B.2.3. RC2-CBC-Pad

B.2.3. RC2-CBC-Pad

RC2-CBC-Pad is the RC2 encryption algorithm [RFC2268] in CBC mode with the padding operation specified in RFC 1423 [RFC1423]. RC2-CBC-Pad has a variable key length, from one to 128 octets, a separate "effective key bits" parameter from one to 1024 bits that limits the effective search space independent of the key length, and an eight-octet initialization vector.

The object identifier rc2CBC identifies the RC2-CBC-Pad encryption scheme:

rc2CBC OBJECT IDENTIFIER ::= {encryptionAlgorithm 2}

The parameters field associated with OID in an AlgorithmIdentifier shall have type RC2-CBC-Parameter:

RC2-CBC-Parameter ::= SEQUENCE {
    rc2ParameterVersion INTEGER OPTIONAL,
    iv OCTET STRING (SIZE(8)) }

The fields of type RC2-CBCParameter have the following meanings:

• rc2ParameterVersion is a proprietary RSA Security Inc. encoding of the "effective key bits" for RC2. The following encodings are defined:

  Effective Key Bits	Encoding
  40	160
  64	120
  128	58
  b >= 256	b

  If the rc2ParameterVersion field is omitted, the "effective key bits" defaults to 32. (This is for backward compatibility with certain very old implementations.)

• iv is the eight-octet initialization vector.