Unit ASN.1
From Ultibo.org
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Description
Ultibo ASN.1 Interface unit
Abstract Syntax Notation One (ASN.1) is an interface description language for defining data structures that can be serialized and deserialized in a standard, cross-platform way. It's broadly used in telecommunications and computer networking, and especially in cryptography.
This unit currently only provides the basic functionality required by X509 to read and parse a certificate in DER format.
It is expected that this unit will be expanded to incorporate additional functions over time.
Constants
ASN1 specific constants
ASN1_* ASN1_TAG_EOC = $00;
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Not used with DER |
ASN1_TAG_BOOLEAN = $01;
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ASN1_TAG_INTEGER = $02;
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ASN1_TAG_BITSTRING = $03;
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ASN1_TAG_OCTETSTRING = $04;
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ASN1_TAG_NULL = $05;
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ASN1_TAG_OID = $06;
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ASN1_TAG_OBJECT_DESCRIPTOR = $07;
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Not supported |
ASN1_TAG_EXTERNAL = $08;
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Not supported |
ASN1_TAG_REAL = $09;
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Not supported |
ASN1_TAG_ENUMERATED = $0A;
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Not supported |
ASN1_TAG_EMBEDDED_PDV = $0B;
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Not supported |
ASN1_TAG_UTF8STRING = $0C;
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Not supported |
ANS1_TAG_RELATIVE_OID = $0D;
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ASN1_TAG_SEQUENCE = $10;
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Constructed |
ASN1_TAG_SET = $11;
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ASN1_TAG_NUMERICSTRING = $12;
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Not supported |
ASN1_TAG_PRINTABLESTRING = $13;
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ASN1_TAG_TG1STRING = $14;
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Not supported |
ASN1_TAG_VIDEOTEXSTRING = $15;
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Not supported |
ASN1_TAG_IA5STRING = $16;
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ASN1_TAG_UTCTIME = $17;
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ASN1_TAG_GENERALIZEDTIME = $18;
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Not supported |
ASN1_TAG_GRAPHICSTRING = $19;
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Not supported |
ASN1_TAG_VISIBLESTRING = $1A;
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ASN1_TAG_GENERALSTRING = $1B;
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Not supported |
ASN1_TAG_UNIVERSALSTRING = $1C;
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Not supported |
ASN1_TAG_CHARACTERSTRING = $1D;
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Not supported |
ASN1_TAG_BMPSTRING = $1E;
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Not supported |
ASN1_TAG_LONGFORM = $1F;
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Tag is encoded in long form |
ASN1_CLASS_UNIVERSAL = 0;
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ASN1_CLASS_APPLICATION = 1;
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ASN1_CLASS_CONTEXT_SPECIFIC = 2;
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ASN1_CLASS_PRIVATE = 3;
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ASN1_MAX_OID_LEN = 20;
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Type definitions
ASN1 tag
PASN1Tag = ^TASN1Tag;
TASN1Tag = record
TagNumber:LongWord;
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TagClass:LongWord;
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Length:LongWord;
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Constructed:Boolean;
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Contents:PByte;
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ASN1 OID
PASN1OID = ^TASN1OID;
TASN1OID = record
Len:Integer;
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OID:array[0..ASN1_MAX_OID_LEN - 1] of LongWord;
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Public variables
None defined
Function declarations
ASN1 functions
function ASN1GetTag(Buffer:PByte; Len:Integer; var Tag:TASN1Tag):Boolean;
Description: To be documented
| Note | None documented |
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function ASN1ParseOID(Buffer:PByte; Len:Integer; var OID:TASN1OID):Boolean;
Description: Parse an OID value from the buffer
| Note | None documented |
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function ASN1GetOID(Buffer:PByte; Len:Integer; var OID:TASN1OID; var Next:PByte):Boolean;
Description: Read the next ASN1 tag from buffer and decode it as an OID value
| Note | None documented |
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function ASN1GetNull(Buffer:PByte; Len:Integer; var Next:PByte):Boolean;
Description: Read the next ASN1 tag from buffer and decode it as a null value
| Note | None documented |
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function ASN1ParseInt(Buffer:PByte; Len:Integer; var Value:Integer):Boolean;
Description: Parse an integer value from the buffer
| Note | None documented |
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function ASN1ParseBigInt(Buffer:PByte; Len:Integer; var Value:PByte; var Size:Integer):Boolean;
Description: Parse a big integer value from the buffer (Does not include the leading negative byte if present)
| Note | Memory allocated for Value must be freed by the caller when no longer required |
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function ASN1GetInt(Buffer:PByte; Len:Integer; var Value:Integer; var Next:PByte):Boolean;
Description: Read the next ASN1 tag from buffer and decode it as an integer value
| Note | None documented |
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function ASN1ParseBoolean(Buffer:PByte; Len:Integer; var Value:Boolean):Boolean;
Description: Parse a boolean value from the buffer
| Note | None documented |
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function ASN1GetBoolean(Buffer:PByte; Len:Integer; var Value:Boolean; var Next:PByte):Boolean;
Description: Read the next ASN1 tag from buffer and decode it as a boolean value
| Note | None documented |
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ASN1 helper functions
function ASN1OIDEqual(const OID1,OID2:TASN1OID):Boolean;
Description: To be documented
| Note | None documented |
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function ASN1OIDEqualPrefix(const OIDPrefix,OID:TASN1OID):Boolean;
Description: To be documented
| Note | None documented |
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function ASN1OIDToString(const OID:TASN1OID):String;
Description: To be documented
| Note | None documented |
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function ASN1BitStringToLongWord(Buffer:PByte; Len:Integer):LongWord;
Description: To be documented
| Note | None documented |
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