40 lines
883 B
C
40 lines
883 B
C
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/* LibTomCrypt, modular cryptographic library -- Tom St Denis */
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/* SPDX-License-Identifier: Unlicense */
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#include "tomcrypt_private.h"
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/**
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@file pkcs_1_i2osp.c
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Integer to Octet I2OSP, Tom St Denis
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*/
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#ifdef LTC_PKCS_1
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/* always stores the same # of bytes, pads with leading zero bytes
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as required
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*/
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/**
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PKCS #1 Integer to binary
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@param n The integer to store
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@param modulus_len The length of the RSA modulus
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@param out [out] The destination for the integer
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@return CRYPT_OK if successful
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*/
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int pkcs_1_i2osp(void *n, unsigned long modulus_len, unsigned char *out)
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{
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unsigned long size;
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size = mp_unsigned_bin_size(n);
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if (size > modulus_len) {
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return CRYPT_BUFFER_OVERFLOW;
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}
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/* store it */
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zeromem(out, modulus_len);
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return mp_to_unsigned_bin(n, out+(modulus_len-size));
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}
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#endif /* LTC_PKCS_1 */
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