: Binary data in byte array.
Return type:: bytes

static frombase64(s)¶

Decode a base64-encoded string into a byte array.

Parameters:: s (str) -- Base64-encoded data
Returns:: Binary data in byte array.
Return type:: bytes

Remarks:: Whitespace characters are ignored, but other non-base64 characters will cause an error.

static fromhex(s)¶

Decode a hexadecimal-encoded string into a byte array.

Parameters:: s (str) -- Hex-encoded string
Returns:: Binary data in byte array.
Return type:: bytes

Note

Whitespace and ASCII punctuation characters in the input are ignored, but other non-hex characters, e.g. [G-Zg-z], will cause an error.

Examples

>>> Cnv.fromhex("61:62:63")
'abc'

static num_from_bytes(data, endn=EndianNess.BIG_ENDIAN)¶

Convert the leftmost four bytes of an array to a 32-bit integer.

An array shorter than 4 bytes will be padded on the right with zeros.

Parameters:

data (bytes) -- Byte array to be converted
endn (EndianNess) -- Byte order

Returns:

Integer value.

Return type:

int

Examples

>>> hex(Cnv.num_from_bytes(Cnv.fromhex("DEADBEEF")))
'0xdeadbeefL'
>>> hex(Cnv.num_from_bytes(Cnv.fromhex("DEADBEEF"), Cnv.EndianNess.LITTLE_ENDIAN))
'0xefbeaddeL'

static num_to_bytes(num, endn=EndianNess.BIG_ENDIAN)¶

Convert a 32-bit integer to an array of 4 bytes.

Parameters:

num (int) -- Integer to be converted
endn (EndianNess) -- Byte order

Returns:

Byte array containing representation of integer in given order.

Return type:

bytes

static reverse_bytes(data)¶

Reverse the order of a byte array.

Parameters:: data (bytes) -- Input data to be reversed
Returns:: Byte array in reverse order.
Return type:: bytes

Examples

>>> Cnv.tohex(Cnv.reverse_bytes(Cnv.fromhex("DEADBEEF01")))
'01EFBEADDE'

static shortpathname(pathName)¶

Retrieve the Windows short path form of the specified path.

Parameters:: pathName (str) -- Path name.
Returns:: Windows short path name of file or empty string if file does not exist.
Return type:: str

Remarks:: Windows only. The file path must exist. The short path name is guaranteed to be ASCII and can be used as a filename argument in any function in this Toolkit.

Example

>>> Cnv.shortpathname("work/你好.txt")
'work/FC0F~1.TXT'

static tobase58(data)¶

Encode binary data as a base58 string.

Uses the "Bitcoin" scheme of base58 encoding where the leading character '1' is reserved for representing an entire leading zero byte.

Parameters:: data (bytes) -- binary data
Returns:: Base58-encoded string.
Return type:: str

Example

>>> Cnv.tobase58(Cnv.fromhex("00010966776006953D5567439E5E39F86A0D273BEED61967F6"))
'16UwLL9Risc3QfPqBUvKofHmBQ7wMtjvM'

static tobase64(data)¶

Encode binary data as a base64 string.

Parameters:: data (bytes) -- binary data to be encoded.
Returns:: Base64-encoded string.
Return type:: str

Example

>>> Cnv.tobase64(Cnv.fromhex('fedcba9876543210'))
'/ty6mHZUMhA='

static tohex(data)¶

Encode binary data as a hexadecimal string.

Parameters:: data (bytes) -- binary data to be encoded.
Returns:: Hex-encoded string. Letters [A-F] are in uppercase. Use s.lower() for lowercase.
Return type:: str

Examples

>>> Cnv.tohex(b"abcé")
'616263E9'
>>> Cnv.tohex(bytearray([0xde, 0xad, 0xbe, 0xef])).lower()
'deadbeef'

static utf8_check(data)¶

Check if a byte array or string contains valid UTF-8 characters. Returns integer code.

Parameters:

data (bytes) -- input byte array to check

Returns:

Integer code indicating nature of encoded characters:

0 -- Not valid UTF-8
1 -- Valid UTF-8, all characters are 7-bit ASCII
2 -- Valid UTF-8, contains at least one multi-byte character equivalent to 8-bit ANSI
3 -- Valid UTF-8, contains at least one multi-byte character that cannot be represented in a single-byte character set

Return type:

int

static utf8_check_file(filename)¶

Check if a file contains valid UTF-8 characters. Returns integer code.

Parameters:

filename (str) -- name of file to check

Returns:

Integer code indicating nature of encoded characters:

0 -- Not valid UTF-8
1 -- Valid UTF-8, all characters are 7-bit ASCII
2 -- Valid UTF-8, contains at least one multi-byte character equivalent to 8-bit ANSI
3 -- Valid UTF-8, contains at least one multi-byte character that cannot be represented in a single-byte character set

Return type:

int

static utf8_check_to_string(n)¶

Return a string describing an integer code returned by Cnv.utf8_check() and Cnv.utf8_check_file().

Examples

>>> Cnv.utf8_check_to_string(Cnv.utf8_check("abc".encode()))
'Valid UTF-8, all characters are 7-bit ASCII'