aes256-cts-hmac-sha1-96.go
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package crypto
import (
"crypto/aes"
"crypto/hmac"
"crypto/sha1"
"hash"
"gopkg.in/jcmturner/gokrb5.v7/crypto/common"
"gopkg.in/jcmturner/gokrb5.v7/crypto/rfc3961"
"gopkg.in/jcmturner/gokrb5.v7/crypto/rfc3962"
"gopkg.in/jcmturner/gokrb5.v7/iana/chksumtype"
"gopkg.in/jcmturner/gokrb5.v7/iana/etypeID"
)
// RFC 3962
//+--------------------------------------------------------------------+
//| protocol key format 128- or 256-bit string |
//| |
//| string-to-key function PBKDF2+DK with variable |
//| iteration count (see |
//| above) |
//| |
//| default string-to-key parameters 00 00 10 00 |
//| |
//| key-generation seed length key size |
//| |
//| random-to-key function identity function |
//| |
//| hash function, H SHA-1 |
//| |
//| HMAC output size, h 12 octets (96 bits) |
//| |
//| message block size, m 1 octet |
//| |
//| encryption/decryption functions, AES in CBC-CTS mode |
//| E and D (cipher block size 16 |
//| octets), with next-to- |
//| last block (last block |
//| if only one) as CBC-style |
//| ivec |
//+--------------------------------------------------------------------+
//
//+--------------------------------------------------------------------+
//| encryption types |
//+--------------------------------------------------------------------+
//| type name etype value key size |
//+--------------------------------------------------------------------+
//| aes128-cts-hmac-sha1-96 17 128 |
//| aes256-cts-hmac-sha1-96 18 256 |
//+--------------------------------------------------------------------+
//
//+--------------------------------------------------------------------+
//| checksum types |
//+--------------------------------------------------------------------+
//| type name sumtype value length |
//+--------------------------------------------------------------------+
//| hmac-sha1-96-aes128 15 96 |
//| hmac-sha1-96-aes256 16 96 |
//+--------------------------------------------------------------------+
// Aes256CtsHmacSha96 implements Kerberos encryption type aes256-cts-hmac-sha1-96
type Aes256CtsHmacSha96 struct {
}
// GetETypeID returns the EType ID number.
func (e Aes256CtsHmacSha96) GetETypeID() int32 {
return etypeID.AES256_CTS_HMAC_SHA1_96
}
// GetHashID returns the checksum type ID number.
func (e Aes256CtsHmacSha96) GetHashID() int32 {
return chksumtype.HMAC_SHA1_96_AES256
}
// GetKeyByteSize returns the number of bytes for key of this etype.
func (e Aes256CtsHmacSha96) GetKeyByteSize() int {
return 256 / 8
}
// GetKeySeedBitLength returns the number of bits for the seed for key generation.
func (e Aes256CtsHmacSha96) GetKeySeedBitLength() int {
return e.GetKeyByteSize() * 8
}
// GetHashFunc returns the hash function for this etype.
func (e Aes256CtsHmacSha96) GetHashFunc() func() hash.Hash {
return sha1.New
}
// GetMessageBlockByteSize returns the block size for the etype's messages.
func (e Aes256CtsHmacSha96) GetMessageBlockByteSize() int {
return 1
}
// GetDefaultStringToKeyParams returns the default key derivation parameters in string form.
func (e Aes256CtsHmacSha96) GetDefaultStringToKeyParams() string {
return "00001000"
}
// GetConfounderByteSize returns the byte count for confounder to be used during cryptographic operations.
func (e Aes256CtsHmacSha96) GetConfounderByteSize() int {
return aes.BlockSize
}
// GetHMACBitLength returns the bit count size of the integrity hash.
func (e Aes256CtsHmacSha96) GetHMACBitLength() int {
return 96
}
// GetCypherBlockBitLength returns the bit count size of the cypher block.
func (e Aes256CtsHmacSha96) GetCypherBlockBitLength() int {
return aes.BlockSize * 8
}
// StringToKey returns a key derived from the string provided.
func (e Aes256CtsHmacSha96) StringToKey(secret string, salt string, s2kparams string) ([]byte, error) {
return rfc3962.StringToKey(secret, salt, s2kparams, e)
}
// RandomToKey returns a key from the bytes provided.
func (e Aes256CtsHmacSha96) RandomToKey(b []byte) []byte {
return rfc3961.RandomToKey(b)
}
// EncryptData encrypts the data provided.
func (e Aes256CtsHmacSha96) EncryptData(key, data []byte) ([]byte, []byte, error) {
return rfc3962.EncryptData(key, data, e)
}
// EncryptMessage encrypts the message provided and concatenates it with the integrity hash to create an encrypted message.
func (e Aes256CtsHmacSha96) EncryptMessage(key, message []byte, usage uint32) ([]byte, []byte, error) {
return rfc3962.EncryptMessage(key, message, usage, e)
}
// DecryptData decrypts the data provided.
func (e Aes256CtsHmacSha96) DecryptData(key, data []byte) ([]byte, error) {
return rfc3962.DecryptData(key, data, e)
}
// DecryptMessage decrypts the message provided and verifies the integrity of the message.
func (e Aes256CtsHmacSha96) DecryptMessage(key, ciphertext []byte, usage uint32) ([]byte, error) {
return rfc3962.DecryptMessage(key, ciphertext, usage, e)
}
// DeriveKey derives a key from the protocol key based on the usage value.
func (e Aes256CtsHmacSha96) DeriveKey(protocolKey, usage []byte) ([]byte, error) {
return rfc3961.DeriveKey(protocolKey, usage, e)
}
// DeriveRandom generates data needed for key generation.
func (e Aes256CtsHmacSha96) DeriveRandom(protocolKey, usage []byte) ([]byte, error) {
return rfc3961.DeriveRandom(protocolKey, usage, e)
}
// VerifyIntegrity checks the integrity of the plaintext message.
func (e Aes256CtsHmacSha96) VerifyIntegrity(protocolKey, ct, pt []byte, usage uint32) bool {
return rfc3961.VerifyIntegrity(protocolKey, ct, pt, usage, e)
}
// GetChecksumHash returns a keyed checksum hash of the bytes provided.
func (e Aes256CtsHmacSha96) GetChecksumHash(protocolKey, data []byte, usage uint32) ([]byte, error) {
return common.GetHash(data, protocolKey, common.GetUsageKc(usage), e)
}
// VerifyChecksum compares the checksum of the message bytes is the same as the checksum provided.
func (e Aes256CtsHmacSha96) VerifyChecksum(protocolKey, data, chksum []byte, usage uint32) bool {
c, err := e.GetChecksumHash(protocolKey, data, usage)
if err != nil {
return false
}
return hmac.Equal(chksum, c)
}