#include <hkdf.h>

Inheritance diagram for Botan::HKDF_Expand:

Public Member Functions
KDF *	clone () const override

secure_vector< uint8_t >	derive_key (size_t key_len, const uint8_t secret[], size_t secret_len, const uint8_t salt[], size_t salt_len, const uint8_t label[]=nullptr, size_t label_len=0) const

secure_vector< uint8_t >	derive_key (size_t key_len, const secure_vector< uint8_t > &secret, const std::string &salt="", const std::string &label="") const

template<typename Alloc , typename Alloc2 , typename Alloc3 >
secure_vector< uint8_t >	derive_key (size_t key_len, const std::vector< uint8_t, Alloc > &secret, const std::vector< uint8_t, Alloc2 > &salt, const std::vector< uint8_t, Alloc3 > &label) const

secure_vector< uint8_t >	derive_key (size_t key_len, const secure_vector< uint8_t > &secret, const uint8_t salt[], size_t salt_len, const std::string &label="") const

secure_vector< uint8_t >	derive_key (size_t key_len, const uint8_t secret[], size_t secret_len, const std::string &salt="", const std::string &label="") const

	HKDF_Expand (MessageAuthenticationCode *prf)

size_t	kdf (uint8_t key[], size_t key_len, const uint8_t secret[], size_t secret_len, const uint8_t salt[], size_t salt_len, const uint8_t label[], size_t label_len) const override

std::string	name () const override

Static Public Member Functions
static std::unique_ptr< KDF >	create (const std::string &algo_spec, const std::string &provider="")

static std::unique_ptr< KDF >	create_or_throw (const std::string &algo_spec, const std::string &provider="")

static std::vector< std::string >	providers (const std::string &algo_spec)

Detailed Description

HKDF Expansion Step from RFC 5869.

Definition at line 74 of file hkdf.h.

Constructor & Destructor Documentation

◆ HKDF_Expand()

Botan::HKDF_Expand::HKDF_Expand ( MessageAuthenticationCode * prf )

inlineexplicit

Parameters

prf	MAC algorithm to use

Definition at line 80 of file hkdf.h.

80 : m_prf(prf) {}

Member Function Documentation

◆ clone()

KDF* Botan::HKDF_Expand::clone ( ) const

inlineoverridevirtual

Returns: new object representing the same algorithm as *this

Implements Botan::KDF.

Definition at line 82 of file hkdf.h.

82 { return new HKDF_Expand(m_prf->clone()); }

Botan::HKDF_Expand::HKDF_Expand

HKDF_Expand(MessageAuthenticationCode *prf)

Definition: hkdf.h:80

◆ create()

std::unique_ptr< KDF > Botan::KDF::create	(	const std::string &	algo_spec,
		const std::string &	provider = `""`
	)

staticinherited

Create an instance based on a name If provider is empty then best available is chosen.

Parameters

algo_spec	algorithm name
provider	provider implementation to choose

Returns: a null pointer if the algo/provider combination cannot be found

Definition at line 69 of file kdf.cpp.

References Botan::SCAN_Name::algo_name(), Botan::SCAN_Name::arg(), Botan::SCAN_Name::arg_count(), BOTAN_UNUSED, Botan::HashFunction::create(), Botan::MessageAuthenticationCode::create(), and hash.

Referenced by Botan::KDF::create_or_throw(), and Botan::get_kdf().

    {
    const SCAN_Name req(algo_spec);
 
 #if defined(BOTAN_HAS_HKDF)
    if(req.algo_name() == "HKDF" && req.arg_count() == 1)
       {
       if(provider.empty() || provider == "base")
          {
          return kdf_create_mac_or_hash<HKDF>(req.arg(0));
          }
       }
 
    if(req.algo_name() == "HKDF-Extract" && req.arg_count() == 1)
       {
       if(provider.empty() || provider == "base")
          {
          return kdf_create_mac_or_hash<HKDF_Extract>(req.arg(0));
          }
       }
 
    if(req.algo_name() == "HKDF-Expand" && req.arg_count() == 1)
       {
       if(provider.empty() || provider == "base")
          {
          return kdf_create_mac_or_hash<HKDF_Expand>(req.arg(0));
          }
       }
 #endif
 
 #if defined(BOTAN_HAS_KDF2)
    if(req.algo_name() == "KDF2" && req.arg_count() == 1)
       {
       if(provider.empty() || provider == "base")
          {
          if(auto hash = HashFunction::create(req.arg(0)))
             return std::unique_ptr<KDF>(new KDF2(hash.release()));
          }
       }
 #endif
 
 #if defined(BOTAN_HAS_KDF1_18033)
    if(req.algo_name() == "KDF1-18033" && req.arg_count() == 1)
       {
       if(provider.empty() || provider == "base")
          {
          if(auto hash = HashFunction::create(req.arg(0)))
             return std::unique_ptr<KDF>(new KDF1_18033(hash.release()));
          }
       }
 #endif
 
 #if defined(BOTAN_HAS_KDF1)
    if(req.algo_name() == "KDF1" && req.arg_count() == 1)
       {
       if(provider.empty() || provider == "base")
          {
          if(auto hash = HashFunction::create(req.arg(0)))
             return std::unique_ptr<KDF>(new KDF1(hash.release()));
          }
       }
 #endif
 
 #if defined(BOTAN_HAS_TLS_V10_PRF)
    if(req.algo_name() == "TLS-PRF" && req.arg_count() == 0)
       {
       if(provider.empty() || provider == "base")
          {
          auto hmac_md5 = MessageAuthenticationCode::create("HMAC(MD5)");
          auto hmac_sha1 = MessageAuthenticationCode::create("HMAC(SHA-1)");
 
          if(hmac_md5 && hmac_sha1)
             return std::unique_ptr<KDF>(new TLS_PRF(std::move(hmac_md5), std::move(hmac_sha1)));
          }
       }
 #endif
 
 #if defined(BOTAN_HAS_TLS_V12_PRF)
    if(req.algo_name() == "TLS-12-PRF" && req.arg_count() == 1)
       {
       if(provider.empty() || provider == "base")
          {
          return kdf_create_mac_or_hash<TLS_12_PRF>(req.arg(0));
          }
       }
 #endif
 
 #if defined(BOTAN_HAS_X942_PRF)
    if(req.algo_name() == "X9.42-PRF" && req.arg_count() == 1)
       {
       if(provider.empty() || provider == "base")
          {
          return std::unique_ptr<KDF>(new X942_PRF(req.arg(0)));
          }
       }
 #endif
 
 #if defined(BOTAN_HAS_SP800_108)
    if(req.algo_name() == "SP800-108-Counter" && req.arg_count() == 1)
       {
       if(provider.empty() || provider == "base")
          {
          return kdf_create_mac_or_hash<SP800_108_Counter>(req.arg(0));
          }
       }
 
    if(req.algo_name() == "SP800-108-Feedback" && req.arg_count() == 1)
       {
       if(provider.empty() || provider == "base")
          {
          return kdf_create_mac_or_hash<SP800_108_Feedback>(req.arg(0));
          }
       }
 
    if(req.algo_name() == "SP800-108-Pipeline" && req.arg_count() == 1)
       {
       if(provider.empty() || provider == "base")
          {
          return kdf_create_mac_or_hash<SP800_108_Pipeline>(req.arg(0));
          }
       }
 #endif
 
 #if defined(BOTAN_HAS_SP800_56A)
    if(req.algo_name() == "SP800-56A" && req.arg_count() == 1)
       {
       if(auto hash = HashFunction::create(req.arg(0)))
          return std::unique_ptr<KDF>(new SP800_56A_Hash(hash.release()));
       if(auto mac = MessageAuthenticationCode::create(req.arg(0)))
          return std::unique_ptr<KDF>(new SP800_56A_HMAC(mac.release()));
       }
 #endif
 
 #if defined(BOTAN_HAS_SP800_56C)
    if(req.algo_name() == "SP800-56C" && req.arg_count() == 1)
       {
       std::unique_ptr<KDF> exp(kdf_create_mac_or_hash<SP800_108_Feedback>(req.arg(0)));
       if(exp)
          {
          if(auto mac = MessageAuthenticationCode::create(req.arg(0)))
             return std::unique_ptr<KDF>(new SP800_56C(mac.release(), exp.release()));
 
          if(auto mac = MessageAuthenticationCode::create("HMAC(" + req.arg(0) + ")"))
             return std::unique_ptr<KDF>(new SP800_56C(mac.release(), exp.release()));
          }
       }
 #endif
 
    BOTAN_UNUSED(req);
    BOTAN_UNUSED(provider);
 
    return nullptr;
    }

◆ create_or_throw()

std::unique_ptr< KDF > Botan::KDF::create_or_throw	(	const std::string &	algo_spec,
		const std::string &	provider = `""`
	)

staticinherited

Create an instance based on a name, or throw if the algo/provider combination cannot be found. If provider is empty then best available is chosen.

Definition at line 226 of file kdf.cpp.

References Botan::KDF::create(), and Botan::KDF::kdf().

Referenced by Botan::ECIES_KA_Operation::derive_secret().

    {
    if(auto kdf = KDF::create(algo, provider))
       {
       return kdf;
       }
    throw Lookup_Error("KDF", algo, provider);
    }

◆ derive_key() [1/5]

secure_vector<uint8_t> Botan::KDF::derive_key	(	size_t	key_len,
		const uint8_t	secret[],
		size_t	secret_len,
		const uint8_t	salt[],
		size_t	salt_len,
		const uint8_t	label[] = `nullptr`,
		size_t	label_len = `0`
	)		const

inlineinherited

Derive a key

Parameters

key_len	the desired output length in bytes
secret	the secret input
secret_len	size of secret in bytes
salt	a diversifier
salt_len	size of salt in bytes
label	purpose for the derived keying material
label_len	size of label in bytes

Returns: the derived key

Definition at line 83 of file kdf.h.

References salt_len.

          {
          secure_vector<uint8_t> key(key_len);
          key.resize(kdf(key.data(), key.size(), secret, secret_len, salt, salt_len, label, label_len));
          return key;
          }

◆ derive_key() [2/5]

secure_vector<uint8_t> Botan::KDF::derive_key	(	size_t	key_len,
		const secure_vector< uint8_t > &	secret,
		const std::string &	salt = `""`,
		const std::string &	label = `""`
	)		const

inlineinherited

Derive a key

Parameters

key_len	the desired output length in bytes
secret	the secret input
salt	a diversifier
label	purpose for the derived keying material

Returns: the derived key

Definition at line 104 of file kdf.h.

References Botan::cast_char_ptr_to_uint8().

          {
          return derive_key(key_len, secret.data(), secret.size(),
                            cast_char_ptr_to_uint8(salt.data()),
                            salt.length(),
                            cast_char_ptr_to_uint8(label.data()),
                            label.length());
 
          }

◆ derive_key() [3/5]

template<typename Alloc , typename Alloc2 , typename Alloc3 >

secure_vector<uint8_t> Botan::KDF::derive_key	(	size_t	key_len,
		const std::vector< uint8_t, Alloc > &	secret,
		const std::vector< uint8_t, Alloc2 > &	salt,
		const std::vector< uint8_t, Alloc3 > &	label
	)		const

inlineinherited

Derive a key

Parameters

key_len	the desired output length in bytes
secret	the secret input
salt	a diversifier
label	purpose for the derived keying material

Returns: the derived key

Definition at line 126 of file kdf.h.

          {
          return derive_key(key_len,
                            secret.data(), secret.size(),
                            salt.data(), salt.size(),
                            label.data(), label.size());
          }

◆ derive_key() [4/5]

secure_vector<uint8_t> Botan::KDF::derive_key	(	size_t	key_len,
		const secure_vector< uint8_t > &	secret,
		const uint8_t	salt[],
		size_t	salt_len,
		const std::string &	label = `""`
	)		const

inlineinherited

Derive a key

Parameters

key_len	the desired output length in bytes
secret	the secret input
salt	a diversifier
salt_len	size of salt in bytes
label	purpose for the derived keying material

Returns: the derived key

Definition at line 146 of file kdf.h.

References Botan::cast_char_ptr_to_uint8(), and salt_len.

          {
          return derive_key(key_len,
                            secret.data(), secret.size(),
                            salt, salt_len,
                            cast_char_ptr_to_uint8(label.data()),
                            label.size());
          }

◆ derive_key() [5/5]

secure_vector<uint8_t> Botan::KDF::derive_key	(	size_t	key_len,
		const uint8_t	secret[],
		size_t	secret_len,
		const std::string &	salt = `""`,
		const std::string &	label = `""`
	)		const

inlineinherited

Derive a key

Parameters

key_len	the desired output length in bytes
secret	the secret input
secret_len	size of secret in bytes
salt	a diversifier
label	purpose for the derived keying material

Returns: the derived key

Definition at line 168 of file kdf.h.

References Botan::cast_char_ptr_to_uint8().

          {
          return derive_key(key_len, secret, secret_len,
                            cast_char_ptr_to_uint8(salt.data()),
                            salt.length(),
                            cast_char_ptr_to_uint8(label.data()),
                            label.length());
          }

◆ kdf()

size_t Botan::HKDF_Expand::kdf	(	uint8_t	key[],
		size_t	key_len,
		const uint8_t	secret[],
		size_t	secret_len,
		const uint8_t	salt[],
		size_t	salt_len,
		const uint8_t	label[],
		size_t	label_len
	)		const

overridevirtual

Derive a key

Parameters

key	buffer holding the derived key, must be of length key_len
key_len	the desired output length in bytes
secret	the secret input
secret_len	size of secret in bytes
salt	a diversifier
salt_len	size of salt in bytes
label	purpose for the derived keying material
label_len	size of label in bytes

Returns: the derived key

Implements Botan::KDF.

Definition at line 50 of file hkdf.cpp.

References Botan::copy_mem(), and salt_len.

Referenced by Botan::HKDF::kdf().

    {
    m_prf->set_key(secret, secret_len);
 
    uint8_t counter = 1;
    secure_vector<uint8_t> h;
    size_t offset = 0;
 
    while(offset != key_len && counter != 0)
       {
       m_prf->update(h);
       m_prf->update(label, label_len);
       m_prf->update(salt, salt_len);
       m_prf->update(counter++);
       m_prf->final(h);
 
       const size_t written = std::min(h.size(), key_len - offset);
       copy_mem(&key[offset], h.data(), written);
       offset += written;
       }
 
    return offset;
    }

◆ name()

std::string Botan::HKDF_Expand::name ( ) const

inlineoverridevirtual

Returns: KDF name

Implements Botan::KDF.

Definition at line 84 of file hkdf.h.

84 { return "HKDF-Expand(" + m_prf->name() + ")"; }

◆ providers()

std::vector< std::string > Botan::KDF::providers ( const std::string & algo_spec )

staticinherited

Returns: list of available providers for this algorithm, empty if not available

Definition at line 236 of file kdf.cpp.

    {
    return probe_providers_of<KDF>(algo_spec, { "base" });
    }

The documentation for this class was generated from the following files:

src/lib/kdf/hkdf/hkdf.h
src/lib/kdf/hkdf/hkdf.cpp

Public Member Functions

Static Public Member Functions

Detailed Description

Constructor & Destructor Documentation

◆ HKDF_Expand()

Member Function Documentation

◆ clone()

◆ create()

◆ create_or_throw()

◆ derive_key() [1/5]

◆ derive_key() [2/5]

◆ derive_key() [3/5]

◆ derive_key() [4/5]

◆ derive_key() [5/5]

◆ kdf()

◆ name()

◆ providers()