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Fix alignment of results of RSA operations when using libgcrypt.

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If the result of an RSA encryption or decryption operation can be represented
in less bytes than given, gcry_mpi_print() will not add leading zero bytes. Fix
this by adding those ourself.
This commit is contained in:
Guus Sliepen 2009-12-19 22:17:39 +01:00
parent 4c68a8cb60
commit f542ef8f9e
1 changed files with 8 additions and 0 deletions
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8
src/gcrypt/rsa.c
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@ -276,6 +276,10 @@ bool rsa_public_encrypt(rsa_t *rsa, void *in, size_t len, void *out) {
gcry_mpi_t outmpi = gcry_mpi_new(len * 8);
gcry_mpi_powm(outmpi, inmpi, rsa->e, rsa->n);
int pad = len - (gcry_mpi_get_nbits(outmpi) + 7) / 8;
while(pad--)
*(char *)out++ = 0;
check(gcry_mpi_print(GCRYMPI_FMT_USG, out,len, NULL, outmpi));
return true;
@ -288,6 +292,10 @@ bool rsa_private_decrypt(rsa_t *rsa, void *in, size_t len, void *out) {
gcry_mpi_t outmpi = gcry_mpi_new(len * 8);
gcry_mpi_powm(outmpi, inmpi, rsa->d, rsa->n);
int pad = len - (gcry_mpi_get_nbits(outmpi) + 7) / 8;
while(pad--)
*(char *)out++ = 0;
check(gcry_mpi_print(GCRYMPI_FMT_USG, out,len, NULL, outmpi));
return true;