Editing Optimal asymmetric encryption padding (section)

=== Encoding ===
<nowiki>RFC 8017</nowiki><ref>{{cite IETF|title=PKCS #1: RSA Cryptography Specifications Version 2.2|rfc=8017|sectionname=Encryption Operation|section=7.1.1|page=22|last=|first=|author-link=|date=November 2016|publisher=[[Internet Engineering Task Force|IETF]]|access-date=2022-06-04|doi=10.17487/RFC8017}}</ref> for PKCS#1 v2.2 specifies the OAEP scheme as follows for encoding:

# Hash the label ''L'' using the chosen hash function: <math>\mathrm{lHash} = \mathrm{Hash}(L)</math>
# Generate a padding string ''PS'' consisting of <math>k - \mathrm{mLen} - 2 \cdot \mathrm{hLen} - 2</math> bytes with the value 0x00.
# Concatenate ''lHash'', ''PS'', the single byte 0x01, and the message ''M'' to form a data block ''DB'': <math>\mathrm{DB} = \mathrm{lHash} || \mathrm{PS} || \mathrm{0x01} || \mathrm{M}</math>. This data block has length <math>k - \mathrm{hLen} - 1</math> bytes.
# Generate a random seed of length ''hLen''. 
# Use the mask generating function to generate a mask of the appropriate length for the data block: <math>\mathrm{dbMask} = \mathrm{MGF}(\mathrm{seed}, k - \mathrm{hLen} - 1)</math>
# Mask the data block with the generated mask: <math>\mathrm{maskedDB} = \mathrm{DB} \oplus \mathrm{dbMask}</math>
# Use the mask generating function to generate a mask of length ''hLen'' for the seed: <math>\mathrm{seedMask} = \mathrm{MGF}(\mathrm{maskedDB}, \mathrm{hLen})</math>
# Mask the seed with the generated mask: <math>\mathrm{maskedSeed} = \mathrm{seed} \oplus \mathrm{seedMask}</math>
# The encoded (padded) message is the byte 0x00 concatenated with the ''maskedSeed'' and ''maskedDB'': <math>\mathrm{EM} = \mathrm{0x00} || \mathrm{maskedSeed} || \mathrm{maskedDB}</math>