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Merged
sjaeckel merged 1 commit into from
Apr 14, 2026
Merged

The scrypt Password-Based Key Derivation Function (RFC 7914) #719

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27 changes: 27 additions & 0 deletions doc/crypt.tex
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Expand Up @@ -7629,6 +7629,33 @@ \subsection{Argon2}
The function returns \texttt{CRYPT\_OK} on success, \texttt{CRYPT\_MEM} if memory allocation fails, or \texttt{CRYPT\_INVALID\_ARG} if any parameter is out of range.


\subsection{scrypt}
\index{scrypt}
\label{scrypt}

scrypt is a memory-hard password-based key derivation function defined in \href{https://datatracker.ietf.org/doc/html/rfc7914}{\texttt{RFC 7914}}.
It is designed so that a large amount of memory is required for evaluation, making hardware brute-force attacks more costly.
Internally it uses PBKDF2-HMAC-SHA-256 and a reduced-round Salsa20 core.

To enable scrypt, define \texttt{LTC\_SCRYPT} in \textit{tomcrypt\_custom.h} (it also requires \texttt{LTC\_PKCS\_5} and \texttt{LTC\_SHA256}).

\index{scrypt\_pbkdf()}
\begin{alltt}
int scrypt_pbkdf(const unsigned char *password, unsigned long password_len,
const unsigned char *salt, unsigned long salt_len,
unsigned long N, unsigned long r, unsigned long p,
unsigned char *out, unsigned long outlen);
\end{alltt}

The \textit{password} parameter is the password of length \textit{password\_len}.
The \textit{salt} parameter is a random salt of length \textit{salt\_len}.
The \textit{N} parameter is the CPU/memory cost; it must be greater than 1 and a power of 2.
The \textit{r} parameter is the block size (minimum 1; a typical value is 8).
The \textit{p} parameter is the parallelisation factor (minimum 1); this implementation is single-threaded, so increasing \textit{p} raises the computational cost without improving performance.
The derived key of length \textit{outlen} is written to \textit{out}.
The function returns \texttt{CRYPT\_OK} on success or an error code on failure.


\mysection{PKCS \#8}
\index{PKCS \#8}
\label{pkcs8}
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8 changes: 8 additions & 0 deletions libtomcrypt_VS2008.vcproj
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Expand Up @@ -1675,6 +1675,14 @@
>
</File>
</Filter>
<Filter
Name="scrypt"
>
<File
RelativePath="src\misc\scrypt\scrypt.c"
>
</File>
</Filter>
<Filter
Name="ssh"
>
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17 changes: 9 additions & 8 deletions makefile.mingw
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Expand Up @@ -116,13 +116,14 @@ src/misc/padding/padding_pad.o src/misc/password_free.o src/misc/pbes/pbes.o src
src/misc/pbes/pbes2.o src/misc/pem/pem.o src/misc/pem/pem_pkcs.o src/misc/pem/pem_read.o \
src/misc/pem/pem_ssh.o src/misc/pkcs12/pkcs12_kdf.o src/misc/pkcs12/pkcs12_utf8_to_utf16.o \
src/misc/pkcs5/pkcs_5_1.o src/misc/pkcs5/pkcs_5_2.o src/misc/pkcs5/pkcs_5_test.o \
src/misc/ssh/ssh_decode_sequence_multi.o src/misc/ssh/ssh_encode_sequence_multi.o src/misc/zeromem.o \
src/modes/cbc/cbc_decrypt.o src/modes/cbc/cbc_done.o src/modes/cbc/cbc_encrypt.o \
src/modes/cbc/cbc_getiv.o src/modes/cbc/cbc_setiv.o src/modes/cbc/cbc_start.o \
src/modes/cfb/cfb_decrypt.o src/modes/cfb/cfb_done.o src/modes/cfb/cfb_encrypt.o \
src/modes/cfb/cfb_getiv.o src/modes/cfb/cfb_setiv.o src/modes/cfb/cfb_start.o \
src/modes/ctr/ctr_decrypt.o src/modes/ctr/ctr_done.o src/modes/ctr/ctr_encrypt.o \
src/modes/ctr/ctr_getiv.o src/modes/ctr/ctr_setiv.o src/modes/ctr/ctr_start.o src/modes/ctr/ctr_test.o \
src/misc/scrypt/scrypt.o src/misc/ssh/ssh_decode_sequence_multi.o \
src/misc/ssh/ssh_encode_sequence_multi.o src/misc/zeromem.o src/modes/cbc/cbc_decrypt.o \
src/modes/cbc/cbc_done.o src/modes/cbc/cbc_encrypt.o src/modes/cbc/cbc_getiv.o \
src/modes/cbc/cbc_setiv.o src/modes/cbc/cbc_start.o src/modes/cfb/cfb_decrypt.o \
src/modes/cfb/cfb_done.o src/modes/cfb/cfb_encrypt.o src/modes/cfb/cfb_getiv.o \
src/modes/cfb/cfb_setiv.o src/modes/cfb/cfb_start.o src/modes/ctr/ctr_decrypt.o \
src/modes/ctr/ctr_done.o src/modes/ctr/ctr_encrypt.o src/modes/ctr/ctr_getiv.o \
src/modes/ctr/ctr_setiv.o src/modes/ctr/ctr_start.o src/modes/ctr/ctr_test.o \
src/modes/ecb/ecb_decrypt.o src/modes/ecb/ecb_done.o src/modes/ecb/ecb_encrypt.o \
src/modes/ecb/ecb_start.o src/modes/f8/f8_decrypt.o src/modes/f8/f8_done.o src/modes/f8/f8_encrypt.o \
src/modes/f8/f8_getiv.o src/modes/f8/f8_setiv.o src/modes/f8/f8_start.o src/modes/f8/f8_test_mode.o \
Expand Down Expand Up @@ -242,7 +243,7 @@ tests/misc_test.o tests/modes_test.o tests/mpi_test.o tests/multi_test.o \
tests/no_null_termination_check_test.o tests/no_prng.o tests/padding_test.o tests/pem_test.o \
tests/pk_oid_test.o tests/pkcs_1_eme_test.o tests/pkcs_1_emsa_test.o tests/pkcs_1_oaep_test.o \
tests/pkcs_1_pss_test.o tests/pkcs_1_test.o tests/prng_test.o tests/rotate_test.o tests/rsa_test.o \
tests/ssh_test.o tests/store_test.o tests/test.o tests/x25519_test.o
tests/scrypt_test.o tests/ssh_test.o tests/store_test.o tests/test.o tests/x25519_test.o

#The following headers will be installed by "make install"
HEADERS_PUB=src/headers/tomcrypt.h src/headers/tomcrypt_argchk.h src/headers/tomcrypt_cfg.h \
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17 changes: 9 additions & 8 deletions makefile.msvc
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Expand Up @@ -109,13 +109,14 @@ src/misc/padding/padding_pad.obj src/misc/password_free.obj src/misc/pbes/pbes.o
src/misc/pbes/pbes2.obj src/misc/pem/pem.obj src/misc/pem/pem_pkcs.obj src/misc/pem/pem_read.obj \
src/misc/pem/pem_ssh.obj src/misc/pkcs12/pkcs12_kdf.obj src/misc/pkcs12/pkcs12_utf8_to_utf16.obj \
src/misc/pkcs5/pkcs_5_1.obj src/misc/pkcs5/pkcs_5_2.obj src/misc/pkcs5/pkcs_5_test.obj \
src/misc/ssh/ssh_decode_sequence_multi.obj src/misc/ssh/ssh_encode_sequence_multi.obj src/misc/zeromem.obj \
src/modes/cbc/cbc_decrypt.obj src/modes/cbc/cbc_done.obj src/modes/cbc/cbc_encrypt.obj \
src/modes/cbc/cbc_getiv.obj src/modes/cbc/cbc_setiv.obj src/modes/cbc/cbc_start.obj \
src/modes/cfb/cfb_decrypt.obj src/modes/cfb/cfb_done.obj src/modes/cfb/cfb_encrypt.obj \
src/modes/cfb/cfb_getiv.obj src/modes/cfb/cfb_setiv.obj src/modes/cfb/cfb_start.obj \
src/modes/ctr/ctr_decrypt.obj src/modes/ctr/ctr_done.obj src/modes/ctr/ctr_encrypt.obj \
src/modes/ctr/ctr_getiv.obj src/modes/ctr/ctr_setiv.obj src/modes/ctr/ctr_start.obj src/modes/ctr/ctr_test.obj \
src/misc/scrypt/scrypt.obj src/misc/ssh/ssh_decode_sequence_multi.obj \
src/misc/ssh/ssh_encode_sequence_multi.obj src/misc/zeromem.obj src/modes/cbc/cbc_decrypt.obj \
src/modes/cbc/cbc_done.obj src/modes/cbc/cbc_encrypt.obj src/modes/cbc/cbc_getiv.obj \
src/modes/cbc/cbc_setiv.obj src/modes/cbc/cbc_start.obj src/modes/cfb/cfb_decrypt.obj \
src/modes/cfb/cfb_done.obj src/modes/cfb/cfb_encrypt.obj src/modes/cfb/cfb_getiv.obj \
src/modes/cfb/cfb_setiv.obj src/modes/cfb/cfb_start.obj src/modes/ctr/ctr_decrypt.obj \
src/modes/ctr/ctr_done.obj src/modes/ctr/ctr_encrypt.obj src/modes/ctr/ctr_getiv.obj \
src/modes/ctr/ctr_setiv.obj src/modes/ctr/ctr_start.obj src/modes/ctr/ctr_test.obj \
src/modes/ecb/ecb_decrypt.obj src/modes/ecb/ecb_done.obj src/modes/ecb/ecb_encrypt.obj \
src/modes/ecb/ecb_start.obj src/modes/f8/f8_decrypt.obj src/modes/f8/f8_done.obj src/modes/f8/f8_encrypt.obj \
src/modes/f8/f8_getiv.obj src/modes/f8/f8_setiv.obj src/modes/f8/f8_start.obj src/modes/f8/f8_test_mode.obj \
Expand Down Expand Up @@ -235,7 +236,7 @@ tests/misc_test.obj tests/modes_test.obj tests/mpi_test.obj tests/multi_test.obj
tests/no_null_termination_check_test.obj tests/no_prng.obj tests/padding_test.obj tests/pem_test.obj \
tests/pk_oid_test.obj tests/pkcs_1_eme_test.obj tests/pkcs_1_emsa_test.obj tests/pkcs_1_oaep_test.obj \
tests/pkcs_1_pss_test.obj tests/pkcs_1_test.obj tests/prng_test.obj tests/rotate_test.obj tests/rsa_test.obj \
tests/ssh_test.obj tests/store_test.obj tests/test.obj tests/x25519_test.obj
tests/scrypt_test.obj tests/ssh_test.obj tests/store_test.obj tests/test.obj tests/x25519_test.obj

#The following headers will be installed by "make install"
HEADERS_PUB=src/headers/tomcrypt.h src/headers/tomcrypt_argchk.h src/headers/tomcrypt_cfg.h \
Expand Down
17 changes: 9 additions & 8 deletions makefile.unix
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Expand Up @@ -130,13 +130,14 @@ src/misc/padding/padding_pad.o src/misc/password_free.o src/misc/pbes/pbes.o src
src/misc/pbes/pbes2.o src/misc/pem/pem.o src/misc/pem/pem_pkcs.o src/misc/pem/pem_read.o \
src/misc/pem/pem_ssh.o src/misc/pkcs12/pkcs12_kdf.o src/misc/pkcs12/pkcs12_utf8_to_utf16.o \
src/misc/pkcs5/pkcs_5_1.o src/misc/pkcs5/pkcs_5_2.o src/misc/pkcs5/pkcs_5_test.o \
src/misc/ssh/ssh_decode_sequence_multi.o src/misc/ssh/ssh_encode_sequence_multi.o src/misc/zeromem.o \
src/modes/cbc/cbc_decrypt.o src/modes/cbc/cbc_done.o src/modes/cbc/cbc_encrypt.o \
src/modes/cbc/cbc_getiv.o src/modes/cbc/cbc_setiv.o src/modes/cbc/cbc_start.o \
src/modes/cfb/cfb_decrypt.o src/modes/cfb/cfb_done.o src/modes/cfb/cfb_encrypt.o \
src/modes/cfb/cfb_getiv.o src/modes/cfb/cfb_setiv.o src/modes/cfb/cfb_start.o \
src/modes/ctr/ctr_decrypt.o src/modes/ctr/ctr_done.o src/modes/ctr/ctr_encrypt.o \
src/modes/ctr/ctr_getiv.o src/modes/ctr/ctr_setiv.o src/modes/ctr/ctr_start.o src/modes/ctr/ctr_test.o \
src/misc/scrypt/scrypt.o src/misc/ssh/ssh_decode_sequence_multi.o \
src/misc/ssh/ssh_encode_sequence_multi.o src/misc/zeromem.o src/modes/cbc/cbc_decrypt.o \
src/modes/cbc/cbc_done.o src/modes/cbc/cbc_encrypt.o src/modes/cbc/cbc_getiv.o \
src/modes/cbc/cbc_setiv.o src/modes/cbc/cbc_start.o src/modes/cfb/cfb_decrypt.o \
src/modes/cfb/cfb_done.o src/modes/cfb/cfb_encrypt.o src/modes/cfb/cfb_getiv.o \
src/modes/cfb/cfb_setiv.o src/modes/cfb/cfb_start.o src/modes/ctr/ctr_decrypt.o \
src/modes/ctr/ctr_done.o src/modes/ctr/ctr_encrypt.o src/modes/ctr/ctr_getiv.o \
src/modes/ctr/ctr_setiv.o src/modes/ctr/ctr_start.o src/modes/ctr/ctr_test.o \
src/modes/ecb/ecb_decrypt.o src/modes/ecb/ecb_done.o src/modes/ecb/ecb_encrypt.o \
src/modes/ecb/ecb_start.o src/modes/f8/f8_decrypt.o src/modes/f8/f8_done.o src/modes/f8/f8_encrypt.o \
src/modes/f8/f8_getiv.o src/modes/f8/f8_setiv.o src/modes/f8/f8_start.o src/modes/f8/f8_test_mode.o \
Expand Down Expand Up @@ -256,7 +257,7 @@ tests/misc_test.o tests/modes_test.o tests/mpi_test.o tests/multi_test.o \
tests/no_null_termination_check_test.o tests/no_prng.o tests/padding_test.o tests/pem_test.o \
tests/pk_oid_test.o tests/pkcs_1_eme_test.o tests/pkcs_1_emsa_test.o tests/pkcs_1_oaep_test.o \
tests/pkcs_1_pss_test.o tests/pkcs_1_test.o tests/prng_test.o tests/rotate_test.o tests/rsa_test.o \
tests/ssh_test.o tests/store_test.o tests/test.o tests/x25519_test.o
tests/scrypt_test.o tests/ssh_test.o tests/store_test.o tests/test.o tests/x25519_test.o

#The following headers will be installed by "make install"
HEADERS_PUB=src/headers/tomcrypt.h src/headers/tomcrypt_argchk.h src/headers/tomcrypt_cfg.h \
Expand Down
17 changes: 9 additions & 8 deletions makefile_include.mk
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Expand Up @@ -301,13 +301,14 @@ src/misc/padding/padding_pad.o src/misc/password_free.o src/misc/pbes/pbes.o src
src/misc/pbes/pbes2.o src/misc/pem/pem.o src/misc/pem/pem_pkcs.o src/misc/pem/pem_read.o \
src/misc/pem/pem_ssh.o src/misc/pkcs12/pkcs12_kdf.o src/misc/pkcs12/pkcs12_utf8_to_utf16.o \
src/misc/pkcs5/pkcs_5_1.o src/misc/pkcs5/pkcs_5_2.o src/misc/pkcs5/pkcs_5_test.o \
src/misc/ssh/ssh_decode_sequence_multi.o src/misc/ssh/ssh_encode_sequence_multi.o src/misc/zeromem.o \
src/modes/cbc/cbc_decrypt.o src/modes/cbc/cbc_done.o src/modes/cbc/cbc_encrypt.o \
src/modes/cbc/cbc_getiv.o src/modes/cbc/cbc_setiv.o src/modes/cbc/cbc_start.o \
src/modes/cfb/cfb_decrypt.o src/modes/cfb/cfb_done.o src/modes/cfb/cfb_encrypt.o \
src/modes/cfb/cfb_getiv.o src/modes/cfb/cfb_setiv.o src/modes/cfb/cfb_start.o \
src/modes/ctr/ctr_decrypt.o src/modes/ctr/ctr_done.o src/modes/ctr/ctr_encrypt.o \
src/modes/ctr/ctr_getiv.o src/modes/ctr/ctr_setiv.o src/modes/ctr/ctr_start.o src/modes/ctr/ctr_test.o \
src/misc/scrypt/scrypt.o src/misc/ssh/ssh_decode_sequence_multi.o \
src/misc/ssh/ssh_encode_sequence_multi.o src/misc/zeromem.o src/modes/cbc/cbc_decrypt.o \
src/modes/cbc/cbc_done.o src/modes/cbc/cbc_encrypt.o src/modes/cbc/cbc_getiv.o \
src/modes/cbc/cbc_setiv.o src/modes/cbc/cbc_start.o src/modes/cfb/cfb_decrypt.o \
src/modes/cfb/cfb_done.o src/modes/cfb/cfb_encrypt.o src/modes/cfb/cfb_getiv.o \
src/modes/cfb/cfb_setiv.o src/modes/cfb/cfb_start.o src/modes/ctr/ctr_decrypt.o \
src/modes/ctr/ctr_done.o src/modes/ctr/ctr_encrypt.o src/modes/ctr/ctr_getiv.o \
src/modes/ctr/ctr_setiv.o src/modes/ctr/ctr_start.o src/modes/ctr/ctr_test.o \
src/modes/ecb/ecb_decrypt.o src/modes/ecb/ecb_done.o src/modes/ecb/ecb_encrypt.o \
src/modes/ecb/ecb_start.o src/modes/f8/f8_decrypt.o src/modes/f8/f8_done.o src/modes/f8/f8_encrypt.o \
src/modes/f8/f8_getiv.o src/modes/f8/f8_setiv.o src/modes/f8/f8_start.o src/modes/f8/f8_test_mode.o \
Expand Down Expand Up @@ -432,7 +433,7 @@ tests/misc_test.o tests/modes_test.o tests/mpi_test.o tests/multi_test.o \
tests/no_null_termination_check_test.o tests/no_prng.o tests/padding_test.o tests/pem_test.o \
tests/pk_oid_test.o tests/pkcs_1_eme_test.o tests/pkcs_1_emsa_test.o tests/pkcs_1_oaep_test.o \
tests/pkcs_1_pss_test.o tests/pkcs_1_test.o tests/prng_test.o tests/rotate_test.o tests/rsa_test.o \
tests/ssh_test.o tests/store_test.o tests/test.o tests/x25519_test.o
tests/scrypt_test.o tests/ssh_test.o tests/store_test.o tests/test.o tests/x25519_test.o

# The following headers will be installed by "make install"
HEADERS_PUB=src/headers/tomcrypt.h src/headers/tomcrypt_argchk.h src/headers/tomcrypt_cfg.h \
Expand Down
1 change: 1 addition & 0 deletions sources.cmake
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Expand Up @@ -253,6 +253,7 @@ src/misc/pkcs12/pkcs12_utf8_to_utf16.c
src/misc/pkcs5/pkcs_5_1.c
src/misc/pkcs5/pkcs_5_2.c
src/misc/pkcs5/pkcs_5_test.c
src/misc/scrypt/scrypt.c
src/misc/ssh/ssh_decode_sequence_multi.c
src/misc/ssh/ssh_encode_sequence_multi.c
src/misc/zeromem.c
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6 changes: 6 additions & 0 deletions src/headers/tomcrypt_custom.h
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Expand Up @@ -516,6 +516,8 @@

#define LTC_ARGON2

#define LTC_SCRYPT

/* Keep LTC_NO_HKDF for compatibility reasons
* superseeded by LTC_NO_MISC*/
#ifndef LTC_NO_HKDF
Expand Down Expand Up @@ -687,6 +689,10 @@
#error LTC_ARGON2 requires LTC_BLAKE2B
#endif

#if defined(LTC_SCRYPT) && (!defined(LTC_PKCS_5) || !defined(LTC_SHA256))
#error LTC_SCRYPT requires LTC_PKCS_5 and LTC_SHA256
#endif

#if defined(LTC_CHACHA20POLY1305_MODE) && (!defined(LTC_CHACHA) || !defined(LTC_POLY1305))
#error LTC_CHACHA20POLY1305_MODE requires LTC_CHACHA + LTC_POLY1305
#endif
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8 changes: 8 additions & 0 deletions src/headers/tomcrypt_misc.h
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Expand Up @@ -71,6 +71,14 @@ int argon2_hash(const unsigned char *pwd, unsigned long pwdlen,
unsigned char *out, unsigned long outlen);
#endif /* LTC_ARGON2 */

/* ---- scrypt password-based KDF (RFC 7914) ---- */
#ifdef LTC_SCRYPT
int scrypt_pbkdf(const unsigned char *password, unsigned long password_len,
const unsigned char *salt, unsigned long salt_len,
unsigned long N, unsigned long r, unsigned long p,
unsigned char *out, unsigned long outlen);
#endif /* LTC_SCRYPT */

#ifdef LTC_BCRYPT
int bcrypt_pbkdf_openbsd(const void *secret, unsigned long secret_len,
const unsigned char *salt, unsigned long salt_len,
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3 changes: 3 additions & 0 deletions src/misc/crypt/crypt.c
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Expand Up @@ -458,6 +458,9 @@ const char *crypt_build_settings =
" BCRYPT "
" " NAME_VALUE(LTC_BCRYPT_DEFAULT_ROUNDS) " "
#endif
#if defined(LTC_SCRYPT)
" SCRYPT "
#endif
#if defined(LTC_CRC32)
" CRC32 "
#endif
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