diff --git a/demos/README.txt b/demos/README.txt index 7472821c3b..cdcbd02f94 100644 --- a/demos/README.txt +++ b/demos/README.txt @@ -18,6 +18,9 @@ EVP_MD_demo.c Compute a digest from multiple buffers EVP_MD_stdin.c Compute a digest with data read from stdin EVP_f_md.c Compute a digest using BIO and EVP_f_md +kdf: +hkdf.c Demonstration of HMAC based key derivation + pkey: EVP_PKEY_EC_keygen.c Generate an EC key. diff --git a/demos/kdf/Makefile b/demos/kdf/Makefile new file mode 100644 index 0000000000..b561de43b7 --- /dev/null +++ b/demos/kdf/Makefile @@ -0,0 +1,20 @@ +# +# To run the demos when linked with a shared library (default): +# +# LD_LIBRARY_PATH=../.. ./hkdf + +CFLAGS = -I../../include -g +LDFLAGS = -L../.. +LDLIBS = -lcrypto + +all: hkdf + +%.o: %.c + $(CC) $(CFLAGS) -c $< + +hkdf: hkdf.o + +test: ; + +clean: + $(RM) *.o hkdf diff --git a/demos/kdf/hkdf.c b/demos/kdf/hkdf.c new file mode 100644 index 0000000000..cb7a170e94 --- /dev/null +++ b/demos/kdf/hkdf.c @@ -0,0 +1,104 @@ +/* + * Copyright 2021 The OpenSSL Project Authors. All Rights Reserved. + * + * Licensed under the Apache License 2.0 (the "License"). You may not use + * this file except in compliance with the License. You can obtain a copy + * in the file LICENSE in the source distribution or at + * https://www.openssl.org/source/license.html + */ + +#include +#include +#include +#include +#include +#include + +/* + * test vector from + * https://datatracker.ietf.org/doc/html/rfc5869 + */ + +static unsigned char hkdf_salt[] = { + 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0x0a, 0x0b, + 0x0c +}; + +static unsigned char hkdf_ikm[] = { + 0x0b, 0x0b, 0x0b, 0x0b, 0x0b, 0x0b, 0x0b, 0x0b, 0x0b, 0x0b, 0x0b, 0x0b, + 0x0b, 0x0b, 0x0b, 0x0b, 0x0b, 0x0b, 0x0b, 0x0b, 0x0b, 0x0b +}; + +static unsigned char hkdf_info[] = { + 0xf0, 0xf1, 0xf2, 0xf3, 0xf4, 0xf5, 0xf6, 0xf7, 0xf8, 0xf9 +}; + +/* Expected output keying material */ +static unsigned char hkdf_okm[] = { + 0x3c, 0xb2, 0x5f, 0x25, 0xfa, 0xac, 0xd5, 0x7a, 0x90, 0x43, 0x4f, 0x64, + 0xd0, 0x36, 0x2f, 0x2a, 0x2d, 0x2d, 0x0a, 0x90, 0xcf, 0x1a, 0x5a, 0x4c, + 0x5d, 0xb0, 0x2d, 0x56, 0xec, 0xc4, 0xc5, 0xbf, 0x34, 0x00, 0x72, 0x08, + 0xd5, 0xb8, 0x87, 0x18, 0x58, 0x65 +}; + +int main(int argc, char **argv) +{ + int rv = 1; + EVP_KDF *kdf = NULL; + EVP_KDF_CTX *kctx = NULL; + unsigned char out[42]; + OSSL_PARAM params[5], *p = params; + OSSL_LIB_CTX *library_context = NULL; + + library_context = OSSL_LIB_CTX_new(); + if (library_context == NULL) { + fprintf(stderr, "OSSL_LIB_CTX_new() returned NULL\n"); + goto end; + } + + /* Fetch the key derivation function implementation */ + kdf = EVP_KDF_fetch(library_context, "HKDF", NULL); + if (kdf == NULL) { + fprintf(stderr, "EVP_KDF_fetch() returned NULL\n"); + goto end; + } + + /* Create a context for the key derivation operation */ + kctx = EVP_KDF_CTX_new(kdf); + if (kctx == NULL) { + fprintf(stderr, "EVP_KDF_CTX_new() returned NULL\n"); + goto end; + } + + /* Set the underlying hash function used to derive the key */ + *p++ = OSSL_PARAM_construct_utf8_string(OSSL_KDF_PARAM_DIGEST, + "SHA256", 0); + /* Set input keying material */ + *p++ = OSSL_PARAM_construct_octet_string(OSSL_KDF_PARAM_KEY, hkdf_ikm, + sizeof(hkdf_ikm)); + /* Set application specific information */ + *p++ = OSSL_PARAM_construct_octet_string(OSSL_KDF_PARAM_INFO, hkdf_info, + sizeof(hkdf_info)); + /* Set salt */ + *p++ = OSSL_PARAM_construct_octet_string(OSSL_KDF_PARAM_SALT, hkdf_salt, + sizeof(hkdf_salt)); + *p = OSSL_PARAM_construct_end(); + + /* Derive the key */ + if (EVP_KDF_derive(kctx, out, sizeof(out), params) != 1) { + fprintf(stderr, "EVP_KDF_derive() failed\n"); + goto end; + } + + if (CRYPTO_memcmp(hkdf_okm, out, sizeof(hkdf_okm)) != 0) { + fprintf(stderr, "Generated key does not match expected value\n"); + goto end; + } + + rv = 0; +end: + EVP_KDF_CTX_free(kctx); + EVP_KDF_free(kdf); + OSSL_LIB_CTX_free(library_context); + return rv; +}