github.com/jcmturner/gokrb5/v8@v8.4.4/crypto/aes256-cts-hmac-sha1-96.go (about)

     1  package crypto
     2  
     3  import (
     4  	"crypto/aes"
     5  	"crypto/hmac"
     6  	"crypto/sha1"
     7  	"hash"
     8  
     9  	"github.com/jcmturner/gokrb5/v8/crypto/common"
    10  	"github.com/jcmturner/gokrb5/v8/crypto/rfc3961"
    11  	"github.com/jcmturner/gokrb5/v8/crypto/rfc3962"
    12  	"github.com/jcmturner/gokrb5/v8/iana/chksumtype"
    13  	"github.com/jcmturner/gokrb5/v8/iana/etypeID"
    14  )
    15  
    16  // RFC 3962
    17  
    18  // Aes256CtsHmacSha96 implements Kerberos encryption type aes256-cts-hmac-sha1-96
    19  type Aes256CtsHmacSha96 struct {
    20  }
    21  
    22  // GetETypeID returns the EType ID number.
    23  func (e Aes256CtsHmacSha96) GetETypeID() int32 {
    24  	return etypeID.AES256_CTS_HMAC_SHA1_96
    25  }
    26  
    27  // GetHashID returns the checksum type ID number.
    28  func (e Aes256CtsHmacSha96) GetHashID() int32 {
    29  	return chksumtype.HMAC_SHA1_96_AES256
    30  }
    31  
    32  // GetKeyByteSize returns the number of bytes for key of this etype.
    33  func (e Aes256CtsHmacSha96) GetKeyByteSize() int {
    34  	return 256 / 8
    35  }
    36  
    37  // GetKeySeedBitLength returns the number of bits for the seed for key generation.
    38  func (e Aes256CtsHmacSha96) GetKeySeedBitLength() int {
    39  	return e.GetKeyByteSize() * 8
    40  }
    41  
    42  // GetHashFunc returns the hash function for this etype.
    43  func (e Aes256CtsHmacSha96) GetHashFunc() func() hash.Hash {
    44  	return sha1.New
    45  }
    46  
    47  // GetMessageBlockByteSize returns the block size for the etype's messages.
    48  func (e Aes256CtsHmacSha96) GetMessageBlockByteSize() int {
    49  	return 1
    50  }
    51  
    52  // GetDefaultStringToKeyParams returns the default key derivation parameters in string form.
    53  func (e Aes256CtsHmacSha96) GetDefaultStringToKeyParams() string {
    54  	return "00001000"
    55  }
    56  
    57  // GetConfounderByteSize returns the byte count for confounder to be used during cryptographic operations.
    58  func (e Aes256CtsHmacSha96) GetConfounderByteSize() int {
    59  	return aes.BlockSize
    60  }
    61  
    62  // GetHMACBitLength returns the bit count size of the integrity hash.
    63  func (e Aes256CtsHmacSha96) GetHMACBitLength() int {
    64  	return 96
    65  }
    66  
    67  // GetCypherBlockBitLength returns the bit count size of the cypher block.
    68  func (e Aes256CtsHmacSha96) GetCypherBlockBitLength() int {
    69  	return aes.BlockSize * 8
    70  }
    71  
    72  // StringToKey returns a key derived from the string provided.
    73  func (e Aes256CtsHmacSha96) StringToKey(secret string, salt string, s2kparams string) ([]byte, error) {
    74  	return rfc3962.StringToKey(secret, salt, s2kparams, e)
    75  }
    76  
    77  // RandomToKey returns a key from the bytes provided.
    78  func (e Aes256CtsHmacSha96) RandomToKey(b []byte) []byte {
    79  	return rfc3961.RandomToKey(b)
    80  }
    81  
    82  // EncryptData encrypts the data provided.
    83  func (e Aes256CtsHmacSha96) EncryptData(key, data []byte) ([]byte, []byte, error) {
    84  	return rfc3962.EncryptData(key, data, e)
    85  }
    86  
    87  // EncryptMessage encrypts the message provided and concatenates it with the integrity hash to create an encrypted message.
    88  func (e Aes256CtsHmacSha96) EncryptMessage(key, message []byte, usage uint32) ([]byte, []byte, error) {
    89  	return rfc3962.EncryptMessage(key, message, usage, e)
    90  }
    91  
    92  // DecryptData decrypts the data provided.
    93  func (e Aes256CtsHmacSha96) DecryptData(key, data []byte) ([]byte, error) {
    94  	return rfc3962.DecryptData(key, data, e)
    95  }
    96  
    97  // DecryptMessage decrypts the message provided and verifies the integrity of the message.
    98  func (e Aes256CtsHmacSha96) DecryptMessage(key, ciphertext []byte, usage uint32) ([]byte, error) {
    99  	return rfc3962.DecryptMessage(key, ciphertext, usage, e)
   100  }
   101  
   102  // DeriveKey derives a key from the protocol key based on the usage value.
   103  func (e Aes256CtsHmacSha96) DeriveKey(protocolKey, usage []byte) ([]byte, error) {
   104  	return rfc3961.DeriveKey(protocolKey, usage, e)
   105  }
   106  
   107  // DeriveRandom generates data needed for key generation.
   108  func (e Aes256CtsHmacSha96) DeriveRandom(protocolKey, usage []byte) ([]byte, error) {
   109  	return rfc3961.DeriveRandom(protocolKey, usage, e)
   110  }
   111  
   112  // VerifyIntegrity checks the integrity of the plaintext message.
   113  func (e Aes256CtsHmacSha96) VerifyIntegrity(protocolKey, ct, pt []byte, usage uint32) bool {
   114  	return rfc3961.VerifyIntegrity(protocolKey, ct, pt, usage, e)
   115  }
   116  
   117  // GetChecksumHash returns a keyed checksum hash of the bytes provided.
   118  func (e Aes256CtsHmacSha96) GetChecksumHash(protocolKey, data []byte, usage uint32) ([]byte, error) {
   119  	return common.GetHash(data, protocolKey, common.GetUsageKc(usage), e)
   120  }
   121  
   122  // VerifyChecksum compares the checksum of the message bytes is the same as the checksum provided.
   123  func (e Aes256CtsHmacSha96) VerifyChecksum(protocolKey, data, chksum []byte, usage uint32) bool {
   124  	c, err := e.GetChecksumHash(protocolKey, data, usage)
   125  	if err != nil {
   126  		return false
   127  	}
   128  	return hmac.Equal(chksum, c)
   129  }