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- from collections import namedtuple
-
- # Control flags
- FLAG_R = 1<<0
- FLAG_I = 1<<0
- DIR_CLIENT = 0
- DIR_SERVER = FLAG_I
- FLAG_A = 1<<1
- FLAG_C = 1<<2
- FLAG_T = 1<<3
- FLAG_M = 1<<4
- FLAG_K = 1<<5
-
- # Record defining a STROBE control word
- class ControlWord(namedtuple("ControlWord",("name",
- "bytes","dmode","cmode",
- "length_bytes","length","max_length","min_length"))):
-
- """
- Control word for STROBE.
-
- TODO: write more docs
- """
-
- def __new__(cls,name,
- bytes,dmode,cmode=None,
- length_bytes=0,length=None,max_length=None,min_length=None,explicit=None):
-
- if explicit is None:
- explicit = (len(bytes) or length_bytes) and (dmode & FLAG_T)
-
- if cmode is None:
- # Default: Don't send unless there are length bytes and transport
- if explicit: cmode = FLAG_A | FLAG_T | FLAG_M
- else: cmode = FLAG_A | FLAG_M
-
- bytes = bytearray(bytes)
- if dmode & (FLAG_T | FLAG_A) == 0 and length_bytes == 0 and length is None:
- length = 0
-
- return super(ControlWord,cls).__new__(cls,name,
- bytes,dmode,cmode,
- length_bytes,length,max_length,min_length)
-
- def __str__(self): return self.name
-
- TYPE_META = 0
- TYPE_ABSORB = FLAG_A
- TYPE_PLAINTEXT = FLAG_A | FLAG_T
- TYPE_ENCRYPT = FLAG_A | FLAG_T | FLAG_C
- TYPE_MAC = FLAG_T | FLAG_C
- TYPE_PRNG = FLAG_A | FLAG_C
- TYPE_RATCHET = FLAG_C # to be used with extract
- TYPE_KEY = FLAG_A | FLAG_C
-
- ################################################################################
- # Example control words.
- #
- # The STROBE lite framework is not tied to any of these definitions.
- # These are just some examples / recommendations of what you can use.
- #
- # These code words span the gamut from offline encrypted and/or signed messages,
- # to full TLS-like protocols.
- #
- # ***
- # The assumption is that most protocols will use a VERY SMALL SUBSET of these tags.
- # They are comprehensive just to demonstrate that you could replace TLS with a
- # protocol like this.
- # ***
- ################################################################################
-
- # 0x00-0x0F: symmetric cryptography
- SYM_SCHEME = ControlWord("SYM_SCHEME", [0x00], TYPE_PLAINTEXT , length_bytes=2)
- SYM_KEY = ControlWord("SYM_KEY", [0x01], TYPE_KEY )
- APP_PLAINTEXT = ControlWord("APP_PLAINTEXT", [0x02], TYPE_PLAINTEXT , length_bytes=2)
- APP_CIPHERTEXT = ControlWord("APP_CIPHERTEXT", [0x03], TYPE_ENCRYPT , length_bytes=2)
- AUTH_DATA = ControlWord("NONCE", [0x04], TYPE_PLAINTEXT , length_bytes=2)
- AUTH_DATA = ControlWord("AUTH_DATA", [0x05], TYPE_PLAINTEXT , length_bytes=2)
- MAC = ControlWord("MAC", [0x06], TYPE_MAC , length_bytes=2, length=16, explicit=False )
- STEG_MAC = ControlWord("STEG_MAC", [0x06], TYPE_MAC , length_bytes=2, min_length=16, cmode=TYPE_ENCRYPT|FLAG_M)
- SIV_MAC_INNER = ControlWord("SIV_MAC_INNER", [0x06], TYPE_MAC , length_bytes=2, length=16, explicit=False )
- HASH = ControlWord("HASH", [0x07], TYPE_PRNG , length_bytes=2, explicit=False )
- SIV_PT_INNER = ControlWord("SIV_PT_INNER", [0x0D], TYPE_PLAINTEXT , explicit=False)
- SIV_MAC_OUTER = ControlWord("SIV_MAC_OUTER", [0x0E], TYPE_PLAINTEXT , length=16)
- RATCHET = ControlWord("RATCHET", [0x0F], TYPE_RATCHET , length=32)
-
- # 0x10-0x1F: Asymmetric key exchange and encryption */
- KEM_SCHEME = ControlWord("KEM_SCHEME", [0x10], TYPE_PLAINTEXT , length_bytes=2)
- PUBLIC_KEY = ControlWord("PUBLIC_KEY", [0x11], TYPE_PLAINTEXT , length_bytes=2)
- KEM_EPH = ControlWord("KEM_EPH", [0x12], TYPE_PLAINTEXT , length_bytes=2)
- KEM_RESULT = ControlWord("KEM_RESULT", [0x13], TYPE_KEY )
-
- # 0x18-0x1F: Signatures */
- SIG_SCHEME = ControlWord("SIG_SCHEME", [0x18], TYPE_PLAINTEXT , length_bytes=2)
- SIG_EPH = ControlWord("SIG_EPH", [0x19], TYPE_PLAINTEXT , length_bytes=2)
- SIG_CHALLENGE = ControlWord("SIG_CHALLENGE", [0x1A], TYPE_PRNG , length_bytes=2, explicit=False)
- SIG_RESPONSE = ControlWord("SIG_RESPONSE", [0x1B], TYPE_ENCRYPT , length_bytes=2)
-
- # 0x00-0x0F: header and other metadata */
- HANDSHAKE = ControlWord("HANDSHAKE", [0x20], TYPE_PLAINTEXT , length_bytes=2)
- VERSION = ControlWord("VERSION", [0x21], TYPE_PLAINTEXT , length_bytes=2)
- CIPHERSUITE = ControlWord("CIPHERSUITE", [0x22], TYPE_PLAINTEXT , length_bytes=2)
- META_PLAINTEXT = ControlWord("META_PLAINTEXT", [0x24], TYPE_PLAINTEXT , length_bytes=2)
- META_CIPHERTEXT= ControlWord("META_CIPHERTEXT", [0x25], TYPE_PLAINTEXT , length_bytes=2)
- CERTIFICATE = ControlWord("CERTIFICATE", [0x26], TYPE_PLAINTEXT , length_bytes=2)
- ENCRYPTED_CERT = ControlWord("ENCRYPTED_CERT", [0x27], TYPE_ENCRYPT , length_bytes=2)
- OVER = ControlWord("OVER", [0x2E], TYPE_MAC , length_bytes=2)
- CLOSE = ControlWord("CLOSE", [0x2F], TYPE_MAC , length_bytes=2)
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