ENCODER::asn::asnSequenceevalue...
Takes zero or more encoded values, packs them into an ASN sequence and returns its encoded binary
form.
::asn::asnSequenceFromListelist
Takes a list of encoded values, packs them into an ASN sequence and returns its encoded binary
form.
::asn::asnSetevalue...
Takes zero or more encoded values, packs them into an ASN set and returns its encoded binary form.
::asn::asnSetFromListelist
Takes a list of encoded values, packs them into an ASN set and returns its encoded binary form.
::asn::asnApplicationConstrappNumberevalue...
Takes zero or more encoded values, packs them into an ASN application construct and returns its
encoded binary form.
::asn::asnApplicationappNumberdata
Takes a single encoded value data, packs it into an ASN application construct and returns its
encoded binary form.
::asn::asnChoiceappNumberevalue...
Takes zero or more encoded values, packs them into an ASN choice construct and returns its encoded
binary form.
::asn::asnChoiceConstrappNumberevalue...
Takes zero or more encoded values, packs them into an ASN choice construct and returns its encoded
binary form.
::asn::asnIntegernumber
Returns the encoded form of the specified integer number.
::asn::asnEnumerationnumber
Returns the encoded form of the specified enumeration id number.
::asn::asnBooleanbool
Returns the encoded form of the specified boolean value bool.
::asn::asnContextcontextdata
Takes an encoded value and packs it into a constructed value with application tag, the context
number.
::asn::asnContextConstrcontextevalue...
Takes zero or more encoded values and packs them into a constructed value with application tag,
the context number.
::asn::asnObjectIdentifieridlist
Takes a list of at least 2 integers describing an object identifier (OID) value, and returns the
encoded value.
::asn::asnUTCTimeutcstring
Returns the encoded form of the specified UTC time string.
::asn::asnNull
Returns the NULL encoding.
::asn::asnBitStringstring
Returns the encoded form of the specified string.
::asn::asnOctetStringstring
Returns the encoded form of the specified string.
::asn::asnNumericStringstring
Returns the string encoded as ASN.1 NumericString. Raises an error if the string contains
characters other than decimal numbers and space.
::asn::asnPrintableStringstring
Returns the string encoding as ASN.1 PrintableString. Raises an error if the string contains
characters which are not allowed by the Printable String datatype. The allowed characters are A-Z,
a-z, 0-9, space, apostrophe, colon, parentheses, plus, minus, comma, period, forward slash,
question mark, and the equals sign.
::asn::asnIA5Stringstring
Returns the string encoded as ASN.1 IA5String. Raises an error if the string contains any
characters outside of the US-ASCII range.
::asn::asnBMPStringstring
Returns the string encoded as ASN.1 Basic Multilingual Plane string (Which is essentialy big-
endian UCS2).
::asn::asnUTF8Stringstring
Returns the string encoded as UTF8 String. Note that some legacy applications such as Windows
CryptoAPI do not like UTF8 strings. Use BMPStrings if you are not sure.
::asn::asnStringstring
Returns an encoded form of string, choosing the most restricted ASN.1 string type possible. If the
string contains non-ASCII characters, then there is more than one string type which can be used.
See ::asn::defaultStringType.
::asn::defaultStringType ?type?
Selects the string type to use for the encoding of non-ASCII strings. Returns current default when
called without argument. If the argument type is supplied, it should be either UTF8 or BMP to
choose UTF8String or BMPString respectively.
DECODER
General notes:
[1] Nearly all decoder commands take two arguments. These arguments are variable names, except for
::asn::asnGetResponse. The first variable contains the encoded ASN value to decode at the
beginning, and more, and the second variable is where the value is stored to. The remainder of the
input after the decoded value is stored back into the datavariable.
[2] After extraction the data variable is always modified first, before by writing the extracted value
to its variable. This means that if both arguments refer to the same variable, it will always
contain the extracted value after the call, and not the remainder of the input.
::asn::asnPeekBytedata_varbyte_var
Retrieve the first byte of the data, without modifing data_var. This can be used to check for
implicit tags.
::asn::asnGetLengthdata_varlength_var
Decode the length information for a block of BER data. The tag has already to be removed from the
data.
::asn::asnGetResponsechandata_var
Reads an encoded ASN sequence from the channel chan and stores it into the variable named by
data_var.
::asn::asnGetIntegerdata_varint_var
Assumes that an encoded integer value is at the front of the data stored in the variable named
data_var, extracts and stores it into the variable named by int_var. Additionally removes all
bytes associated with the value from the data for further processing by the following decoder
commands.
::asn::asnGetEnumerationdata_varenum_var
Assumes that an enumeration id is at the front of the data stored in the variable named data_var,
and stores it into the variable named by enum_var. Additionally removes all bytes associated with
the value from the data for further processing by the following decoder commands.
::asn::asnGetOctetStringdata_varstring_var
Assumes that a string is at the front of the data stored in the variable named data_var, and
stores it into the variable named by string_var. Additionally removes all bytes associated with
the value from the data for further processing by the following decoder commands.
::asn::asnGetStringdata_varstring_var ?type_var?
Decodes a user-readable string. This is a convenience function which is able to automatically
distinguish all supported ASN.1 string types and convert the input value appropriately. See
::asn::asnGetPrintableString, ::asnGetIA5String, etc. below for the type-specific conversion
commands.
If the optional third argument type_var is supplied, then the type of the incoming string is
stored in the variable named by it.
The function throws the error "Invalid command name asnGetSomeUnsupportedString" if the
unsupported string type Unsupported is encountered. You can create the appropriate function
"asn::asnGetSomeUnsupportedString" in your application if neccessary.
::asn::asnGetNumericStringdata_varstring_var
Assumes that a numeric string value is at the front of the data stored in the variable named
data_var, and stores it into the variable named by string_var. Additionally removes all bytes
associated with the value from the data for further processing by the following decoder commands.
::asn::asnGetPrintableStringdata_varstring_var
Assumes that a printable string value is at the front of the data stored in the variable named
data_var, and stores it into the variable named by string_var. Additionally removes all bytes
associated with the value from the data for further processing by the following decoder commands.
::asn::asnGetIA5Stringdata_varstring_var
Assumes that a IA5 (ASCII) string value is at the front of the data stored in the variable named
data_var, and stores it into the variable named by string_var. Additionally removes all bytes
associated with the value from the data for further processing by the following decoder commands.
::asn::asnGetBMPStringdata_varstring_var
Assumes that a BMP (two-byte unicode) string value is at the front of the data stored in the
variable named data_var, and stores it into the variable named by string_var, converting it into a
proper Tcl string. Additionally removes all bytes associated with the value from the data for
further processing by the following decoder commands.
::asn::asnGetUTF8Stringdata_varstring_var
Assumes that a UTF8 string value is at the front of the data stored in the variable named
data_var, and stores it into the variable named by string_var, converting it into a proper Tcl
string. Additionally removes all bytes associated with the value from the data for further
processing by the following decoder commands.
::asn::asnGetUTCTimedata_varutc_var
Assumes that a UTC time value is at the front of the data stored in the variable named data_var,
and stores it into the variable named by utc_var. The UTC time value is stored as a string, which
has to be decoded with the usual clock scan commands. Additionally removes all bytes associated
with the value from the data for further processing by the following decoder commands.
::asn::asnGetBitStringdata_varbits_var
Assumes that a bit string value is at the front of the data stored in the variable named data_var,
and stores it into the variable named by bits_var as a string containing only 0 and 1.
Additionally removes all bytes associated with the value from the data for further processing by
the following decoder commands.
::asn::asnGetObjectIdentifierdata_varoid_var
Assumes that a object identifier (OID) value is at the front of the data stored in the variable
named data_var, and stores it into the variable named by oid_var as a list of integers.
Additionally removes all bytes associated with the value from the data for further processing by
the following decoder commands.
::asn::asnGetBooleandata_varbool_var
Assumes that a boolean value is at the front of the data stored in the variable named data_var,
and stores it into the variable named by bool_var. Additionally removes all bytes associated with
the value from the data for further processing by the following decoder commands.
::asn::asnGetNulldata_var
Assumes that a NULL value is at the front of the data stored in the variable named data_var and
removes the bytes used to encode it from the data.
::asn::asnGetSequencedata_varsequence_var
Assumes that an ASN sequence is at the front of the data stored in the variable named data_var,
and stores it into the variable named by sequence_var. Additionally removes all bytes associated
with the value from the data for further processing by the following decoder commands.
The data in sequence_var is encoded binary and has to be further decoded according to the
definition of the sequence, using the decoder commands here.
::asn::asnGetSetdata_varset_var
Assumes that an ASN set is at the front of the data stored in the variable named data_var, and
stores it into the variable named by set_var. Additionally removes all bytes associated with the
value from the data for further processing by the following decoder commands.
The data in set_var is encoded binary and has to be further decoded according to the definition of
the set, using the decoder commands here.
::asn::asnGetApplicationdata_varappNumber_var ?content_var? ?encodingType_var?
Assumes that an ASN application construct is at the front of the data stored in the variable named
data_var, and stores its id into the variable named by appNumber_var. Additionally removes all
bytes associated with the value from the data for further processing by the following decoder
commands. If a content_var is specified, then the command places all data associated with it into
the named variable, in the binary form which can be processed using the decoder commands of this
package. If a encodingType_var is specified, then that var is set to 1 if the encoding is
constructed and 0 if it is primitive.
Otherwise it is the responsibility of the caller to decode the remainder of the application
construct based on the id retrieved by this command, using the decoder commands of this package.
::asn::asnGetContextdata_varcontextNumber_var ?content_var? ?encodingType_var?
Assumes that an ASN context tag construct is at the front of the data stored in the variable named
data_var, and stores its id into the variable named by contextNumber_var. Additionally removes all
bytes associated with the value from the data for further processing by the following decoder
commands. If a content_var is specified, then the command places all data associated with it into
the named variable, in the binary form which can be processed using the decoder commands of this
package. If a encodingType_var is specified, then that var is set to 1 if the encoding is
constructed and 0 if it is primitive.
Otherwise it is the responsibility of the caller to decode the remainder of the construct based on
the id retrieved by this command, using the decoder commands of this package.
HANDLINGTAGS
Working with ASN.1 you often need to decode tagged values, which use a tag thats different from the
universal tag for a type. In those cases you have to replace the tag with the universal tag used for the
type, to decode the value. To decode a tagged value use the ::asn::asnRetag to change the tag to the
appropriate type to use one of the decoders for primitive values. To help with this the module contains
three functions:
::asn::asnPeekTagdata_vartag_vartagtype_varconstr_var
The ::asn::asnPeekTag command can be used to take a peek at the data and decode the tag value,
without removing it from the data. The tag_var gets set to the tag number, while the tagtype_var
gets set to the class of the tag. (Either UNIVERSAL, CONTEXT, APPLICATION or PRIVATE). The
constr_var is set to 1 if the tag is for a constructed value, and to 0 for not constructed. It
returns the length of the tag.
::asn::asnTagtagnumber ?class? ?tagstyle?
The ::asn::asnTag can be used to create a tag value. The tagnumber gives the number of the tag,
while the class gives one of the classes (UNIVERSAL,CONTEXT,APPLICATION or PRIVATE). The class may
be abbreviated to just the first letter (U,C,A,P), default is UNIVERSAL. The tagstyle is either C
for Constructed encoding, or P for primitve encoding. It defaults to P. You can also use 1 instead
of C and 0 instead of P for direct use of the values returned by ::asn::asnPeekTag.
::asn::asnRetagdata_varnewTag
Replaces the tag in front of the data in data_var with newTag. The new Tag can be created using
the ::asn::asnTag command.
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